4.7 Widget Blueprint crashes when opening editor

Development Platform & Builds
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1

This crash occurs when using the 4.7 branch on my Linux Mint build. After completing the build and invoking the UE4Editor, I created a project using the Blank project template. I then added a User Interface->Widget Blueprint to my Content and upon opening(double clicking) the “NewWidgetBlueprint”, UE4 crashes. I have attached zip of the crash report. Additionally I compiled and ran this in the debugger and was able to see that it is crashing in the…

FSequencerTimeSliderController::OnPaintTimeSlider function calling TimeSliderArgs.CursorSize.Get()

The line, 264 at this time, of the crash is as follows…

const float CursorHalfSize = TimeSliderArgs.CursorSize.Get() * 0.5f;

crashinfo-myproject13

2

Identical crash with same context on Ubuntu 14.04.

3

The same here, running Fedora-21-x86_64 KDE Plasma Workspace.
Moreover, this solution doesn’t work.

4

I have submitted a pull request that fixes this bug. Basically the problem was caused by two shared libraries containing the same symbols. In this case, the FSequencerTimeSliderController and SSequencerSectionOverlay classes were part of the Developer/LogVisualizer and the Editor/Sequence modules. Since these classes were not in their own namespace, the dynamic loader improperly resolved the dependency. To fix the problem, I renamed the duplicate classes in the Developer/LogVisualizer/private module and renamed the associated files for clarity. I also renamed the same files in the Editor/Sequencer/private module for consistency sake.

This problem makes me wonder if there are other duplicate classes that would be resolved improperly on Linux or other Unix-like platforms. This type of bug is usually really nasty to find and fix. Perhaps namespaces could help eliminate this kind of problem.

5

Hey CodeTackler-

Thanks for submitting a pull request for this problem. Our engineers will review the pull request and decide whether to include it into the source.

Cheers

6

Thanks CodeTackler! Your fix works like a charm!