I cannot reproduce this crash. Can you please compile KBibTeX with additional debugging information so that source code line numbers are shown in the backtrace as well?

Created attachment 112893 [details]
New crash information added by DrKonqi

kbibtex (e8943a24 (master), near 0.8.50) using Qt 5.9.5

- What I was doing when the application crashed:
it crashes when I try to open one item or if I let it on its own for some time

I recomplied with 'debug' option. I hope it helps

-- Backtrace (Reduced):
#6  0x00007f46261c62f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f45d00dc728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007f45d00d5337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007f462afdcc26 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) (this=0x55b5fe1246d0, _t1=..., _t2=0x55b5fe10b220) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/kbibtexgui_autogen/O3FNYGJQRT/moc_fileview.cpp:277
#11 0x00007f462af65d9d in FileView::currentChanged(QModelIndex const&, QModelIndex const&) (this=0x55b5fe1246d0, current=..., previous=...) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/file/fileview.cpp:186

Created attachment 112894 [details]
New crash information added by DrKonqi

kbibtex (e8943a24 (master), near 0.8.50) using Qt 5.9.5

- What I was doing when the application crashed:
I added enviroment variables and ran kbuildsycoca5 which I had not done before but still crashes.

In the terminal, i get many times:
[warn] epoll_wait: Bad file descriptor

I am sorry for being such a lawsy reporter!

-- Backtrace (Reduced):
#6  0x00007f61712612f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f611c0dc728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007f611c0d5337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007f6176077c26 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) (this=0x557fdcca4b80, _t1=..., _t2=0x557fdcc7f0d0) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/kbibtexgui_autogen/O3FNYGJQRT/moc_fileview.cpp:277
#11 0x00007f6176000d9d in FileView::currentChanged(QModelIndex const&, QModelIndex const&) (this=0x557fdcca4b80, current=..., previous=...) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/file/fileview.cpp:186

Created attachment 112895 [details]
New crash information added by DrKonqi

kbibtex (e8943a24 (master), near 0.8.50) using Qt 5.9.5

- What I was doing when the application crashed:

when installing I get this  around 80%:

[ 81%] Built target kbibtex
[ 81%] Automatic MOC for target kbibtexpart
AutoMoc warning:
  "/home/mfg/sysi/com/down/kbibtex/kbibtex/src/parts/part.cpp"
The file includes the moc file "part.moc", but does not contain a Q_OBJECT, Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY, K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or K_PLUGIN_CLASS_WITH_JSON macro.

[ 82%] Built target kbibtexpart_autogen
[ 86%] Built target kbibtexpart

-- Backtrace (Reduced):
#6  0x00007f884de492f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f87f8058728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007f87f8051337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007f8852c4a472 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
#11 0x00007f8852bd5c8f in FileView::currentChanged(QModelIndex const&, QModelIndex const&) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0

This bug has had its resolution changed, but accidentally has been left in NEEDSINFO status. I am thus closing this bug and setting the status as RESOLVED to reflect the resolution change.

In the lastest master branch, I added some checks on pointer variables in the code regions mentioned in the backtraces you provided earlier.
Please let me know if you can still reproduce this bug.

Thank you Thomas.
I will download and complie again.
Will let you know the result.

Created attachment 115282 [details]
New crash information added by DrKonqi

kbibtex (c3ce32be (master), near 0.8.50) using Qt 5.9.5

I compiled the source with git from today.
The program still crashes as before on opening any entry.

-- Backtrace (Reduced):
#6  0x00007fcb35d482f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fca9d36a728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007fca9d363337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007fcb3aac81c7 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
#11 0x00007fcb3aa5b89b in FileView::currentChanged(QModelIndex const&, QModelIndex const&) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0

Perhaps I am doing something wrong when compliling.
These are the steps I make:

git clone git://anongit.kde.org/kbibtex

export QT_PLUGIN_PATH=/usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
export LD_LIBRARY_PATH=/tmp/usr/lib64
export XDG_DATA_DIRS=/usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbuildsycoca5

cmake -DCMAKE_INSTALL_PREFIX:PATH=/tmp/usr -DCMAKE_BUILD_TYPE=release ../kbibtex
nice -n 4 make -j$(nproc)
make install

/tmp/usr/bin/kbibtex

If you are using non-standard installation paths, you need to adjust some environment variables so that Qt and KDE frameworks know that they have to look there.

For more information, please see https://community.kde.org/Guidelines_and_HOWTOs/Build_from_source#Set_up_the_runtime_environment

Followed your advice, loaded setup-env as suggested but to no avail.
The terminal throws the following:

(kdesrc) mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "c3ce32be (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
Empty filename for XSLT
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 5424
KCrash: Arguments: /tmp/usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/usr/bin/kbibtex
(kdesrc) mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

Something I missed earlier: your KBibTeX instance does not just crash because it starts, but because it opens a file at startup (or tries at least).

Please locate and open in a text editor your kbibtexrc in your home directory or underneath /tmp/usr (open both if both exist). There should be sections starting with

[DocumentList-

The key-value pairs contain among others BibTeX filenames. If possible, send me those .bib files for inspection.

You can remove the section [DocumentList-Open] if you want to remove all of KBibTeX's knowledge on previously opened files. KBibTeX will start without opening any files and should not crash.
Then try to open one of the BibTeX files that were previously in the configuration files and see if KBibTeX then crashes again.

I am trying to perform what you mentioned but now I cannot compile. when I run:
cmake -DCMAKE_INSTALL_PREFIX:PATH=/tmp/usr -DCMAKE_BUILD_TYPE=release ../kbibtex

I get the following error:

CMake Error at CMakeLists.txt:23 (find_package):
  Could not find a package configuration file provided by "ECM" (requested
  version 5.19) with any of the following names:

    ECMConfig.cmake
    ecm-config.cmake

  Add the installation prefix of "ECM" to CMAKE_PREFIX_PATH or set "ECM_DIR"
  to a directory containing one of the above files.  If "ECM" provides a
  separate development package or SDK, be sure it has been installed.

It looks like you are missing the 'extra-cmake-modules' package:
https://packages.ubuntu.com/bionic/extra-cmake-modules

(In reply to manuel fernández from comment #13)
> I am trying to perform what you mentioned but now I cannot compile. when I
> run:
> cmake -DCMAKE_INSTALL_PREFIX:PATH=/tmp/usr -DCMAKE_BUILD_TYPE=release
> ../kbibtex
> 
> I get the following error:
> 
> CMake Error at CMakeLists.txt:23 (find_package):
>   Could not find a package configuration file provided by "ECM" (requested
>   version 5.19) with any of the following names:
> 
>     ECMConfig.cmake
>     ecm-config.cmake
> 
>   Add the installation prefix of "ECM" to CMAKE_PREFIX_PATH or set "ECM_DIR"
>   to a directory containing one of the above files.  If "ECM" provides a
>   separate development package or SDK, be sure it has been installed.

Created attachment 115488 [details]
New crash information added by DrKonqi

kbibtex (3aecb322 (master), near 0.8.50) using Qt 5.9.5

Compiled succesfully but now program crashes without opnening any file. The gui pops up for a few seconds and then crashes.

-- Backtrace (Reduced):
#6  0x00007fa3c4f0e2f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fa377df4728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007fa377ded337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007fa3c9c92717 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
#11 0x00007fa3c9c266bb in FileView::currentChanged(QModelIndex const&, QModelIndex const&) () at /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0

(In reply to Thomas Fischer from comment #12)
> Something I missed earlier: your KBibTeX instance does not just crash
> because it starts, but because it opens a file at startup (or tries at
> least).
> 
> Please locate and open in a text editor your kbibtexrc in your home
> directory or underneath /tmp/usr (open both if both exist). There should be
> sections starting with
> 
> [DocumentList-
> 
> The key-value pairs contain among others BibTeX filenames. If possible, send
> me those .bib files for inspection.
> 
> You can remove the section [DocumentList-Open] if you want to remove all of
> KBibTeX's knowledge on previously opened files. KBibTeX will start without
> opening any files and should not crash.
> Then try to open one of the BibTeX files that were previously in the
> configuration files and see if KBibTeX then crashes again.

Found a kbibtexrc file in /tmp/usr/etc/xdg

[User Interface]
BibTeXStyles=BibTeX|bibtex,biblatex|biblatex
CurrentStyle=bibtex

[Reference Preview Docklet]
PreviewStyles=abbrv (bibtex2html)|abbrv|bibtex2html,acm (bibtex2html)|acm|bibtex2html,alpha (bibtex2html)|alpha|bibtex2html,apalike (bibtex2html)|apalike|bibtex2html,ieeetr (bibtex2html)|ieeetr|bibtex2html,plain (bibtex2html)|plain|bibtex2html,siam (bibtex2html)|siam|bibtex2html,unsrt (bibtex2html)|unsrt|bibtex2html,standard (XML/XSLT)|standard|xml,fancy (XML/XSLT)|fancy|xml,abstract-only (XML/XSLT)|abstractonly|xml

[Search Engines Docklet]
ACMDigitalLibrary=false
Bibsonomy=true
GoogleScholar=true
IEEEXplore=false
PubMed=false
ScienceDirect=false
SpringerLink=false
arXivorg=false

[MainWindow]
ToolBarsMovable=Disabled

Created attachment 115494 [details]
Patch to print extra debug information

This patch adds a number of debug output statements, hopefully at the right places to help me understand what happens on your machine.

