Skip to content

Handle exceptions during SkiaSwingLayer rendering#816

Open
Walingar wants to merge 1 commit intomasterfrom
nr/swing-interop-repaint-exceptions
Open

Handle exceptions during SkiaSwingLayer rendering#816
Walingar wants to merge 1 commit intomasterfrom
nr/swing-interop-repaint-exceptions

Conversation

@Walingar
Copy link
Copy Markdown
Contributor

@Walingar Walingar requested review from igordmn and m-sasha October 23, 2023 10:31
@m-sasha
Copy link
Copy Markdown
Contributor

m-sasha commented Oct 23, 2023

I'm usually against catching exceptions like that unless there's a very good reason (like maybe if you're controlling a nuclear reactor). It's better to even crash the process because then the exception is noticed and fixed faster. I only recommend catching exceptions if they're thrown by a 3rd-party black-box, which can't be fixed.

repaint()
}
} catch (e: Exception) {
Logger.warn(e) { "Exception during SkiaSwingLayer rendering" }
Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@m-sasha I agree, but I would say that this part of the framework is crucial, so not handling exceptions here would cause completely broken view (like in attached issue)

Copy link
Copy Markdown
Contributor

@m-sasha m-sasha Oct 23, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

But why would there be exceptions here? Is it not better to discover and fix them instead?
In Compose we catch exceptions at the window level and typically show an error dialog followed by shutting down the application. Why is that not a good policy here?

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

They can appear only because of the broken internal contracts (out mistakes) and for sure they should be fixed. Like here JetBrains/compose-multiplatform-core#878

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Then we should introduce this policy for swing bridge then too. Do you think it would be better?

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I would recommend that, yes. I wonder what @igordmn thinks.

Copy link
Copy Markdown
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We had similar code in the past (try-catch-log for rendering), and it was bad UX for end users (the window just stops to draw). We moved exception handling responsibility to SkikoView, as exceptions happen on its level, and it knows what to do with it.

In case of Swing components (which ComposePanel is), what is the policy for exceptions during rendering?

Regarding what policy we choose, we should implement it on the ComposeBridge level. Actually it is already implemented (see ComposePanel.exceptionHandler), we just need to define the default behavior.

Copy link
Copy Markdown
Contributor

@m-sasha m-sasha Nov 7, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In case of Swing components (which ComposePanel is), what is the policy for exceptions during rendering?

Looks like it just calls the thread's uncaught exception handler (from EventDispatchThread.pumpOneEventForFilters). The default handler just prints the stack trace to stderr.

Copy link
Copy Markdown
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If that is the case, it seems everything already works this way?

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Only by default (which I also think is a bad idea). In Swing I can set the thread's uncaught exception handler and change the behavior.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants