Bug 513914 - Kdiff3 crashes on first add manual diff alignment in a file
Summary: Kdiff3 crashes on first add manual diff alignment in a file
Status: REPORTED
Alias: None
Product: kdiff3
Classification: Applications
Component: application (other bugs)
Version First Reported In: 1.12.3
Platform: Fedora RPMs Linux
: NOR crash
Target Milestone: ---
Assignee: michael
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-12-28 14:55 UTC by Håkon Løvdal
Modified: 2026-01-06 14:47 UTC (History)
0 users

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:

Attachments
Input file 1 (459 bytes, text/plain)
2025-12-28 14:55 UTC, Håkon Løvdal 		Details
Input file 2 (329 bytes, text/plain)
2025-12-28 14:56 UTC, Håkon Løvdal 		Details
Input file 3 (1.58 KB, text/plain)
2025-12-28 14:56 UTC, Håkon Løvdal 		Details
DrKonqi crash report (70.26 KB, text/plain)
2025-12-28 14:59 UTC, Håkon Løvdal 		Details
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Description Håkon Løvdal 2025-12-28 14:55:51 UTC 
Created attachment 188035 [details]
Input file 1

SUMMARY

Kdiff3 crashes on first add manual diff alignment in file1.

STEPS TO REPRODUCE

1. Launch `kdiff3 -o out file1 file2 file3`.
2. Click ok on number of conflicts dialog.
3. Select the first character on line 14 in file1.
4. Press Ctrl-Y (add manual diff alignment)
5. KDiff3 crashes.

OBSERVED RESULT

Stdout/stderr from the crash:

/usr/include/c++/15/bits/stl_vector.h:1263: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = Diff3WrapLine; _Alloc = std::allocator<Diff3WrapLine>; reference = Diff3WrapLine&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.
KCrash: Application 'kdiff3' crashing... crashRecursionCounter = 2

EXPECTED RESULT

No crash.

SOFTWARE/OS VERSIONS

Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.21.0
Qt Version: 6.10.1
Kernel Version: 6.17.12-300.fc43.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i5-10500H CPU @ 2.50GHz
Memory: 64 GiB of RAM (62.6 GiB usable)
Graphics Processor: Intel® UHD Graphics

ADDITIONAL INFORMATION
Comment 1 Håkon Løvdal 2025-12-28 14:56:24 UTC 
Created attachment 188036 [details]
Input file 2
Comment 2 Håkon Løvdal 2025-12-28 14:56:45 UTC 
Created attachment 188037 [details]
Input file 3
Comment 3 Håkon Løvdal 2025-12-28 14:59:03 UTC 
Created attachment 188038 [details]
DrKonqi crash report
Comment 4 michael 2026-01-06 14:47:55 UTC 
This does not seem to reproduce on my system but it is not clear why.