When compiling the code, please take care of enabling Debug mode, i.e. passing -DCMAKE_BUILD_TYPE=debug as an argument to cmake.

Please attach both a complete stack trace of the crash as well as all output of KBibTeX on the command line.

Created attachment 115499 [details]
New crash information added by DrKonqi

kbibtex (3aecb322 (master), near 0.8.50) using Qt 5.9.5

compiled with debug option

-- Backtrace (Reduced):
#6  0x00007ff486b0b2f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007ff430c85728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007ff430c7e337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007ff48b942ec4 in FileView::currentElementChanged(QSharedPointer<Element>, File const*) (this=0x55727330e7b0, _t1=..., _t2=0x557273122a10) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/kbibtexgui_autogen/O3FNYGJQRT/moc_fileview.cpp:277
#11 0x00007ff48b8cad2c in FileView::currentChanged(QModelIndex const&, QModelIndex const&) (this=0x55727330e7b0, current=..., previous=...) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/file/fileview.cpp:197

I am sorry, I compiled with debug option but upon rereading your comment, I understand I should do something with the patch / file that you attached. However, I do not know what should I do with it.

(In reply to Thomas Fischer from comment #17)
> Created attachment 115494 [details]
> Patch to print extra debug information
> 
> This patch adds a number of debug output statements, hopefully at the right
> places to help me understand what happens on your machine.
> 
> When compiling the code, please take care of enabling Debug mode, i.e.
> passing -DCMAKE_BUILD_TYPE=debug as an argument to cmake.
> 
> Please attach both a complete stack trace of the crash as well as all output
> of KBibTeX on the command line.

(In reply to manuel fernández from comment #19)
> I am sorry, I compiled with debug option but upon rereading your comment, I
> understand I should do something with the patch / file that you attached.
> However, I do not know what should I do with it.

Attachment 115494 [details] contains a Git patch that describes changes to be applied to the source code.
To apply a patch (a.k.a. diff) with Git, open a terminal and go to the directory where KBibTeX's sources are located. Then run
 git apply PATH-TO-PATCH-FILE
In the best case, you won't get any output, i.e. no warnings or errors to show.
The re-compile the code again.

The attachment will make KBibTeX print a lot more information on what it happening at startup and when opening a file.
Please send me the complete output you get when you launch KBibTeX on the command line.

To revert the patch later and to restore the "official" code, run
 git checkout -- src

Created attachment 115512 [details]
New crash information added by DrKonqi

kbibtex (3aecb322 (master), near 0.8.50) using Qt 5.9.5

Applied your patch bug394659-extra-debug.diff and compiled.
Hope these results help.

-- Backtrace (Reduced):
#6  0x00007fad98ae42f0 in QUrl::isLocalFile() const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fad0536a728 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
#8  0x00007fad05363337 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
[...]
#10 0x00007fad9d91702a in FileView::currentElementChanged(QSharedPointer<Element>, File const*) (this=0x5612cbbd8620, _t1=..., _t2=0x5612cbbbb730) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/kbibtexgui_autogen/O3FNYGJQRT/moc_fileview.cpp:277
#11 0x00007fad9d89ee91 in FileView::currentChanged(QModelIndex const&, QModelIndex const&) (this=0x5612cbbd8620, current=..., previous=...) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/gui/file/fileview.cpp:199

Created attachment 115518 [details]
kbibtexrc file

for comment 12

(In reply to Thomas Fischer from comment #12)
> Something I missed earlier: your KBibTeX instance does not just crash
> because it starts, but because it opens a file at startup (or tries at
> least).
> 
> Please locate and open in a text editor your kbibtexrc in your home
> directory or underneath /tmp/usr (open both if both exist). There should be
> sections starting with
> 
> [DocumentList-
> 
> The key-value pairs contain among others BibTeX filenames. If possible, send
> me those .bib files for inspection.
> 
> You can remove the section [DocumentList-Open] if you want to remove all of
> KBibTeX's knowledge on previously opened files. KBibTeX will start without
> opening any files and should not crash.
> Then try to open one of the BibTeX files that were previously in the
> configuration files and see if KBibTeX then crashes again.

Found two kbibtexrc files. (in .config and .kde/share/config directories) Apparently the one in use is in .config directory
Even if I open a very simple .bib file with one record (downloaded from the internet) the programme crashes.

Thank you for the information so far. But I still need KBibTeX's debug output when launched in a terminal, e.g. Konsole.

(In reply to Thomas Fischer from comment #24)
> Thank you for the information so far. But I still need KBibTeX's debug
> output when launched in a terminal, e.g. Konsole.

Here it is. Sorry for being so inefficient!

mfg@luz:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "3aecb322 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
kbibtex.gui: m_current is null?  NULL
kbibtex.gui: model is null?  not null
Empty filename for XSLT
Empty filename for XSLT
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.program: About to show main window
WebEngineContext used before QtWebEngine::initialize() or OpenGL context creation failed.
kbibtex.program: From config file  "file:///home/mfg/acad/dif/curri/ref-mias/mfg-arti.bib"  (statusFlag= 2 )
kbibtex.program: Opening URL previously not open:  "file:///home/mfg/acad/dif/curri/ref-mias/mfg-arti.bib"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: URL now open:  "/home/mfg/acad/dif/curri/ref-mias/mfg-arti.bib"
kbibtex.program: From config file  "file:///home/mfg/acad/ext/ref/phys.bib"  (statusFlag= 2 )
kbibtex.program: Opening URL previously not open:  "file:///home/mfg/acad/ext/ref/phys.bib"
kbibtex.program: URL now open:  "/home/mfg/acad/ext/ref/phys.bib"
kbibtex.program: From config file  "file:///home/mfg/Desktop/perna10.2307_1971423.txt"  (statusFlag= 2 )
kbibtex.program: Opening URL previously not open:  "file:///home/mfg/Desktop/perna10.2307_1971423.txt"
kbibtex.program: URL now open:  "/home/mfg/Desktop/perna10.2307_1971423.txt"
kbibtex.program: From config file  "file:///home/mfg/acad/dif/curri/ref-mias/mfg-arti.bib"  (statusFlag= 4 )
kbibtex.program: From config file  "file:///home/mfg/acad/ext/ref/phys.bib"  (statusFlag= 4 )
kbibtex.program: From config file  "file:///home/mfg/acad/dif/curri/ref-mias/mfg-arti.bib"  (statusFlag= 1 )
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kbibtex.program: PATH= /home/mfg/.config/composer/vendor/bin:/home/mfg/.nvm/versions/node/v4.2.3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
kbibtex.program: LD_LIBRARY_PATH= 
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/var/lib/snapd/desktop
kbibtex.program: QT_PLUGIN_PATH= 
kbibtex.program: KDEDIRS= 
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.gui: m_current is null?  NULL
kbibtex.gui: model is null?  not null
kbibtex.io: No or only an incomplete installation of BibUtils found
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kbibtex.gui: m_current is null?  NULL
kbibtex.gui: model is null?  not null
kbibtex.program: From config file  "file:///home/mfg/acad/ext/ref/phys.bib"  (statusFlag= 1 )
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
kbibtex.program: Invoking 'return programCore.exec()'
kbibtex.gui: m_current is null?  not null
kbibtex.gui: model is null?  not null
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 25551
KCrash: Arguments: /tmp/usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/usr/bin/kbibtex
mfg@luz:~/sysi/com/down/kbibtex/kbibtex$

Created attachment 115552 [details]
Second patch to print more debug output

Comment 25 contained the output I was looking for. Unfortunately, it did not help me to trace back the problem. So, here comes a new patch which prints debug output at other places.
Please test it. It should be possible to apply this patch even with the first one still applied. If you encounter problems applying this patch, run
  git checkout -- src
first.

Also, I saw that KBibTeX tried to open a .txt file. I wonder what this file's content may be. Could you please tell me more? In case the file is not too large, just attach it to the bug report; otherwise post the first 10 lines or so.

(In reply to Thomas Fischer from comment #26)
> Created attachment 115552 [details]
> Second patch to print more debug output
> 
> Comment 25 contained the output I was looking for. Unfortunately, it did not
> help me to trace back the problem. So, here comes a new patch which prints
> debug output at other places.
> Please test it. It should be possible to apply this patch even with the
> first one still applied. If you encounter problems applying this patch, run
>   git checkout -- src
> first.
> 
> Also, I saw that KBibTeX tried to open a .txt file. I wonder what this
> file's content may be. Could you please tell me more? In case the file is
> not too large, just attach it to the bug report; otherwise post the first 10
> lines or so.

Here is the console output once the patch was applied:

mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "4c322b11 (master)"                                                                                                                                
QCommandLineParser: option not defined: "author"                                                                                                                                             
QCommandLineParser: option not defined: "license"                                                                                                                                            
QCommandLineParser: option not defined: "desktopfile"                                                                                                                                        
Empty filename for XSLT                                                                                                                                                                      
Empty filename for XSLT                                                                                                                                                                      
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 6861
KCrash: Arguments: /tmp/usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/usr/bin/kbibtex
mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

sorry, compiled with release, let me do it again!

