[net11.0] Move feature switch RHCO items to static evaluation to fix IL3050 on Android NativeAOT by sbomer · Pull Request #35134 · dotnet/maui

sbomer · 2026-04-24T18:58:48Z

Note

This PR was created with assistance from AI.

Summary

Move RuntimeHostConfigurationOption items and their property defaults out of the _MauiPrepareForILLink target into static PropertyGroup/ItemGroup blocks evaluated at import time. This requires no runtime changes.

Problem

dotnet/runtime#124801 moved the RuntimeHostConfigurationOption → _TrimmerFeatureSettings conversion from PrepareForILLink into an earlier internal target (_PrepareTrimConfiguration). MAUI's _MauiPrepareForILLink hooks BeforeTargets="PrepareForILLink", which fires after the snapshot. ILC never receives --feature flags for MAUI's switches on Android NativeAOT, causing spurious IL3050 warnings for HybridWebViewHandler.

Fix

The property conditions (PublishAot, TrimMode, Optimize) are all static project properties available at evaluation time — there's no reason for these to be set inside a target. Moving them to static blocks makes them visible before any targets run, so _PrepareTrimConfiguration picks them up regardless of target ordering.

A sentinel property (_EnableMauiAspireUserOverride) captures the user-specified _EnableMauiAspire value before the default is set, so the MA002 warning correctly detects external overrides without false positives from MAUI's own default.

The Warning task (MA002 Aspire validation) remains in _MauiPrepareForILLink since MSBuild tasks require a target context.

This approach requires no runtime changes.

Verified

Tested locally with an Android NativeAOT MAUI app:

Before: --feature:Microsoft.Maui.RuntimeFeature.IsHybridWebViewSupported=false missing from ILC rsp → IL3050
After: --feature flag present → IL3050 suppressed by FeatureGuard

Fixes dotnet/runtime#127017

cc @sbomer @simonrozsival @MichalStrehovsky

Move PropertyGroup defaults and RuntimeHostConfigurationOption items out of _MauiPrepareForILLink (a target) into static PropertyGroup/ItemGroup blocks that are evaluated at import time. This ensures RHCO items are visible before any MSBuild targets run, so _PrepareTrimConfiguration can snapshot them into _TrimmerFeatureSettings for both ILLink and ILC. Previously these were added in _MauiPrepareForILLink (BeforeTargets= "PrepareForILLink"), but runtime PR dotnet/runtime#124801 moved the RHCO → _TrimmerFeatureSettings conversion to an earlier target (_PrepareTrimConfiguration), causing MAUI's feature switches to be missed by ILC on Android NativeAOT. The property conditions (PublishAot/TrimMode) are static project properties available at evaluation time, so there is no need for these to run inside a target. The Warning task for MA002 remains in _MauiPrepareForILLink since MSBuild tasks require a target context. Fixes dotnet/runtime#127017 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Assisted-by: Claude:claude-opus-4.6-1m

Capture the user-specified _EnableMauiAspire value into a sentinel property (_EnableMauiAspireUserOverride) before setting the default. The MA002 warning now checks the sentinel instead of _EnableMauiAspire itself, so it only fires when the user explicitly set the property. Previously the Warning ran inside a target before _EnableMauiAspire was set, so checking '!= empty' correctly detected user overrides. Now that _EnableMauiAspire is set statically, MAUI always populates it, so the sentinel is needed to distinguish user vs MAUI values. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Assisted-by: Claude:claude-opus-4.6-1m

github-actions · 2026-04-24T18:58:58Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://github.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 35134

Or

Run remotely in PowerShell:

iex "& { $(irm https://github.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 35134"

Copilot

Pull request overview

Moves MAUI feature switch defaults and RuntimeHostConfigurationOption items to MSBuild evaluation-time so the runtime’s earlier trim configuration snapshot (_PrepareTrimConfiguration) can pick them up, fixing missing --feature flags in Android NativeAOT scenarios.

Changes:

Relocates feature-switch property defaults and RuntimeHostConfigurationOption items out of _MauiPrepareForILLink into static PropertyGroup/ItemGroup blocks.
Adds _EnableMauiAspireUserOverride to preserve the ability to warn only on user overrides after defaults moved to evaluation time.
Keeps MA002 warning emission in _MauiPrepareForILLink (target context).

Copilot · 2026-04-24T19:02:20Z

+    evaluation time, before _PrepareTrimConfiguration snapshots RHCO items into
+    _TrimmerFeatureSettings. Previously these lived inside _MauiPrepareForILLink
+    (BeforeTargets="PrepareForILLink"), but that fires after _PrepareTrimConfiguration
+    runs, so ILC never received - -feature flags for MAUI switches on Android NativeAOT.


