ErrorDialogue : Fix parentWindow lifetime issues #1986
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Because ErrorDialogue.ErrorHandler was deriving from IECore.MessageHandler, it was subject to garbage collection. When used from the FileMenu (and others), the parentWindow passed was a full blown ScriptWindow, which in turn became subject to garbage collection. Garbage collection can kick in at any time, and on any thread. This could lead to a ScriptWindow being destroyed on a non-gui thread, leading to the attempted destruction of QtOpenGL resources on the wrong thread, and therefore deadlocks and crashes. We fix this by changing the ErrorHandler/MessageHandler relationship from "is a" to "has a", which is arguably what it should have been anyway, even without lifetime considerations.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Because ErrorDialogue.ErrorHandler was deriving from IECore.MessageHandler, it was subject to garbage collection. When used from the FileMenu (and others), the parentWindow passed was a full blown ScriptWindow, which in turn became subject to garbage collection. Garbage collection can kick in at any time, and on any thread. This could lead to a ScriptWindow being destroyed on a non-gui thread, leading to the attempted destruction of QtOpenGL resources on the wrong thread, and therefore deadlocks and crashes.
We fix this by changing the ErrorHandler/MessageHandler relationship from "is a" to "has a", which is arguably what it should have been anyway, even without lifetime considerations.