[ci-fix] Fix IL2009 AOT trim warning from CustomPressGestureRecognizer ObjC registration-name collision

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Note

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It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Target branch: net11.0

🟡 Help wanted — candidate fix, not yet runner-validated. This draft was produced by the automated CI-failure fixer. The change is a well-reasoned candidate, but it could not be validated on the workflow runner (Linux, no Apple workloads → the iOS/MacCatalyst full-trim AOT template test cannot be built or published here). A maintainer with an iOS/MacCatalyst trim-capable environment should validate before merge.

Problem

The maui-pr AOT/trimming template test (full-trim publish of a net11.0-maccatalyst / net11.0-ios template app) fails on net11.0 because the trimmer writes an unexpected linker-warning file. The warning is:

IL2009: Could not find method 'Activated(T)' on type 'UIKit.UIGestureRecognizer.Callback`1'

Verified to still reproduce against the latest completed maui-pr (definition 302) net11.0 build (build #1477477 — present across many RIDs in the failed-leg logs). The warning is emitted into apply-preserve-attribute.xml, and the AOT-warnings test infra (BuildWarningsUtilities.AssertWarnings, which carries an empty iOS/MacCatalyst native-AOT warning baseline) treats the presence of any warning file as "Unexpected warning files detected!", failing the test.

Root cause

CustomPressGestureRecognizer.Callback registers its Objective-C class name as __UIGestureRecognizer:

[Register("__UIGestureRecognizer")]
class Callback : Token

That is the same Objective-C class name the Microsoft.iOS SDK uses for its own internal UIKit.UIGestureRecognizer.Callback token type. Because two managed types claim the identical native registration name, the [Preserve(Conditional = true)] attribute on MAUI's Activated(UIGestureRecognizer) produces a preserve descriptor whose declaring type — when the linker resolves it by registered name — binds to the SDK's generic UIGestureRecognizer.Callback\1. That token type has no Activated(T)member in the current SDK, so the descriptor is unresolvable →IL2009`.

Fix

Give MAUI's nested Callback a unique registration name. The preserve descriptor then resolves to MAUI's own type, whose Activated(UIGestureRecognizer) exists, so no warning is generated:

[Register("Microsoft_Maui_Controls_Platform_iOS_CustomPressGestureRecognizer_Callback")]
class Callback : Token

This also removes a latent duplicate Objective-C class registration (two managed types registering __UIGestureRecognizer), which is incorrect on its own. The callback is dispatched through the target: selector ([Export("target:")]), not by class name, and MAUI always instantiates its own Callback, so the rename does not change runtime behavior. The change is a single line in src/Controls/src/Core/Platform/iOS/CustomPressGestureRecognizer.cs and touches no test or assertion.

Why help-wanted / how to validate

The fixer runs on Linux without Apple workloads and cannot build or publish the maccatalyst/ios full-trim template, so it cannot confirm the warning is gone. To validate:

• Run the AOT template integration test that publishes a fully-trimmed net11.0-maccatalyst (and net11.0-ios) app and asserts no unexpected warning files (Microsoft.Maui.IntegrationTests, AOT category), or
• dotnet publish -f net11.0-maccatalyst -c Release a minimal MAUI app with full trimming enabled and confirm no IL2009 referencing UIGestureRecognizer.Callback appears.

Alternative considered

Removing the now-arguably-redundant [Preserve(Conditional = true)] on Activated (the [Export]ed member of a registrar-rooted NSObject is already a static-registrar root under full trimming) would also stop the descriptor from being generated. The rename was preferred because it fixes the underlying native-name collision rather than only suppressing its symptom, and it keeps the explicit preservation intent.

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Refs: #36081
Attempt: 1/5
Flake-class: n/a (hard, deterministic failure — reproduces every recent net11.0 build)

Generated by CI Failure Fixer (net11.0) · 2.7K AIC · ⌖ 71.1 AIC · ⊞ 66.9K · ◷

[PureWeen]

Closing as superseded. The only change in this PR — renaming the ObjC registration name on CustomPressGestureRecognizer from __UIGestureRecognizer to a unique callback name — already landed in main via #36125 ("Fix AOT trim warnings on net11.0", merged 2026-06-26), which touches the same file and additionally fixes BuildWarningsUtilities.cs and the [Preserve] attribute. This bot PR is now redundant. Tracking issue #36081 should be verified against #36125.

Closed by the CI-fix triage sweep.