[pavelsavara]

Summary

Fix argument corruption after exception filters in Mono AOT code.

interp_run_clause_with_il_state used the first argument slot as the filter-result buffer. MINT_ENDFILTER wrote the filter result there, and argument writeback copied it into the suspended AOT frame before the catch ran. This made an integer argument become 1 and corrupted string references.

Give filter evaluation a separate result slot, following the normal interpreter filter path. Catch/finally return storage and legitimate argument/local writeback remain unchanged.

Add the eight reported scenarios to the existing System.Runtime.Tests exception suite, plus two cases ensuring argument mutations survive both accepted and rejected filters.

Testing

Mono/browser-wasm Debug runtime and libraries; Release test app; Chrome with a matching ChromeDriver. $root is the checkout path. The local runs used the cached Emscripten SDK via EMSDK_PATH and cached Chrome via CHROME_PATH_FOR_TESTS.

Runtime/libraries/packs build: passed, 0 warnings and 0 errors.

.\build.cmd -bl -os browser -subset mono+libs+packs -c Debug /p:RuntimeFlavor=Mono /p:EnableHotReloadInRuntimeConfigDevFile=false

Chrome AOT exception suite: passed, 18/18 tests. Before the fix, the same suite ran 18 tests with 7 failures: the five original failing scenarios and both argument-mutation cases.

.\dotnet.cmd build -bl /p:TargetOS=browser /p:TargetArchitecture=wasm /p:RuntimeFlavor=Mono /p:Configuration=Release /p:RuntimeConfiguration=Debug /p:RuntimeConfig=Debug /p:LibrariesConfiguration=Debug /p:TasksConfiguration=Debug "/p:WasmTestRunnerDir=$root\artifacts\bin\WasmTestRunner\Debug\net12.0-browser\" /t:Test /p:RunAOTCompilation=true /p:Scenario=WasmTestOnChrome /p:InstallChromeForTests=false /p:EnableHotReloadInRuntimeConfigDevFile=false /p:XUnitClassName=System.Tests.ExceptionTests .\src\libraries\System.Runtime\tests\System.Runtime.Tests\System.Runtime.Tests.csproj

Chrome interpreter exception suite: passed, 20/20 tests. Cleaned this test project's browser-wasm bin/obj directories before switching AOT off to avoid reusing IL-stripped staging. Two existing target-site tests have Mono-AOT exclusions and therefore run only in the interpreter configuration.

.\dotnet.cmd build -bl /p:TargetOS=browser /p:TargetArchitecture=wasm /p:RuntimeFlavor=Mono /p:Configuration=Release /p:RuntimeConfiguration=Debug /p:RuntimeConfig=Debug /p:LibrariesConfiguration=Debug /p:TasksConfiguration=Debug "/p:WasmTestRunnerDir=$root\artifacts\bin\WasmTestRunner\Debug\net12.0-browser\" /t:Test /p:RunAOTCompilation=false /p:Scenario=WasmTestOnChrome /p:InstallChromeForTests=false /p:EnableHotReloadInRuntimeConfigDevFile=false /p:XUnitClassName=System.Tests.ExceptionTests .\src\libraries\System.Runtime\tests\System.Runtime.Tests\System.Runtime.Tests.csproj

The original eight-case probe also passes all cases under both AOT and the interpreter. Other target platforms were not tested locally.

Resolves #136780

Note

This change and PR description were prepared with GitHub Copilot.

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[pavelsavara]

/azp run runtime-extra-platforms

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[pavelsavara]

/ba-g unrelated CI failures

[pavelsavara]

/backport to release/11.0

[github-actions]

Started backporting to release/11.0 (link to workflow run)

[github-actions]

@pavelsavara backporting to release/11.0 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git cherry-pick 76e0443e3d4e50f09b831b95c8d32046176c1990

Auto-merging src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ExceptionTests.cs
CONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ExceptionTests.cs
error: could not apply 76e0443e3d4... [mono] Preserve arguments across AOT exception filters (#136852)
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
hint: Disable this message with "git config set advice.mergeConflict false"


$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: [mono] Preserve arguments across AOT exception filters
Using index info to reconstruct a base tree...
M	src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ExceptionTests.cs
Falling back to patching base and 3-way merge...
Auto-merging src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ExceptionTests.cs
CONFLICT (content): Merge conflict in src/libraries/System.Runtime/tests/System.Runtime.Tests/System/ExceptionTests.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 [mono] Preserve arguments across AOT exception filters
Error: The process '/usr/bin/git' failed with exit code 128

Link to workflow output