Fix Application Freeze by Dispatching DisplayLink Updates to Main Thread#3
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rojinc wants to merge 1 commit intojpomykala:mainfrom
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Fix Application Freeze by Dispatching DisplayLink Updates to Main Thread#3rojinc wants to merge 1 commit intojpomykala:mainfrom
rojinc wants to merge 1 commit intojpomykala:mainfrom
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Ensure timestamp is sent on the main thread.
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Pull request overview
This PR fixes a critical application freeze issue caused by thread-safety violations in the display refresh callback. The CVDisplayLink callback executes on a background thread but was directly sending values to a Combine subject that triggers UI updates, leading to main thread deadlocks.
Changes:
- Wrapped the subject emission in
DispatchQueue.main.asyncwithin the CVDisplayLink callback to ensure thread-safe UI updates
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This PR addresses a critical bug where the application would freeze, forcing users to force-quit via Activity Monitor.
The root cause was identified in PrompterViewModel.swift. The CVDisplayLink callback runs on a background thread, but it was directly sending values to a Combine subject that triggers UI updates. Updating the UI from a background thread is undefined behavior in macOS/iOS development and led to the main thread deadlock.
This fix wraps the subject emission in DispatchQueue.main.async to ensure all UI-related updates occur safely on the main thread.
Changes
PrompterViewModel.swift: Wrapped ref.subject.send(ts) inside DispatchQueue.main.async within the CVDisplayLink output callback.