~/.kde4/share/config/kmail2rc contains:
[$Version]
update_info=kmail.upd:1,kmail.upd:4,kmail.upd:5,kmail.upd:6,kmail.upd:7,kmail.upd:8,kmail.upd:9,kmail.upd:3.1-update-identities,kmail.upd:3.1-use-identity-uoids,kmail.upd:3.2-update-loop-on-goto-unread-settings,kmail.upd:3.1.4-dont-use-UOID-0-for-any-identity,kmail.upd:3.2-misc,kmail.upd:3.2-moves,kmail.upd:3.3-use-ID-for-accounts,kmail.upd:3.3-update-filter-rules,kmail.upd:3.3-misc,kmail.upd:3.3b1-misc,kmail.upd:3.4,kmail.upd:3.4a,kmail.upd:3.4b,kmail.upd:3.4.1,kmail.upd:3.5.4,kmail.upd:3.5.7-imap-flag-migration,kmail.upd:4.0-misc,kmail.upd:4.2

Created attachment 53731 [details]
Patch that adds some debug statements for further debugging

I started kmail-migrator remotely and get the following output with the patch from Tobias. The return code is still 3 - but there no error shown.

$ /usr/bin/kmail-migrator --interactive-on-change
kmail-migrator(18351)/libakonadi Akonadi::AgentManagerPrivate::createDBusInterface: AgentManager failed to get a valid AgentManager DBus interface. Error is: 1 "org.freedesktop.DBus.Error.NameHasNoOwner" "Could not get owner of name 'org.freedesktop.Akonadi.Control': no such name" 
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
search paths:  ("/suse/aj/bin", "/suse/aj/bin", "/suse/aj/bin", "/usr/local/bin", "/usr/bin", "/bin", "/usr/bin/X11", "/usr/X11R6/bin", "/usr/games", "/opt/kde3/bin", "/usr/lib64/jvm/jre/bin", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") 
Found mysql_install_db:  "/usr/bin/mysql_install_db" 
Found mysqlcheck:  "/usr/bin/mysqlcheck" 
QSqlDatabasePrivate::removeDatabase: connection 'initConnection' is still in use, all queries will cease to work.
Database "akonadi" opened using driver "QMYSQL" 
DbInitializer::run() 
checking table  "SchemaVersionTable" 
checking table  "ResourceTable" 
checking table  "CollectionTable" 
checking table  "MimeTypeTable" 
checking table  "PimItemTable" 
checking table  "FlagTable" 
checking table  "PartTable" 
checking table  "CollectionAttributeTable" 
checking relation  "PimItemFlagRelation" 
checking relation  "CollectionMimeTypeRelation" 
checking relation  "CollectionPimItemRelation" 
DbInitializer::run() done 
skipping update 2 
skipping update 3 
skipping update 4 
skipping update 8 
skipping update 10 
skipping update 12 
skipping update 13 
skipping update 14 
skipping update 15 
skipping update 16 
skipping update 17 
skipping update 18 
skipping update 19 
Nepomuk Query Server not available 
DataStore::unhideAllPimItems() 
Database "akonadi" opened using driver "QMYSQL" 
Database "akonadi" opened using driver "QMYSQL" 
PLUGINS:  "/usr/share/akonadi/agents" 
PLUGINS:  ("akonotesresource.desktop", "birthdaysresource.desktop", "calendarsearchagent.desktop", "contactsresource.desktop", "davgroupwareresource.desktop", "icalresource.desktop", "imapresource.desktop", "invitationsagent.desktop", "kabcresource.desktop", "kcalresource.desktop", "kdeaccountsresource.desktop", "kolabproxyresource.desktop", "localbookmarksresource.desktop", "maildirresource.desktop", "maildispatcheragent.desktop", "mboxresource.desktop", "microblog.desktop", "mixedmaildirresource.desktop", "mtdummyresource.desktop", "nepomukcalendarfeeder.desktop", "nepomukcontactfeeder.desktop", "nepomukemailfeeder.desktop", "nepomuktagresource.desktop", "nntpresource.desktop", "notesresource.desktop", "openxchangeresource.desktop", "pop3resource.desktop", "strigifeeder.desktop", "vcarddirresource.desktop", "vcardresource.desktop") 
search paths:  ("/suse/aj/bin", "/suse/aj/bin", "/suse/aj/bin", "/usr/local/bin", "/usr/bin", "/bin", "/usr/bin/X11", "/usr/X11R6/bin", "/usr/games", "/opt/kde3/bin", "/usr/lib64/jvm/jre/bin") 
PLUGINS inserting:  "akonadi_akonotes_resource" 2 ("Resource", "Notes") 
PLUGINS inserting:  "akonadi_birthdays_resource" 0 ("Resource", "Unique") 
PLUGINS inserting:  "akonadi_calendarsearch_agent" 0 ("Unique", "NoConfig") 
PLUGINS inserting:  "akonadi_contacts_resource" 1 ("Resource") 
PLUGINS inserting:  "akonadi_davgroupware_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_ical_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_imap_resource" 2 ("Resource") 
PLUGINS inserting:  "akonadi_invitations_agent" 0 ("NoConfig") 
PLUGINS inserting:  "akonadi_kabc_resource" 6 ("Resource") 
PLUGINS inserting:  "akonadi_kcal_resource" 1 ("Resource") 
PLUGINS inserting:  "akonadi_kdeaccounts_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_kolabproxy_resource" 0 ("Resource", "Unique") 
PLUGINS inserting:  "akonadi_localbookmarks_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_maildir_resource" 3 ("Resource") 
PLUGINS inserting:  "akonadi_maildispatcher_agent" 0 ("Unique", "Autostart", "NoConfig") 
PLUGINS inserting:  "akonadi_mbox_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_microblog_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_mixedmaildir_resource" 1 ("Resource") 
PLUGINS inserting:  "akonadi_mailtransport_dummy_resource" 0 ("Resource", "MailTransport") 
PLUGINS inserting:  "akonadi_nepomuk_calendar_feeder" 0 ("Unique", "Autostart", "NoConfig") 
PLUGINS inserting:  "akonadi_nepomuk_contact_feeder" 0 ("Unique", "Autostart", "NoConfig") 
PLUGINS inserting:  "akonadi_nepomuk_email_feeder" 0 ("Unique", "Search", "Autostart") 
PLUGINS inserting:  "akonadi_nepomuktag_resource" 0 ("Resource", "Virtual", "Unique", "NoConfig") 
PLUGINS inserting:  "akonadi_nntp_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_notes_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_openxchange_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_pop3_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_strigi_feeder" 0 ("Unique") 
PLUGINS inserting:  "akonadi_vcarddir_resource" 0 ("Resource") 
PLUGINS inserting:  "akonadi_vcard_resource" 0 ("Resource") 
AgentServer not up (yet?) 
AgentServer not up (yet?) 
AgentServer not up (yet?) 
Akonadi server is now operational. 
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
tokoe: InfoDialog::message(2)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(0)
tokoe: InfoDialog::message: mError=0
Database "akonadi" opened using driver "QMYSQL" 
Database "akonadi" opened using driver "QMYSQL" 
Database "akonadi" opened using driver "QMYSQL" 
Database "akonadi" opened using driver "QMYSQL" 
Database "akonadi" opened using driver "QMYSQL" 
Known subscriber "akonadi_maildispatcher_agent" subscribes again 
Known subscriber "akonadi_maildispatcher_agent" subscribes again 
Database "akonadi" opened using driver "QMYSQL" 
Known subscriber "akonadi_birthdays_resource" subscribes again 
Database "akonadi" opened using driver "QMYSQL" 
"/usr/bin/akonadi_nepomuk_contact_feeder(18389)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_calendar_feeder(18388)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_calendar_feeder(18388)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_contact_feeder(18389)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_calendar_feeder(18388)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_contact_feeder(18389)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
Database "akonadi" opened using driver "QMYSQL" 
"/usr/bin/akonadi_nepomuk_email_feeder(18390)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_email_feeder(18390)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
"/usr/bin/akonadi_nepomuk_email_feeder(18390)" Soprano: "org.freedesktop.DBus.Error.ServiceUnknown - The name org.kde.nepomuk.services.nepomukstorage was not provided by any .service files"
Database "akonadi" opened using driver "QMYSQL" 
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
Database "akonadi" opened using driver "QMYSQL" 
kbuildsycoca4 running...
Database "akonadi" opened using driver "QMYSQL" 
akonadi_kabc_resource_5(18384)/kio (KDirWatch) KDirWatchPrivate::removeEntry: doesn't know "/suse/aj/.kde4/share/apps/kabc" 
Database "akonadi" opened using driver "QMYSQL" 
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
QDBusConnection: name 'org.kde.kwalletd' had owner '' but we thought it was ':1.23'
Database "akonadi" opened using driver "QMYSQL" 
kwalletd(18454) KWalletD::setupDialog: Application ' "Akonadi Resource" ' using kwallet without parent window! 
QSystemTrayIcon::setVisible: No Icon set
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
tokoe: InfoDialog->hasError()=1

Second invocation:
$ /usr/bin/kmail-migrator --interactive-on-change
tokoe: InfoDialog::message(2)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(0)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog->hasError()=1
$ echo $?
3

Debugging I see:
(gdb) r
Starting program: /usr/bin/kmail-migrator --interactive-on-change
[Thread debugging using libthread_db enabled]
Detaching after fork from child process 18789.

