| commit | 23fc43d5e61f5d45bf30fbdf6faed1623597c486 | [log] [tgz] |
|---|---|---|
| author | Chris Bracken <chris@bracken.jp> | Tue Dec 10 11:06:13 2024 -0800 |
| committer | GitHub <noreply@github.com> | Tue Dec 10 19:06:13 2024 +0000 |
| tree | 3f4c3c04e652030671ede8d28d892e58810b534b | |
| parent | 3f796274ab2a31e2147a78d9f81a6f24c9b97f98 [diff] |
iOS: Add null checks on shell dereference (#57099) `FlutterEngine` at the `_shell` unique_ptr ivar it owns have different lifetimes. `_shell` is initialised transitively from `runWithEntrypoint`, and reset in `[FlutterEngine destroyContext]`, which is called transitively from `[FlutterviewController dealloc]` via `[FlutterEngine notifyViewControllerDeallocated]`. As such, all uses of `_shell` should be checked either via an assertion, in cases we know the shell should be non-null, or via a runtime null check in cases where it's expected that it may be null. Specifically, this guards against a crash that can occur if we get a CoreAnimation transaction commit callback for an inflight frame just as we're shutting down the app (or removing the FlutterView in an add-to-app scenario). Example stack trace: ``` 0 Flutter 0x11b28 -[FlutterEngine platformView] + 53 (weak_ptr.h:53) 1 Flutter 0x11994 -[FlutterEngine updateViewportMetrics:] + 186 (ref_ptr.h:186) 2 Flutter 0x1f854 -[FlutterViewController updateViewportMetricsIfNeeded] + 427 (vector:427) 3 Flutter 0x1f9b8 -[FlutterViewController viewDidLayoutSubviews] + 1411 (FlutterViewController.mm:1411) 4 UIKitCore 0x8c864 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2376 5 QuartzCore 0x1fa0c CA::Layer::layout_if_needed(CA::Transaction*) + 516 6 QuartzCore 0x1ae84c CA::Context::commit_transaction(CA::Transaction*, double, double*) + 516 7 QuartzCore 0x2888 CA::Transaction::commit() + 648 ``` Issue: https://github.com/flutter/flutter/issues/98735 Issue: https://github.com/flutter/flutter/issues/159639 [C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
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