Bug 407642

Summary:	KFileWidget selects the the wrong filter on filter change with enabled automatic extensions
Product:	[Frameworks and Libraries] frameworks-kio	Reporter:	Jan-Marek Glogowski <glogow>
Component:	Open/save dialogs	Assignee:	David Faure <faure>
Status:	RESOLVED FIXED
Severity:	normal	CC:	kdelibs-bugs, m.weghorn, nate
Priority:	NOR
Version:	5.54.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:	https://commits.kde.org/kio/c4e90b5a6bf41816b2938dc2df4820e56ed6e42e	Version Fixed In:
Sentry Crash Report:
Attachments:	Simple test file picker program qmake file

Description Jan-Marek Glogowski 2019-05-17 13:18:23 UTC

Created attachment 120135 [details]
Simple test file picker program

If your filter list has two matching filters for an extension, KFileWidget will always select the first filter, even if the current filter already matches the file name.

The result is that a user selects a filter and it's not honored by the UI. This resulted in two bugs in LibreOffice with the KDE backend:

* https://bugs.documentfoundation.org/show_bug.cgi?id=125267
* https://bugs.documentfoundation.org/show_bug.cgi?id=120950

Our workaround is now to ignore the returned filter string.
This bug doesn't happen with the non-native QFileDialog.

STEPS TO REPRODUCE
1. Compile and run the attached program
2. Make sure that "auto extension" checkbox is enable
2. Select the last file filter (DocBook (.xml)) via dropdown list

OBSERVED RESULT
Filter is "Word 2003 XML (.xml)"

EXPECTED RESULT
Filter is "DocBook (.xml)"

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian Buster with KIO 5.54

I already have a patch for this.

Comment 1 Jan-Marek Glogowski 2019-05-17 13:34:52 UTC

Created attachment 120136 [details]
qmake file

Comment 2 Jan-Marek Glogowski 2019-05-17 14:25:45 UTC

Patch: https://phabricator.kde.org/D21249

Comment 3 Nate Graham 2019-05-21 19:49:31 UTC

Git commit c4e90b5a6bf41816b2938dc2df4820e56ed6e42e by Nate Graham, on behalf of Jan-Marek Glogowski.
Committed on 21/05/2019 at 19:49.
Pushed by ngraham into branch 'master'.

Test current filter before setting a new one

Summary:
If KFileWidget's filter list has two matching filters for an extension,
it will always select the first filter, even if the current filter
already matches the file name.

This is fine, if you auto-select the filter to match the file name, but
breaks, if you want to auto-change the file name's extension via the
selected filter.

So this checks, if the current filter already matches the file name
before trying to find a matching filter and select it.

Test Plan:
1. Compile and run the attached program to the bug report 407642
2. Make sure that "auto extension" checkbox is enable
2. Select the last file filter (DocBook (.xml)) via dropdown list

OBSERVED RESULT
Filter is "Word 2003 XML (.xml)"

EXPECTED RESULT
Filter is "DocBook (.xml)"

Reviewers: #frameworks, ngraham, dfaure

Reviewed By: dfaure

Subscribers: elvisangelaccio, ngraham, michaelweghorn, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D21249

M  +63   -0    autotests/kfilewidgettest.cpp
M  +23   -9    src/filewidgets/kfilewidget.cpp

https://commits.kde.org/kio/c4e90b5a6bf41816b2938dc2df4820e56ed6e42e

Comment 4 Michael Weghorn 2019-05-22 08:10:13 UTC

Thanks for the fix!

I just retested and while the issue reported here is gone, the original LibrOffice use case is unfortunately still not working. I created follow-up bug report bug 407819 for this (correct filter is displayed, but not returned when calling 'QFileDialog::selectedNameFilter'.

(I tested with kio version 5.54 from Debian testing + the patch on top, since master branch has more dependencies not fulfilled in Debian testing).