Breakpoint 1, InfoDialog::message (this=0x7c07d0, type=KMigratorBase::Info, msg=...)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:75
75	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) p mError 
$3 = false
(gdb) c
Continuing.
tokoe: InfoDialog::message(2)
tokoe: InfoDialog::message: mError=0

Breakpoint 1, InfoDialog::message (this=0x7c07d0, type=KMigratorBase::Skip, msg=...)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:75
75	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) p mError 
$4 = false
(gdb) c
Continuing.
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0

Breakpoint 1, InfoDialog::message (this=0x7c07d0, type=KMigratorBase::Skip, msg=...)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:75
75	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) p mError 
$5 = false
(gdb) c
Continuing.
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0

Breakpoint 1, InfoDialog::message (this=0x7c07d0, type=KMigratorBase::Success, msg=...)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:75
75	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) p mError 
$6 = false
(gdb) c
Continuing.
tokoe: InfoDialog::message(0)
tokoe: InfoDialog::message: mError=0
^C
Program received signal SIGINT, Interrupt.
0x00007ffff41ce358 in poll () from /lib64/libc.so.6
(gdb) b InfoDialog::~InfoDialog
Breakpoint 2 at 0x448dc0: file /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp, line 69. (2 locations)
(gdb) c
Continuing.

Breakpoint 2, InfoDialog::~InfoDialog (this=0x7c07d0, __in_chrg=<value optimized out>)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:69
69	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) c
Continuing.

Breakpoint 2, InfoDialog::~InfoDialog (this=0x7c07d0, __in_chrg=<value optimized out>)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp:69
69	in /usr/src/debug/kdepim-runtime-4.5.80/migration/infodialog.cpp
(gdb) c
Continuing.
tokoe: InfoDialog->hasError()=1

Do we call InfoDialog after calling the destructor?

I guess I found it:
Breakpoint 4, main (argc=2, argv=0x7fffffffdfc8)
    at /usr/src/debug/kdepim-runtime-4.5.80/migration/kmail/main.cpp:83
83	in /usr/src/debug/kdepim-runtime-4.5.80/migration/kmail/main.cpp
(gdb) p infoDialog 
$8 = (InfoDialog *) 0x7c07d0
(gdb) p *infoDialog 
$9 = {<KDialog> = {<No data fields>}, static staticMetaObject = {d = {superdata = 0x690840, stringdata = 
    0x475280 "InfoDialog", data = 0x4753c0, extradata = 0x0}}, mList = 0x7b9c30, mStatusLabel = 
    0x7bba20, mProgressBar = 0x7b65a0, mMigratorCount = 1, mError = false, mChange = false, 
  mCloseWhenDone = true, mAutoScrollList = true}
(gdb) n
tokoe: InfoDialog::message(2)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(1)
tokoe: InfoDialog::message: mError=0
tokoe: InfoDialog::message(0)
tokoe: InfoDialog::message: mError=0
84	in /usr/src/debug/kdepim-runtime-4.5.80/migration/kmail/main.cpp
(gdb) p *infoDialog 
$10 = {<KDialog> = {<No data fields>}, static staticMetaObject = {d = {superdata = 0x690840, 
      stringdata = 0x475280 "InfoDialog", data = 0x4753c0, extradata = 0x0}}, mList = 
    0x4545454545454545, mStatusLabel = 0x4545454545454545, mProgressBar = 0x4545454545454545, 
  mMigratorCount = 1162167621, mError = 69, mChange = 69, mCloseWhenDone = 69, mAutoScrollList = 69}

so, we access in line 84:
    82   args->clear();
     83   const int result = app->exec();
     84   if ( infoDialog && infoDialog->hasError() )
     85     return 3;
     86   return result;
infoDialog but the destructor has been called already

Hej Andreas,

thanks for the deeper investigation of this issue. The problem was a deleteLater() call on the dialog when the 'Close' button is clicked.
I have removed this call in commit r1200805, so the dialog object should
be valid until hasError() is called.

Ciao,
Tobias

Thanks Tobias, this fixes it indeed!