(In reply to manuel fernández from comment #27)
> (In reply to Thomas Fischer from comment #26)
> > Created attachment 115552 [details]
> > Second patch to print more debug output
> > 
> > Comment 25 contained the output I was looking for. Unfortunately, it did not
> > help me to trace back the problem. So, here comes a new patch which prints
> > debug output at other places.
> > Please test it. It should be possible to apply this patch even with the
> > first one still applied. If you encounter problems applying this patch, run
> >   git checkout -- src
> > first.
> > 
> > Also, I saw that KBibTeX tried to open a .txt file. I wonder what this
> > file's content may be. Could you please tell me more? In case the file is
> > not too large, just attach it to the bug report; otherwise post the first 10
> > lines or so.
> 
> Here is the console output once the patch was applied:
> 
> mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
> kbibtex.program: Starting KBibTeX version "4c322b11 (master)"               
> 
> QCommandLineParser: option not defined: "author"                            
> 
> QCommandLineParser: option not defined: "license"                           
> 
> QCommandLineParser: option not defined: "desktopfile"                       
> 
> Empty filename for XSLT                                                     
> 
> Empty filename for XSLT                                                     
> 
> kbibtex.program: WebEngine is available, using it instead of WebKit or HTML
> KPart (both neither considered nor tested for) for HTML/Web preview.
> No file found for ".xml" , even though update-mime-info said it would exist.
> Either it was just removed, or the directory doesn't have executable
> permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
> kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts
> component to view and edit bibliographic files" ) for mime type
> "text/x-bibtex" through library "kbibtexpart"
> kf5.kxmlgui: this does not work on a KActionCollection containing actions!
> kbibtex.io: BibUtils found, using it to import/export certain types of
> bibliographies
> kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
> "fe" ) , treating as comment
> kf5.kio.core: KSambaShare: Could not find smb.conf!
> kbibtex.program: Located KPart service: "kbibtexpart" with description
> "KParts component to view and edit bibliographic files" from library
> "kbibtexpart"
> No file found for ".xml" , even though update-mime-info said it would exist.
> Either it was just removed, or the directory doesn't have executable
> permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
> No file found for ".xml" , even though update-mime-info said it would exist.
> Either it was just removed, or the directory doesn't have executable
> permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
> No file found for ".xml" , even though update-mime-info said it would exist.
> Either it was just removed, or the directory doesn't have executable
> permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
> kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts
> component to view and edit bibliographic files" ) for mime type
> "text/x-bibtex" through library "kbibtexpart"
> kf5.kxmlgui: this does not work on a KActionCollection containing actions!
> KCrash: crashing... crashRecursionCounter = 2
> KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 6861
> KCrash: Arguments: /tmp/usr/bin/kbibtex 
> KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from
> kdeinit
> sock_file=/run/user/1000/kdeinit5__0
> 
> [1]+  Stopped                 /tmp/usr/bin/kbibtex
> mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

------------------
here is the output with patch2

mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "4c322b11 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
Empty filename for XSLT
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 8750
KCrash: Arguments: /tmp/usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/usr/bin/kbibtex
mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

Created attachment 115553 [details]
text file you asked for. It is a bib file but has extension .txt

I noticed another odd thing: The crash reports tell me that you mix KBibTeX libraries from two different prefixes. This is most likely wrong and may cause trouble.

/usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
/tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0

Please uninstall KBibTeX from your distributions package management system and remove any residual KBibTeX files in /usr, i.. anything that contains 'kbibtex' in its filename.

Then, ensure that you have applied both patches (attachment 115494 [details] and attachment 115552 [details]) and compiled the code with CMAKE_BUILD_TYPE=debug
Again, please send command line output and the complete DrKonqi stack trace output.

(In reply to Thomas Fischer from comment #31)
> I noticed another odd thing: The crash reports tell me that you mix KBibTeX
> libraries from two different prefixes. This is most likely wrong and may
> cause trouble.
> 
> /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so
> /tmp/usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
> 
> Please uninstall KBibTeX from your distributions package management system
> and remove any residual KBibTeX files in /usr, i.. anything that contains
> 'kbibtex' in its filename.
> 
> Then, ensure that you have applied both patches (attachment 115494 [details]
> and attachment 115552 [details]) and compiled the code with
> CMAKE_BUILD_TYPE=debug
> Again, please send command line output and the complete DrKonqi stack trace
> output.

Purged kbibtex and kbibtex-data with muon
renamed kbibtexrc to kbibtexrc.old in .config and /.kde/share/apps/

downloaded kbibtex, applied both patches
compiled and when executed got a message saying kparts was missing and would have only limited functionality

this is the console output

(kdesrc) mfg@luz:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "14b263d2 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
kbibtex.gui: m_current is null?  NULL
kbibtex.gui: model is null?  not null
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.systemmonitor.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.systemmonitor.desktop"
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.drkonqi.desktop"
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.gui: List of entry layouts is empty
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kbibtex.program: About to show main window
kbibtex.program: PATH= /home/mfg/kde/usr/bin:/usr/bin:/home/mfg/.config/composer/vendor/bin:/home/mfg/.nvm/versions/node/v4.2.3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
kbibtex.program: LD_LIBRARY_PATH= 
kbibtex.program: XDG_DATA_DIRS= /home/mfg/kde/usr/share:/usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/var/lib/snapd/desktop:/usr/share
kbibtex.program: QT_PLUGIN_PATH= /home/mfg/kde/usr/lib/plugins:/home/mfg/kde/usr/lib64/plugins:/home/mfg/kde/usr/lib/x86_64-linux-gnu/plugins:/usr/plugins:
kbibtex.program: KDEDIRS= 
kbibtex.program: QCoreApplication::libraryPaths= "/usr/lib/x86_64-linux-gnu/qt5/plugins:/tmp/usr/bin"
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Invoking 'return programCore.exec()'
kbibtex.io: No or only an incomplete installation of BibUtils found
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Opening URL previously not open:  "file:///home/mfg/Desktop/nonlin-schro.bib"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: URL now open:  "/home/mfg/Desktop/nonlin-schro.bib"
kbibtex.program: Using service "Embedded Advanced Text Editor" ( "" ) for mime type "text/x-bibtex" through library "kf5/parts/katepart"
kbibtex.program: PATH= /home/mfg/kde/usr/bin:/usr/bin:/home/mfg/.config/composer/vendor/bin:/home/mfg/.nvm/versions/node/v4.2.3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
kbibtex.program: LD_LIBRARY_PATH= 
kbibtex.program: XDG_DATA_DIRS= /home/mfg/kde/usr/share:/usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/var/lib/snapd/desktop:/usr/share
kbibtex.program: QT_PLUGIN_PATH= /home/mfg/kde/usr/lib/plugins:/home/mfg/kde/usr/lib64/plugins:/home/mfg/kde/usr/lib/x86_64-linux-gnu/plugins:/usr/plugins:
kbibtex.program: KDEDIRS= 
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/usr/bin pid = 19365
KCrash: Arguments: /tmp/usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/usr/bin/kbibtex
(kdesrc) mfg@luz:~/sysi/com/down/kbibtex/kbibtex$

Created attachment 115577 [details]
New crash information added by DrKonqi

kbibtex (14b263d2 (master), near 0.8.50) using Qt 5.9.5

when file is opened the program crashes.

-- Backtrace (Reduced):
#6  0x00007fedea887a90 in KService::library() const () at /usr/lib/x86_64-linux-gnu/libKF5Service.so.5
#7  0x000055afbfd6e60d in OpenFileInfo::listOfServices() (this=0x55afc2690340) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/program/openfileinfo.cpp:332
#8  0x000055afbfd39eba in DocumentListView::currentChanged(QModelIndex const&, QModelIndex const&) (this=0x55afc14c1e10, current=...) at /home/mfg/sysi/com/down/kbibtex/kbibtex/src/program/documentlist.cpp:369
#9  0x00007fede9284951 in  () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
[...]
#11 0x00007fede826667a in QItemSelectionModel::currentChanged(QModelIndex const&, QModelIndex const&) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5

(In reply to manuel fernández from comment #33)
> Created attachment 115577 [details]
> New crash information added by DrKonqi
> 
> kbibtex (14b263d2 (master), near 0.8.50) using Qt 5.9.5
> 
> when file is opened the program crashes.
> 
> -- Backtrace (Reduced):
> #6  0x00007fedea887a90 in KService::library() const () at
> /usr/lib/x86_64-linux-gnu/libKF5Service.so.5
> #7  0x000055afbfd6e60d in OpenFileInfo::listOfServices()
> (this=0x55afc2690340) at
> /home/mfg/sysi/com/down/kbibtex/kbibtex/src/program/openfileinfo.cpp:332
> #8  0x000055afbfd39eba in DocumentListView::currentChanged(QModelIndex
> const&, QModelIndex const&) (this=0x55afc14c1e10, current=...) at
> /home/mfg/sysi/com/down/kbibtex/kbibtex/src/program/documentlist.cpp:369
> #9  0x00007fede9284951 in  () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
> [...]
> #11 0x00007fede826667a in QItemSelectionModel::currentChanged(QModelIndex
> const&, QModelIndex const&) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
This crash should be addressed in commit 220c9dcc21c4991342.
It is caused that the KBibTeX program did not correctly handle cases where it could not find its own libraries.

Git commit 220c9dcc21c499134200bd2ff461edcb47483356 by Thomas Fischer.
Committed on 26/10/2018 at 21:00.
Pushed by thomasfischer into branch 'master'.

Adding robustness and verbosity when locating KParts

- Adding both comments and debug output in code sections on locating KParts
  used to edit bibliography files.
- Addressing bug where code depended on a valid return value of QList::last()
  not considering that the list may be empty.

M  +32   -12   src/program/openfileinfo.cpp

https://commits.kde.org/kbibtex/220c9dcc21c499134200bd2ff461edcb47483356

> downloaded kbibtex, applied both patches
> compiled and when executed got a message saying kparts was missing and would
> have only limited functionality
This message, various other debug/warn messages, and the final crash suggest that the KBibTeX installation you launched was incomplete, i.e. the KBibTeX program could not locate its own libraries.
Please see the instructions at https://userbase.kde.org/KBibTeX/Development in sections "Compiling the Code" and "Installation" for further details.

Program no longer crashes ....
However, I now only see the bibtex entries like I do in kate, but inside kbibtex.

Here is what the terminal gives:

mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "220c9dcc (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
Empty filename for XSLT
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.gui: List of entry layouts is empty
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "Embedded Advanced Text Editor" ( "" ) for mime type "text/x-bibtex" through library "kf5/parts/katepart"
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= 
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop
kbibtex.program: QT_PLUGIN_PATH= 
kbibtex.program: KDEDIRS= 
kbibtex.program: QCoreApplication::libraryPaths= "/usr/lib/x86_64-linux-gnu/qt5/plugins:/tmp/usr/bin"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Using service "Embedded Advanced Text Editor" ( "" ) for mime type "text/x-bibtex" through library "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
No Zotero credentials stored in KWallet
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Could not locate KBibTeX's KPart neither by MIME type search, nor by desktop name
kbibtex.gui: There should be no use for a default case here!
kf5.kxmlgui: 0x55bcb2b02758 deleted without having been removed from the factory first. This will leak standalone popupmenus and could lead to crashes.
mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

I do not know if the problem has to do with a warning when I compile:

AutoMoc warning:
  "/home/mfg/sysi/com/down/kbibtex/kbibtex/src/parts/part.cpp"
The file includes the moc file "part.moc", but does not contain a Q_OBJECT, Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY, K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or K_PLUGIN_CLASS_WITH_JSON macro.

added paths:
export QT_PLUGIN_PATH=/usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
export LD_LIBRARY_PATH=/tmp/usr/lib64
export XDG_DATA_DIRS=/usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share

compiled again, but still program says no kparts for .bib files.
Here is the terminal output

mfg@bix:~/sysi/com/down/kbibtex/kbibtex$ /tmp/usr/bin/kbibtex     
kbibtex.program: Starting KBibTeX version "220c9dcc (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.systemmonitor.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.systemmonitor.desktop"
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.drkonqi.desktop"
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/usr/lib64
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/usr/lib64
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/usr/lib64
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/usr/lib64
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/usr/lib64
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/tmp/usr/share
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
Aborting aboutToFinish handling.
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
mfg@bix:~/sysi/com/down/kbibtex/kbibtex$

Looked for automoc package but there is only automoc for qt4 and not qt5 (muon, kubuntu 18.04)

Created attachment 115924 [details]
Script that pulls KBibTeX's sources from Git, compiles them, and install them in temporary directory

This attachment is a Bash script that pulls KBibTeX's sources from a Git repository, compiles them, and installs them -- all in temporary directories without interfering with 'real' installations.
The script takes one mandatory parameter (the Git repository's anonymous URL) and one optional parameter (branch or tag, default is 'master').

Usage example:
./run-kbibtex.sh https://cgit.kde.org/kbibtex.git master

Attachment 115924 [details] will allow you to try out the lastest KBibTeX source code, although without any of the patches proposed already in this bug report.
To successfully compile the code, you may have to install various additional programs or libraries through your Linux distribution's package management system.

Am I doing something wrong or is there a typo error in the repository address ...
Thank you for all your help!

mfg@bix:~/sysi/com/down/kbibtex$ ./run-kbibtex.sh https://cgit.kde.org/kbibtex.git master
Application:                  kbibtex
Expected application binary:  /tmp/mfg-kbibtex-usr/bin/kbibtex
Git URL:                      https://cgit.kde.org/kbibtex.git
Git branch or tag:            master
Installation prefix:          /tmp/mfg-kbibtex-usr
Build directory:              /tmp/mfg-kbibtex-build-b938ad44c35d07bcc8bf49776fe2581f
Cloning into 'mfg-kbibtex-git-a43a6941f630254995760b2d5e4213d9'...
fatal: repository 'https://cgit.kde.org/kbibtex.git/' not found
mfg@bix:~/sysi/com/down/kbibtex$

Sorry, copy&paste error. It should be
https://anongit.kde.org/kbibtex.git
as the repository's URL.

(In reply to manuel fernández from comment #43)
> Am I doing something wrong or is there a typo error in the repository
> address ...
> Thank you for all your help!
> 
> mfg@bix:~/sysi/com/down/kbibtex$ ./run-kbibtex.sh
> https://cgit.kde.org/kbibtex.git master
> Application:                  kbibtex
> Expected application binary:  /tmp/mfg-kbibtex-usr/bin/kbibtex
> Git URL:                      https://cgit.kde.org/kbibtex.git
> Git branch or tag:            master
> Installation prefix:          /tmp/mfg-kbibtex-usr
> Build directory:             
> /tmp/mfg-kbibtex-build-b938ad44c35d07bcc8bf49776fe2581f
> Cloning into 'mfg-kbibtex-git-a43a6941f630254995760b2d5e4213d9'...
> fatal: repository 'https://cgit.kde.org/kbibtex.git/' not found
> mfg@bix:~/sysi/com/down/kbibtex$

Program compiles and runs thereafter.
When I try to open a .bib file a warning pops up saying:

No part available for file 'phys.bib'.

The tail of what came out on the terminal is:

 Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/zotero.png
-- Installing: /tmp/mfg-kbibtex-usr/share/man/man1/kbibtex.1
kbuildsycoca5 running...
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.systemmonitor.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.systemmonitor.desktop"
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.drkonqi.desktop"
kbibtex.program: Starting KBibTeX version "98402b78 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/mfg-kbibtex-usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/mfg-kbibtex-usr/lib
kbibtex.program: XDG_DATA_DIRS= /usr/share:/usr/local/share:/tmp/mfg-kbibtex-usr/share
kbibtex.program: QT_PLUGIN_PATH= :/tmp/mfg-kbibtex-usr/lib/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/mfg-kbibtex-usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/mfg-kbibtex-usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= /tmp/mfg-kbibtex-usr/lib
kbibtex.program: XDG_DATA_DIRS= /usr/share:/usr/local/share:/tmp/mfg-kbibtex-usr/share
kbibtex.program: QT_PLUGIN_PATH= :/tmp/mfg-kbibtex-usr/lib/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: Could not instantiate read-write part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
org.kde.kcoreaddons: Error loading plugin "kbibtexpart" "The shared library was not found." 
Plugin search paths are ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/tmp/mfg-kbibtex-usr/bin") 
The environment variable QT_PLUGIN_PATH might be not correctly set
kbibtex.program: Could not instantiate part for service "BibTeX Viewer and Editor" (mimeType= "text/x-bibtex" , library= "kbibtexpart" , error msg= "The shared library was not found." )
kbibtex.gui: There should be no use for a default case here!
mfg@bix:~/sysi/com/down/kbibtex$

searched the plugin where kbibtexpart.so is located. It is:

/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins

but in the last lines of the terminal output:

kbibtex.program: QT_PLUGIN_PATH= :/tmp/mfg-kbibtex-usr/lib/plugins/

so as the output suggests maybe:
The environment variable QT_PLUGIN_PATH might be not correctly set

--------------------------------------
try to add the path:

mfg@bix:~/sysi/com/down/kbibtex$ export QT_PLUGIN_PATH=/usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/:/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/

terminal output was then:

mfg@bix:~/sysi/com/down/kbibtex$ /tmp/mfg-kbibtex-usr/bin/kbibtex            
kbibtex.program: Starting KBibTeX version "98402b78 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
kbibtex.networking: Failed to initialize XSL transformation based on file 'arxiv2bibtex.xsl'
kbibtex.networking: Generated XSLT filename was ' "kbibtex/arxiv2bibtex.xsl" '
Empty filename for XSLT
kbibtex.networking: Failed to initialize XSL transformation based on file 'ieeexploreapiv1-to-bibtex.xsl'
kbibtex.networking: Generated XSLT filename was ' "kbibtex/ieeexploreapiv1-to-bibtex.xsl" '
Empty filename for XSLT
kbibtex.networking: Failed to initialize XSL transformation based on file 'pubmed2bibtex.xsl'
kbibtex.networking: Generated XSLT filename was ' "kbibtex/pubmed2bibtex.xsl" '
Empty filename for XSLT
kbibtex.networking: Failed to initialize XSL transformation based on file 'pam2bibtex.xsl'
kbibtex.networking: Generated XSLT filename was ' "kbibtex/pam2bibtex.xsl" '
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.gui: List of entry layouts is empty
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kbibtex.program: PATH= /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-9-oracle/bin:/usr/lib/jvm/java-9-oracle/db/bin
kbibtex.program: LD_LIBRARY_PATH= 
kbibtex.program: XDG_DATA_DIRS= /usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop
kbibtex.program: QT_PLUGIN_PATH= /usr/lib/plugins:/usr/lib/qt5/plugins:/tmp/usr/lib64/plugins/:/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/
kbibtex.program: KDEDIRS= 
kbibtex.program: QCoreApplication::libraryPaths= "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins:/usr/lib/x86_64-linux-gnu/qt5/plugins:/tmp/mfg-kbibtex-usr/bin"
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Using service "Embedded Advanced Text Editor" ( "" ) for mime type "text/x-bibtex" through library "kf5/parts/katepart"
kf5.kxmlgui: cannot find .rc file "kbibtexui.rc" for component "kbibtex"
kf5.kxmlgui: 0x7fc834018a98 deleted without having been removed from the factory first. This will leak standalone popupmenus and could lead to crashes.
mfg@bix:~/sysi/com/down/kbibtex$ 

------------------------
but then it shows .bib file like in kate text file instead of the nice kbibtex ...

this is as far as I could get ...