The comment says "ILC never received - -feature flags". This looks like a typo; it should be "--feature" (double hyphen) to match the actual ILC option name.

Suggested change

runs, so ILC never received - -feature flags for MAUI switches on Android NativeAOT.

runs, so ILC never received --feature flags for MAUI switches on Android NativeAOT.

Copilot · 2026-04-24T19:02:21Z

+    <!-- Capture user-specified value before setting the default, so the MA002
+         warning can detect external overrides. -->
+    <_EnableMauiAspireUserOverride>$(_EnableMauiAspire)</_EnableMauiAspireUserOverride>
+    <!-- Set _EnableMauiAspire based on whether optimizations are enabled when not already set -->
+    <_EnableMauiAspire Condition="'$(_EnableMauiAspire)' == '' and '$(Optimize)' != 'true'">true</_EnableMauiAspire>
+    <_EnableMauiAspire Condition="'$(_EnableMauiAspire)' == ''">false</_EnableMauiAspire>


_EnableMauiAspireUserOverride is only captured when PublishAot is true or TrimMode is full. If a user sets _EnableMauiAspire manually in an optimized build without those settings, MA002 will no longer trigger (the warning condition now checks only _EnableMauiAspireUserOverride). Consider capturing _EnableMauiAspireUserOverride unconditionally (e.g., in a separate PropertyGroup before any defaults are applied, and guarded so it doesn't overwrite) so the warning continues to detect external overrides in all optimized builds.

MauiCssEnabled's condition uses '@(MauiCss->Count())' which is an item list reference not allowed in static PropertyGroup conditions (MSB4099). Move it and its RHCO item back into _MauiPrepareForILLink. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Assisted-by: Claude:claude-opus-4.6-1m

simonrozsival · 2026-04-27T08:07:31Z

      <RuntimeHostConfigurationOption Include="Microsoft.Maui.RuntimeFeature.IsCssEnabled"
                                      Condition="'$(MauiCssEnabled)' != ''"
                                      Value="$(MauiCssEnabled)"
                                      Trim="true" />


Why isn't this one moved too? Is it because MauiCssEnabled is evaluated later based on the presence of any @(MauiCss) items?

I overlooked this comment.

Won't this cause the same issues which were caused by placing the other RHCO inside of the target? Could it happen that this feature switch is set too late due to some unexpected targets ordering?

Replace the @(MauiCss->Count()) item list check with a property-based condition on EnableDefaultCssItems. MSBuild does not allow @() item references in static PropertyGroup conditions (MSB4099). When EnableDefaultCssItems is not 'true', no CSS glob runs, so MauiCssEnabled defaults to false. When it is 'true', MauiCssEnabled stays unset (CSS enabled by default) regardless of whether CSS files exist on disk — the CSS code paths are present but never invoked if no stylesheets are loaded, so there is no runtime behavior change. This empties _MauiPrepareForILLink of all property/item logic, leaving only the MA002 Warning task which requires a target context. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Assisted-by: Claude:claude-opus-4.6-1m

sbomer · 2026-04-28T17:38:59Z

Closing this - #35094 works around the break, and MAUI folks need to decide how to address #35163.

sbomer and others added 2 commits April 24, 2026 11:50

Copilot AI review requested due to automatic review settings April 24, 2026 18:58

Copilot started reviewing on behalf of sbomer April 24, 2026 18:59 View session

Copilot AI reviewed Apr 24, 2026

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github-actions Bot mentioned this pull request Apr 25, 2026

[repo-status] 🌟 Daily Repo Status - April 25, 2026 #35135

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simonrozsival reviewed Apr 27, 2026

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sbomer mentioned this pull request Apr 27, 2026

Feature switch RuntimeHostConfigurationOption items should be set during static evaluation #35163

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sbomer closed this Apr 28, 2026

PureWeen mentioned this pull request Apr 30, 2026

[iOS] Suppress IL2026 trim warnings on HybridWebViewHandler nested classes #35262

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[net11.0] Move feature switch RHCO items to static evaluation to fix IL3050 on Android NativeAOT#35134

[net11.0] Move feature switch RHCO items to static evaluation to fix IL3050 on Android NativeAOT#35134
sbomer wants to merge 4 commits intonet11.0from
dev/sbomer/maui-il3050-static-net11

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	runs, so ILC never received - -feature flags for MAUI switches on Android NativeAOT.
	runs, so ILC never received --feature flags for MAUI switches on Android NativeAOT.

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sbomer commented Apr 24, 2026

Summary

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Fix

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