[iOS] Fix MauiCALayer and StaticCAShapeLayer crash on finalizer thread

[pshoey]

Description of Change

MauiCALayer and StaticCAShapeLayer crash with EXC_BAD_ACCESS when disposed on the finalizer thread in Release/AOT builds. The crash occurs because Dispose() unconditionally calls _autosizeToSuperLayerBehavior.Detach(), which invokes Objective-C methods on native CALayer objects that may have already been deallocated by UIKit.

The fix wraps the Detach() call in if (disposing) to follow the standard .NET dispose pattern - only call into external/native objects during explicit disposal, not during finalization.

Issues Fixed

Fixes #33800

Changes

• src/Core/src/Platform/iOS/MauiCALayer.cs - Wrap Detach() call in if (disposing)
• src/Core/src/Platform/iOS/StaticCAShapeLayer.cs - Wrap Detach() call in if (disposing)
• src/Core/src/Platform/iOS/StaticCALayer.cs - Wrap Detach() call in if (disposing)
• src/Core/src/Platform/iOS/StaticCAGradientLayer.cs - Wrap Detach() call in if (disposing)

Testing

• Built MAUI from source with this fix
• • Tested in a production iOS app (Release/AOT via TestFlight)
• • Confirmed crashes no longer occur with the patched Microsoft.Maui.Core

[Copilot]

Pull request overview

This PR prevents EXC_BAD_ACCESS crashes on the finalizer thread for iOS MauiCALayer and StaticCAShapeLayer by making their dispose logic finalizer-safe, aligning with the standard .NET dispose pattern for objects that wrap UIKit-managed native layers.

Changes:

• Update MauiCALayer.Dispose(bool disposing) to only call _autosizeToSuperLayerBehavior.Detach() when disposing == true, avoiding native calls during finalization.
• Update StaticCAShapeLayer.Dispose(bool disposing) similarly to guard the Detach() call behind if (disposing) while keeping RemoveFromSuperLayer behavior unchanged.

For a follow-up (not blocking this PR), consider applying the same if (disposing) guard in Dispose for other IAutoSizableCALayer implementations using MauiCALayerAutosizeToSuperLayerBehavior (e.g., StaticCALayer, StaticCAGradientLayer) to ensure consistent finalizer safety across all such layers.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Core/src/Platform/iOS/MauiCALayer.cs	Makes Dispose(bool) finalizer-safe by only detaching the autosize behavior when explicitly disposing, preventing Obj-C calls on potentially deallocated CALayer instances.
src/Core/src/Platform/iOS/StaticCAShapeLayer.cs	Applies the same guarded-detach pattern in Dispose(bool) for StaticCAShapeLayer to avoid finalizer-thread crashes while preserving detach behavior in RemoveFromSuperLayer.

[albyrock87]

Thanks for your first contribution!
The fix looks good though there should be other classes to be fixed: look for who implements IAutoSizableCALayer.

[rmarinho]

📋 PR Finalization Review

Title: ✅ Good

Current: [iOS] Fix MauiCALayer and StaticCAShapeLayer crash on finalizer thread

Description: ✅ Good

Description needs updates. See details below.
Missing Elements:

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• ❌ Missing required NOTE block at top
• ⚠️ Minor formatting: Double dashes in Changes/Testing sections

Recommendation: Add NOTE block at top, clean up formatting. Keep all existing content - it's well-written and accurate.

---

✨ Suggested PR Description

<!-- Please let the below note in for people that find this PR -->
> [!NOTE]
> Are you waiting for the changes in this PR to be merged?
> It would be very helpful if you could [test the resulting artifacts](https://github.com/dotnet/maui/wiki/Testing-PR-Builds) from this PR and let us know in a comment if this change resolves your issue. Thank you!
</details>

[pshoey]

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[PureWeen]

/azp run maui-pr-uitests, maui-pr-devicetests

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[PureWeen]

/backport to release/10.0.1xx-sr3

[github-actions]

Started backporting to release/10.0.1xx-sr3 (link to workflow run)