Created attachment 115934 [details]
Script that pulls KBibTeX's sources from Git, compiles them, and install them in temporary directory

Revised version of 'run-kbibtex.sh'. Primary change is how QT_PLUGIN_PATH is assembled.

Alas! it works. Brilliant! Many many thanks.

I do not know whether this is the right place to ask: 

If I change the four lines of the script run-kbibtex.sh near the beginning instead of /tmp with /usr/local/bin 
in order to use the program without having to compile when I turn the machine off and on. Will it work? Is this a reasonable place to locate it?

GIT_DIRECTORY="/tmp/${USER}-${APPLICATION}-git-$(md5sum <<<"${GIT_URL}" | cut -f 1 -d ' ')"
INSTALL_PREFIX="/tmp/${USER}-${APPLICATION}-usr"
BUILD_DIRECTORY="/tmp/${USER}-${APPLICATION}-build-$(md5sum <<<"${GIT_URL}${GIT_BRANCH}" | cut -f 1 -d ' ')"
XDG_DIRECTORY="/tmp/${USER}-${APPLICATION}-xdg-$(md5sum <<<"${GIT_URL}${GIT_BRANCH}" | cut -f 1 -d ' ')"


--------------------------------
This is the output of new installation:
mfg@bix:~/sysi/com/down/kbibtex$ ./run-kbibtex.sh https://anongit.kde.org/kbibtex.git master
Application:                  kbibtex
Expected application binary:  /tmp/mfg-kbibtex-usr/bin/kbibtex
Git URL:                      https://anongit.kde.org/kbibtex.git
Git branch or tag:            master
Installation prefix:          /tmp/mfg-kbibtex-usr
Build directory:              /tmp/mfg-kbibtex-build-3274add80257946b78e6f19d1c4ff9b9
Already on 'master'
Your branch is up to date with 'origin/master'.
Already up to date.
-- Unity build disabled (default), use option UNITY_BUILD to enable it
-- Poppler: Qt5 requires Core
-- Found ICU 60.2.0
-- Found Qca-qt5 2.1.3 and QtOAuth
-- Found both QtWebEngine and QtWebKit, preferring to use QtWebEngine
-- The following OPTIONAL packages have been found:

 * Qt5Qml (required version >= 5.9.5)
 * Qt5Quick (required version >= 5.9.5)
 * Qt5WebChannel (required version >= 5.9.5)
 * Qt5Positioning (required version >= 5.9.5)
 * Qt5WebEngineCore (required version >= 5.9.5)
 * Qt5PrintSupport (required version >= 5.9.5)
 * Qt5WebEngineWidgets (required version >= 5.6.0)
 * Qt5WebKitWidgets (required version >= 5.6.0)
 * KF5DocTools
 * PkgConfig
 * Qca-qt5 (required version >= 2.1.0)
 * QtOAuth
 * SharedMimeInfo, A database of common MIME types, <http://freedesktop.org/wiki/Software/shared-mime-info/>

-- The following REQUIRED packages have been found:

 * ECM (required version >= 5.19)
 * Qt5Core
 * Qt5Gui (required version >= 5.9.5)
 * Qt5Widgets
 * Qt5Network
 * Qt5XmlPatterns
 * Qt5Concurrent
 * Qt5 (required version >= 5.6.0)
 * Qt5Test (required version >= 5.6.0)
 * Gettext
 * PythonInterp
 * KF5I18n (required version >= 5.26.0)
 * KF5XmlGui (required version >= 5.26.0)
 * KF5KIO (required version >= 5.26.0)
 * KF5IconThemes (required version >= 5.26.0)
 * KF5ItemViews (required version >= 5.26.0)
 * KF5Completion (required version >= 5.26.0)
 * KF5Parts (required version >= 5.26.0)
 * KF5CoreAddons (required version >= 5.26.0)
 * KF5Service (required version >= 5.26.0)
 * KF5Wallet (required version >= 5.26.0)
 * KF5Crash (required version >= 5.26.0)
 * KF5 (required version >= 5.26.0)
 * Poppler, A PDF rendering library, <http://poppler.freedesktop.org>
 * ICU

-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/mfg-kbibtex-build-3274add80257946b78e6f19d1c4ff9b9
[  0%] Built target doc-index-cache-bz2
[  1%] Automatic MOC for target kbibtexconfig
[  1%] Built target doc-kbibtex-1
[  1%] Built target kbibtexconfig_autogen
[  4%] Built target kbibtexconfig
[  5%] Automatic MOC for target kbibtexdata
[  5%] Built target kbibtexdata_autogen
[ 11%] Built target kbibtexdata
[ 12%] Automatic MOC for target kbibtexdatatest
[ 12%] Automatic MOC for target kbibtexio
[ 12%] Built target kbibtexdatatest_autogen
[ 12%] Built target kbibtexio_autogen
[ 14%] Built target kbibtexdatatest
[ 28%] Built target kbibtexio
[ 28%] Automatic MOC for target kbibtexproc
[ 29%] Automatic MOC for target kbibtexfilestest
[ 30%] Automatic MOC for target kbibtexnetworking
[ 30%] Automatic MOC for target kbibtexiotest
[ 30%] Built target kbibtexproc_autogen
[ 30%] Built target kbibtexiotest_autogen
[ 30%] Built target kbibtexfilestest_autogen
[ 30%] Built target kbibtexnetworking_autogen
[ 35%] Built target kbibtexproc
[ 37%] Built target kbibtexfilestest
[ 39%] Built target kbibtexiotest
[ 57%] Built target kbibtexnetworking
[ 57%] Automatic MOC for target kbibtexnetworkingtest
[ 57%] Automatic MOC for target kbibtexgui
[ 57%] Built target kbibtexnetworkingtest_autogen
[ 57%] Built target kbibtexgui_autogen
[ 59%] Built target kbibtexnetworkingtest
[ 80%] Built target kbibtexgui
[ 81%] Automatic MOC for target kbibtextest
[ 82%] Automatic MOC for target kbibtexpart
[ 82%] Automatic MOC for target kbibtex
AutoMoc warning:
  "/tmp/mfg-kbibtex-git-2390e60c06eb02156ed552f6b0b71b24/src/parts/part.cpp"
The file includes the moc file "part.moc", but does not contain a Q_OBJECT, Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY, K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or K_PLUGIN_CLASS_WITH_JSON macro.

[ 82%] Built target kbibtexpart_autogen
[ 82%] Built target kbibtextest_autogen
[ 82%] Built target kbibtex_autogen
[ 86%] Built target kbibtexpart
[ 89%] Built target kbibtextest
[100%] Built target kbibtex
[  1%] Automatic MOC for target kbibtexconfig
[  1%] Built target doc-kbibtex-1
[  1%] Built target doc-index-cache-bz2
[  1%] Built target kbibtexconfig_autogen
[  4%] Built target kbibtexconfig
[  5%] Automatic MOC for target kbibtexdata
[  5%] Built target kbibtexdata_autogen
[ 11%] Built target kbibtexdata
[ 12%] Automatic MOC for target kbibtexio
[ 12%] Automatic MOC for target kbibtexdatatest
[ 12%] Built target kbibtexdatatest_autogen
[ 12%] Built target kbibtexio_autogen
[ 14%] Built target kbibtexdatatest
[ 28%] Built target kbibtexio
[ 29%] Automatic MOC for target kbibtexnetworking
[ 29%] Automatic MOC for target kbibtexproc
[ 29%] Automatic MOC for target kbibtexiotest
[ 30%] Automatic MOC for target kbibtexfilestest
[ 30%] Built target kbibtexproc_autogen
[ 30%] Built target kbibtexiotest_autogen
[ 30%] Built target kbibtexnetworking_autogen
[ 30%] Built target kbibtexfilestest_autogen
[ 32%] Built target kbibtexiotest
[ 37%] Built target kbibtexproc
[ 39%] Built target kbibtexfilestest
[ 57%] Built target kbibtexnetworking
[ 57%] Automatic MOC for target kbibtexnetworkingtest
[ 57%] Automatic MOC for target kbibtexgui
[ 57%] Built target kbibtexnetworkingtest_autogen
[ 57%] Built target kbibtexgui_autogen
[ 59%] Built target kbibtexnetworkingtest
[ 80%] Built target kbibtexgui
[ 81%] Automatic MOC for target kbibtexpart
[ 81%] Automatic MOC for target kbibtex
[ 82%] Automatic MOC for target kbibtextest
AutoMoc warning:
  "/tmp/mfg-kbibtex-git-2390e60c06eb02156ed552f6b0b71b24/src/parts/part.cpp"
The file includes the moc file "part.moc", but does not contain a Q_OBJECT, Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY, K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or K_PLUGIN_CLASS_WITH_JSON macro.

[ 82%] Built target kbibtexpart_autogen
[ 82%] Built target kbibtex_autogen
[ 82%] Built target kbibtextest_autogen
[ 86%] Built target kbibtexpart
[ 89%] Built target kbibtextest
[100%] Built target kbibtex
Install the project...
-- Install configuration: "release"
-- Installing: /tmp/mfg-kbibtex-usr/etc/xdg/kbibtexrc
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/bibtex.kbstyle
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/biblatex.kbstyle
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/jabref_journalabbrevlist.txt
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0.9
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0.9" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/bin/kbibtex
-- Set runtime path of "/tmp/mfg-kbibtex-usr/bin/kbibtex" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/share/applications/org.kde.kbibtex.desktop
-- Installing: /tmp/mfg-kbibtex-usr/share/kxmlgui5/kbibtex/kbibtexui.rc
-- Installing: /tmp/mfg-kbibtex-usr/share/metainfo/org.kde.kbibtex.appdata.xml
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/128x128/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/16x16/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/22x22/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/32x32/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/48x48/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/share/icons/hicolor/64x64/apps/kbibtex.png
-- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/kbibtexpart.so
-- Set runtime path of "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/kbibtexpart.so" to "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
-- Installing: /tmp/mfg-kbibtex-usr/share/kservices5/kbibtexpart.desktop
-- Installing: /tmp/mfg-kbibtex-usr/share/kxmlgui5/kbibtexpart/kbibtexpartui.rc
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/fancy.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/standard.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/abstractonly.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/arxiv2bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/pubmed2bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/pam2bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/isbndb2bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/ieeexploreapiv1-to-bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/wikipedia-cite.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/worldcatdc2bibtex.xsl
-- Installing: /tmp/mfg-kbibtex-usr/share/mime/packages/bibliography.xml
-- Updating MIME database at /tmp/mfg-kbibtex-usr/share/mime
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/index.cache.bz2
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/index.docbook
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/add-macro-source.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/add-macro.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/application-pdf.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/applications-internet.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/code-context.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-color.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-general.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-id-suggestions.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-keywords.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-pdf.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-saving.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-user-interface.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/configure.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/cross-ref.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-open-remote.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-open.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-preview.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-revert.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-save.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/download.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/draw-text.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-clear-locationbar-rtl.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-element.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-undo.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/element-editor.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/external-tab.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/favorites.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/file-settings.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/filter-toolbar.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/find-pdf.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/first-run.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/flag.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/go-down.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/go-up.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-add.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-of-documents.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-of-values.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-remove.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/lyx-preferences.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/main-toolbar.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/media-playback-start.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/new-document.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/online-search.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/preferences-web-browser-identification.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/reference-preview.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/search-results.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/statistics.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/svn-update.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/tools-check-spelling.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/view-filter.png
-- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/zotero.png
-- Installing: /tmp/mfg-kbibtex-usr/share/man/man1/kbibtex.1
kbuildsycoca5 running...
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.systemmonitor.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.systemmonitor.desktop"
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.drkonqi.desktop"
kbibtex.program: Starting KBibTeX version "98402b78 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
"fe" ) , treating as comment
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
No Zotero credentials stored in KWallet
No Zotero credentials stored in KWallet
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
kf5.kxmlgui: 0x55975b0c3db0 deleted without having been removed from the factory first. This will leak standalone popupmenus and could lead to crashes.
QThreadStorage: Thread 0x559759121600 exited after QThreadStorage 13 destroyed
mfg@bix:~/sysi/com/down/kbibtex$

ups! crashed again
closed the program and opened it up again with

mfg@bix:~/sysi/com/down/kbibtex$ /tmp/mfg-kbibtex-usr/bin/kbibtex
kbibtex.program: Starting KBibTeX version "98402b78 (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
Empty filename for XSLT
kbibtex.networking: Failed to initialize XSL transformation based on file 'ieeexploreapiv1-to-bibtex.xsl'
kbibtex.networking: Generated XSLT filename was ' "kbibtex/ieeexploreapiv1-to-bibtex.xsl" '
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
No file found for ".xml" , even though update-mime-info said it would exist.
Either it was just removed, or the directory doesn't have executable permission... ("/home/mfg/.local/share/mime", "/usr/share/mime")
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
kf5.kio.core: KSambaShare: Could not find smb.conf!
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kbibtex path = /tmp/mfg-kbibtex-usr/bin pid = 26043
KCrash: Arguments: /tmp/mfg-kbibtex-usr/bin/kbibtex 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 /tmp/mfg-kbibtex-usr/bin/kbibtex
mfg@bix:~/sysi/com/down/kbibtex$

> If I change the four lines of the script run-kbibtex.sh near the beginning
> instead of /tmp with /usr/local/bin 
> in order to use the program without having to compile when I turn the
> machine off and on. Will it work? Is this a reasonable place to locate it?
It is technically possible although if you want to have a permanent storage location, I would rather recommend to use some directory inside your personal home directory.
For the variables below, simply replace
/tmp/${USER}-${APPLICATION}-
with
${HOME}/XXX/${APPLICATION}-
were XXX is a subdirectory of your choice. Keep the rest of the variables such as 'usr' as it is.

> GIT_DIRECTORY="/tmp/${USER}-${APPLICATION}-git-$(md5sum <<<"${GIT_URL}" |
> cut -f 1 -d ' ')"
> INSTALL_PREFIX="/tmp/${USER}-${APPLICATION}-usr"
> BUILD_DIRECTORY="/tmp/${USER}-${APPLICATION}-build-$(md5sum
> <<<"${GIT_URL}${GIT_BRANCH}" | cut -f 1 -d ' ')"
> XDG_DIRECTORY="/tmp/${USER}-${APPLICATION}-xdg-$(md5sum
> <<<"${GIT_URL}${GIT_BRANCH}" | cut -f 1 -d ' ')"
> 
> 
> --------------------------------
> This is the output of new installation:
> mfg@bix:~/sysi/com/down/kbibtex$ ./run-kbibtex.sh
> https://anongit.kde.org/kbibtex.git master
> Application:                  kbibtex
> Expected application binary:  /tmp/mfg-kbibtex-usr/bin/kbibtex
> Git URL:                      https://anongit.kde.org/kbibtex.git
> Git branch or tag:            master
> Installation prefix:          /tmp/mfg-kbibtex-usr
> Build directory:             
> /tmp/mfg-kbibtex-build-3274add80257946b78e6f19d1c4ff9b9
> Already on 'master'
> Your branch is up to date with 'origin/master'.
> Already up to date.
> -- Unity build disabled (default), use option UNITY_BUILD to enable it
> -- Poppler: Qt5 requires Core
> -- Found ICU 60.2.0
> -- Found Qca-qt5 2.1.3 and QtOAuth
> -- Found both QtWebEngine and QtWebKit, preferring to use QtWebEngine
> -- The following OPTIONAL packages have been found:
> 
>  * Qt5Qml (required version >= 5.9.5)
>  * Qt5Quick (required version >= 5.9.5)
>  * Qt5WebChannel (required version >= 5.9.5)
>  * Qt5Positioning (required version >= 5.9.5)
>  * Qt5WebEngineCore (required version >= 5.9.5)
>  * Qt5PrintSupport (required version >= 5.9.5)
>  * Qt5WebEngineWidgets (required version >= 5.6.0)
>  * Qt5WebKitWidgets (required version >= 5.6.0)
>  * KF5DocTools
>  * PkgConfig
>  * Qca-qt5 (required version >= 2.1.0)
>  * QtOAuth
>  * SharedMimeInfo, A database of common MIME types,
> <http://freedesktop.org/wiki/Software/shared-mime-info/>
> 
> -- The following REQUIRED packages have been found:
> 
>  * ECM (required version >= 5.19)
>  * Qt5Core
>  * Qt5Gui (required version >= 5.9.5)
>  * Qt5Widgets
>  * Qt5Network
>  * Qt5XmlPatterns
>  * Qt5Concurrent
>  * Qt5 (required version >= 5.6.0)
>  * Qt5Test (required version >= 5.6.0)
>  * Gettext
>  * PythonInterp
>  * KF5I18n (required version >= 5.26.0)
>  * KF5XmlGui (required version >= 5.26.0)
>  * KF5KIO (required version >= 5.26.0)
>  * KF5IconThemes (required version >= 5.26.0)
>  * KF5ItemViews (required version >= 5.26.0)
>  * KF5Completion (required version >= 5.26.0)
>  * KF5Parts (required version >= 5.26.0)
>  * KF5CoreAddons (required version >= 5.26.0)
>  * KF5Service (required version >= 5.26.0)
>  * KF5Wallet (required version >= 5.26.0)
>  * KF5Crash (required version >= 5.26.0)
>  * KF5 (required version >= 5.26.0)
>  * Poppler, A PDF rendering library, <http://poppler.freedesktop.org>
>  * ICU
> 
> -- Configuring done
> -- Generating done
> -- Build files have been written to:
> /tmp/mfg-kbibtex-build-3274add80257946b78e6f19d1c4ff9b9
> [  0%] Built target doc-index-cache-bz2
> [  1%] Automatic MOC for target kbibtexconfig
> [  1%] Built target doc-kbibtex-1
> [  1%] Built target kbibtexconfig_autogen
> [  4%] Built target kbibtexconfig
> [  5%] Automatic MOC for target kbibtexdata
> [  5%] Built target kbibtexdata_autogen
> [ 11%] Built target kbibtexdata
> [ 12%] Automatic MOC for target kbibtexdatatest
> [ 12%] Automatic MOC for target kbibtexio
> [ 12%] Built target kbibtexdatatest_autogen
> [ 12%] Built target kbibtexio_autogen
> [ 14%] Built target kbibtexdatatest
> [ 28%] Built target kbibtexio
> [ 28%] Automatic MOC for target kbibtexproc
> [ 29%] Automatic MOC for target kbibtexfilestest
> [ 30%] Automatic MOC for target kbibtexnetworking
> [ 30%] Automatic MOC for target kbibtexiotest
> [ 30%] Built target kbibtexproc_autogen
> [ 30%] Built target kbibtexiotest_autogen
> [ 30%] Built target kbibtexfilestest_autogen
> [ 30%] Built target kbibtexnetworking_autogen
> [ 35%] Built target kbibtexproc
> [ 37%] Built target kbibtexfilestest
> [ 39%] Built target kbibtexiotest
> [ 57%] Built target kbibtexnetworking
> [ 57%] Automatic MOC for target kbibtexnetworkingtest
> [ 57%] Automatic MOC for target kbibtexgui
> [ 57%] Built target kbibtexnetworkingtest_autogen
> [ 57%] Built target kbibtexgui_autogen
> [ 59%] Built target kbibtexnetworkingtest
> [ 80%] Built target kbibtexgui
> [ 81%] Automatic MOC for target kbibtextest
> [ 82%] Automatic MOC for target kbibtexpart
> [ 82%] Automatic MOC for target kbibtex
> AutoMoc warning:
>   "/tmp/mfg-kbibtex-git-2390e60c06eb02156ed552f6b0b71b24/src/parts/part.cpp"
> The file includes the moc file "part.moc", but does not contain a Q_OBJECT,
> Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY,
> K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or
> K_PLUGIN_CLASS_WITH_JSON macro.
> 
> [ 82%] Built target kbibtexpart_autogen
> [ 82%] Built target kbibtextest_autogen
> [ 82%] Built target kbibtex_autogen
> [ 86%] Built target kbibtexpart
> [ 89%] Built target kbibtextest
> [100%] Built target kbibtex
> [  1%] Automatic MOC for target kbibtexconfig
> [  1%] Built target doc-kbibtex-1
> [  1%] Built target doc-index-cache-bz2
> [  1%] Built target kbibtexconfig_autogen
> [  4%] Built target kbibtexconfig
> [  5%] Automatic MOC for target kbibtexdata
> [  5%] Built target kbibtexdata_autogen
> [ 11%] Built target kbibtexdata
> [ 12%] Automatic MOC for target kbibtexio
> [ 12%] Automatic MOC for target kbibtexdatatest
> [ 12%] Built target kbibtexdatatest_autogen
> [ 12%] Built target kbibtexio_autogen
> [ 14%] Built target kbibtexdatatest
> [ 28%] Built target kbibtexio
> [ 29%] Automatic MOC for target kbibtexnetworking
> [ 29%] Automatic MOC for target kbibtexproc
> [ 29%] Automatic MOC for target kbibtexiotest
> [ 30%] Automatic MOC for target kbibtexfilestest
> [ 30%] Built target kbibtexproc_autogen
> [ 30%] Built target kbibtexiotest_autogen
> [ 30%] Built target kbibtexnetworking_autogen
> [ 30%] Built target kbibtexfilestest_autogen
> [ 32%] Built target kbibtexiotest
> [ 37%] Built target kbibtexproc
> [ 39%] Built target kbibtexfilestest
> [ 57%] Built target kbibtexnetworking
> [ 57%] Automatic MOC for target kbibtexnetworkingtest
> [ 57%] Automatic MOC for target kbibtexgui
> [ 57%] Built target kbibtexnetworkingtest_autogen
> [ 57%] Built target kbibtexgui_autogen
> [ 59%] Built target kbibtexnetworkingtest
> [ 80%] Built target kbibtexgui
> [ 81%] Automatic MOC for target kbibtexpart
> [ 81%] Automatic MOC for target kbibtex
> [ 82%] Automatic MOC for target kbibtextest
> AutoMoc warning:
>   "/tmp/mfg-kbibtex-git-2390e60c06eb02156ed552f6b0b71b24/src/parts/part.cpp"
> The file includes the moc file "part.moc", but does not contain a Q_OBJECT,
> Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY,
> K_PLUGIN_CLASS_WITH_JSON, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY or
> K_PLUGIN_CLASS_WITH_JSON macro.
> 
> [ 82%] Built target kbibtexpart_autogen
> [ 82%] Built target kbibtex_autogen
> [ 82%] Built target kbibtextest_autogen
> [ 86%] Built target kbibtexpart
> [ 89%] Built target kbibtextest
> [100%] Built target kbibtex
> Install the project...
> -- Install configuration: "release"
> -- Installing: /tmp/mfg-kbibtex-usr/etc/xdg/kbibtexrc
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/bibtex.kbstyle
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/biblatex.kbstyle
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/kbibtex/jabref_journalabbrevlist.txt
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0.9
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexconfig.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0.9
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexdata.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0.9
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexio.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0.9
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexproc.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0.9
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexnetworking.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0.9
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0
> -- Installing: /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/libkbibtexgui.so.0.9" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing: /tmp/mfg-kbibtex-usr/bin/kbibtex
> -- Set runtime path of "/tmp/mfg-kbibtex-usr/bin/kbibtex" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/applications/org.kde.kbibtex.desktop
> -- Installing: /tmp/mfg-kbibtex-usr/share/kxmlgui5/kbibtex/kbibtexui.rc
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/metainfo/org.kde.kbibtex.appdata.xml
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/128x128/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/16x16/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/22x22/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/32x32/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/48x48/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/icons/hicolor/64x64/apps/kbibtex.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/kbibtexpart.so
> -- Set runtime path of
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu/plugins/kbibtexpart.so" to
> "/tmp/mfg-kbibtex-usr/lib/x86_64-linux-gnu"
> -- Installing: /tmp/mfg-kbibtex-usr/share/kservices5/kbibtexpart.desktop
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/kxmlgui5/kbibtexpart/kbibtexpartui.rc
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/fancy.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/standard.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/abstractonly.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/arxiv2bibtex.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/pubmed2bibtex.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/pam2bibtex.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/isbndb2bibtex.xsl
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/kbibtex/ieeexploreapiv1-to-bibtex.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/wikipedia-cite.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/kbibtex/worldcatdc2bibtex.xsl
> -- Installing: /tmp/mfg-kbibtex-usr/share/mime/packages/bibliography.xml
> -- Updating MIME database at /tmp/mfg-kbibtex-usr/share/mime
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/index.cache.bz2
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/index.docbook
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/add-macro-source.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/add-macro.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/application-pdf.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/applications-internet.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/code-context.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-color.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-general.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-id-suggestions.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-keywords.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-pdf.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-saving.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/config-user-interface.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/configure.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/cross-ref.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-open-remote.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-open.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-preview.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-revert.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/document-save.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/download.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/draw-text.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-clear-locationbar-rtl.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-element.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/edit-undo.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/element-editor.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/external-tab.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/favorites.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/file-settings.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/filter-toolbar.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/find-pdf.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/first-run.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/flag.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/go-down.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/go-up.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-add.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-of-documents.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-of-values.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/list-remove.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/lyx-preferences.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/main-toolbar.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/media-playback-start.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/new-document.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/online-search.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/preferences-web-browser-
> identification.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/reference-preview.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/search-results.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/statistics.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/svn-update.png
> -- Installing:
> /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/tools-check-spelling.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/view-filter.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/doc/HTML/en/kbibtex/zotero.png
> -- Installing: /tmp/mfg-kbibtex-usr/share/man/man1/kbibtex.1
> kbuildsycoca5 running...
> kf5.kservice.services: The desktop entry file
> "/usr/share/applications/org.kde.systemmonitor.desktop" has Type=
> "Application" but no Exec line
> kf5.kservice.sycoca: Invalid Service : 
> "/usr/share/applications/org.kde.systemmonitor.desktop"
> kf5.kservice.services: The desktop entry file
> "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application"
> but no Exec line
> kf5.kservice.sycoca: Invalid Service : 
> "/usr/share/applications/org.kde.drkonqi.desktop"
> kbibtex.program: Starting KBibTeX version "98402b78 (master)"
> QCommandLineParser: option not defined: "author"
> QCommandLineParser: option not defined: "license"
> QCommandLineParser: option not defined: "desktopfile"
> kbibtex.program: WebEngine is available, using it instead of WebKit or HTML
> KPart (both neither considered nor tested for) for HTML/Web preview.
> kbibtex.program: Located KPart service: "kbibtexpart" with description
> "KParts component to view and edit bibliographic files" from library
> "kbibtexpart"
> kf5.kio.core: KSambaShare: Could not find smb.conf!
> kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts
> component to view and edit bibliographic files" ) for mime type
> "text/x-bibtex" through library "kbibtexpart"
> kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
> kf5.kxmlgui: this does not work on a KActionCollection containing actions!
> kbibtex.io: BibUtils found, using it to import/export certain types of
> bibliographies
> kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
> kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts
> component to view and edit bibliographic files" ) for mime type
> "text/x-bibtex" through library "kbibtexpart"
> kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
> kf5.kxmlgui: this does not work on a KActionCollection containing actions!
> kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
> "fe" ) , treating as comment
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.parts: Creating KBibTeX Part of version "98402b78 (master)"
> kf5.kxmlgui: this does not work on a KActionCollection containing actions!
> kbibtex.io: Unknown token ' 'e' ( "0x0065" ) ' near line  1140 ( "" 
> "fe" ) , treating as comment
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> No Zotero credentials stored in KWallet
> No Zotero credentials stored in KWallet
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> kbibtex.program: Found library for "text/x-bibtex" : "kbibtexpart"
> kbibtex.program: Found library for "text/x-bibtex" : "kf5/parts/katepart"
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> QWidget::insertAction: Attempt to insert null action
> kf5.kxmlgui: 0x55975b0c3db0 deleted without having been removed from the
> factory first. This will leak standalone popupmenus and could lead to
> crashes.
> QThreadStorage: Thread 0x559759121600 exited after QThreadStorage 13
> destroyed
> mfg@bix:~/sysi/com/down/kbibtex$

> kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
> KCrash: crashing... crashRecursionCounter = 2
> KCrash: Application Name = kbibtex path = /tmp/mfg-kbibtex-usr/bin pid = 26043
> KCrash: Arguments: /tmp/mfg-kbibtex-usr/bin/kbibtex 
> KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
> sock_file=/run/user/1000/kdeinit5__0
Didn't you get any crash report from DrKonqi?

In case DrKonqi does not work here, in run-kbibtex.sh at the script's end, disable this line
( cd ${HOME} && ${INSTALL_PREFIX}/bin/${APPLICATION} ) || exit 1
and enable this line:
( cd ${HOME} && valgrind --error-limit=no --smc-check=all-non-file --track-origins=yes --log-file=/tmp/${USER}-${APPLICATION}-valgrind-$(date '+%Y%m%d-%H%M%S').txt --show-reachable=yes --num-callers=24 -v --leak-check=full ${INSTALL_PREFIX}/bin/${APPLICATION} ) || exit 1

This will generate a log file with name pattern /tmp/*-valgrind-*.txt. As the file will be very large, please compress it with gzip or xz before submitting it here.

Created attachment 115972 [details]
crash when restarting kbibtex

here is the crash file generated by Dr. Konqi

However, I found that:
If I go to the directory where the executable is:
mfg@bix:/tmp/mfg-kbibtex-usr/bin$ 
and run 'kbibtex' there, everything works fine.

If from any other directory, say mfg@bix: I run /tmp/mfg-kbibtex-usr/bin/kbibtex
then the program crashes when I open an entry.

Are you mixing a self-compiled Kile with a system-installed Kile? If you type "kile" at the prompt, without a path, it will not start kile from the current directory, but from the system directories (unless you have current directory in your $PATH before system directories).

You are right Christopher. I was running the installed kbibtex in the latter case.

What remains true is that if I start the program by compiling it with Fisher's script (attachment 115934 [details]), the program launches automatically and works fine.
However, upon closing and opening the program again with

/tmp/mfg-kbibtex-usr/bin/kbibtex

 it crashes as mentioned before.

Is '/tmp/mfg-kbibtex-usr/bin/kbibtex' a script that sets the needed environment or just the compiled executable?

(In reply to Christoph Feck from comment #55)
> Is '/tmp/mfg-kbibtex-usr/bin/kbibtex' a script that sets the needed
> environment or just the compiled executable?

Thomas Fisher kindly prepared the script. So he is the one who knows.
However, if I understand correctly, the answer to your question is that it is the compiled executable.

Hello,

(In reply to manuel fernández from comment #56)
> (In reply to Christoph Feck from comment #55)
> > Is '/tmp/mfg-kbibtex-usr/bin/kbibtex' a script that sets the needed
> > environment or just the compiled executable?
> Thomas Fisher kindly prepared the script. So he is the one who knows.
> However, if I understand correctly, the answer to your question is that it
> is the compiled executable.
The script run-kbibtex.sh (attachment 115934 [details]) fetches the latest code from Git, configures and complies it, as well as launches KBibTeX. Important is that it sets some environment variables (within the script, not globally nor permanently) to use the correct directories and libraries when launching the binary.
That is why launching the binary directly from command line is bound to fail as either no libraries or the wrong libraries are found/used.
A recent crash report (attachment 115972 [details]) showed that at the time of the crash KBibTeX libraries from /tmp/mfg-kbibtex-usr/lib and /usr/lib/x86_64-linux-gnu/qt5/plugins/kbibtexpart.so got mixed -- a recipe for disaster.

tl;dr: Launch KBibTeX only via run-kbibtex.sh (attachment 115934 [details]) if trying to reproduce this crash. If that instance of KBibTeX does not crash, there is no bug.

The script run-kbibtex.sh (attachment 115934 [details]) works properly.
The program does not crash and opens files, rather slowly and operations take longer than usual. But otherwise works fine!

tail of output is:
-- Installing: /home/mfg/sysi/com/down/kbib/mfg-kbibtex-usr/share/man/man1/kbibtex.1
kbuildsycoca5 running...
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.systemmonitor.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.systemmonitor.desktop"
kf5.kservice.services: The desktop entry file "/usr/share/applications/org.kde.drkonqi.desktop" has Type= "Application" but no Exec line
kf5.kservice.sycoca: Invalid Service :  "/usr/share/applications/org.kde.drkonqi.desktop"
kbibtex.program: Starting KBibTeX version "f3040c9c (master)"
QCommandLineParser: option not defined: "author"
QCommandLineParser: option not defined: "license"
QCommandLineParser: option not defined: "desktopfile"
kbibtex.io: Generated XSLT filename is  "/usr/share/kbibtex/arxiv2bibtex.xsl"  for stem  "arxiv2bibtex.xsl"
kbibtex.io: Generated XSLT filename is  "/home/mfg/sysi/com/down/kbib/mfg-kbibtex-usr/share/kbibtex/ieeexploreapiv1-to-bibtex.xsl"  for stem  "ieeexploreapiv1-to-bibtex.xsl"
kbibtex.io: Generated XSLT filename is  "/usr/share/kbibtex/pubmed2bibtex.xsl"  for stem  "pubmed2bibtex.xsl"
kbibtex.io: Generated XSLT filename is  "/usr/share/kbibtex/pam2bibtex.xsl"  for stem  "pam2bibtex.xsl"
kbibtex.program: WebEngine is available, using it instead of WebKit or HTML KPart (both neither considered nor tested for) for HTML/Web preview.
Trying to convert empty KLocalizedString to QString.
kbibtex.program: Located KPart service: "kbibtexpart" with description "KParts component to view and edit bibliographic files" from library "kbibtexpart"
kbibtex.io: BibUtils found, using it to import/export certain types of bibliographies
kbibtex.program: Using service "BibTeX Viewer and Editor" ( "KParts component to view and edit bibliographic files" ) for mime type "text/x-bibtex" through library "kbibtexpart"
kbibtex.parts: Creating KBibTeX Part of version "f3040c9c (master)"
kf5.kxmlgui: this does not work on a KActionCollection containing actions!
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
kbibtex.io: Don't know how to translate this into Unicode:  "\\mu"
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
kf5.kxmlgui: 0x55e1b1887af0 deleted without having been removed from the factory first. This will leak standalone popupmenus and could lead to crashes.
mfg@bix:~/sysi/com/down/kbibtex$

(In reply to manuel fernández from comment #58)
> The script run-kbibtex.sh (attachment 115934 [details]) works properly.
> The program does not crash and opens files, rather slowly and operations
> take longer than usual. But otherwise works fine!
Being slow? Just checking, are you using the line with 'valgrind' at the end of the script?

I just checked the run-kbibtex.sh 
I am not using the valgrind alternative (It is greyed out with ## in front of this line)

(In reply to manuel fernández from comment #60)
> I just checked the run-kbibtex.sh 
> I am not using the valgrind alternative (It is greyed out with ## in front
> of this line)
This may be an unrelated issue. At least the crash that were the reason for the original report no longer exists.

Thank you, great work!

Git commit 0a66597728d194a3ad2ceadbbfa06cc317e68105 by Thomas Fischer.
Committed on 20/11/2018 at 19:58.
Pushed by thomasfischer into branch 'kbibtex/0.8'.

Adding robustness and verbosity when locating KParts

- Adding both comments and debug output in code sections on locating KParts
  used to edit bibliography files.
- Addressing bug where code depended on a valid return value of QList::last()
  not considering that the list may be empty.

M  +32   -12   src/program/openfileinfo.cpp

https://commits.kde.org/kbibtex/0a66597728d194a3ad2ceadbbfa06cc317e68105