Migrate JitOptimizationSensitive and GCStressIncompatible to SkipOnCoreClr attributes by Copilot · Pull Request #126108 · dotnet/runtime

Copilot · Mar 25, 2026

Replaces eligible MSBuild <JitOptimizationSensitive> and <GCStressIncompatible> properties with [SkipOnCoreClr(...)] applied directly to test entry points, moving skip logic from build-time property injection into the XUnit test runner where the test can safely run without process isolation.

Description

Why

MSBuild properties like <GCStressIncompatible> and <JitOptimizationSensitive> require <RequiresProcessIsolation>true</RequiresProcessIsolation> to take effect — process isolation is expensive. Moving eligible skips to XUnit attributes allows tests to be skipped in-process without spawning a new process per test. Tests that still require process isolation for other reasons retain <RequiresProcessIsolation>true</RequiresProcessIsolation>.

Changes

JitOptimizationSensitive — ilproj tests (4 .il files, 4 .ilproj files)

Added SkipOnCoreClrAttribute with AnyJitOptimizationStress (0x11E) to each IL entry point
Added .assembly extern Microsoft.DotNet.XUnitExtensions where missing
Removed <JitOptimizationSensitive> and sole-cause <RequiresProcessIsolation> from project files
Added <ProjectReference Include="$(TestLibraryProjectPath)" /> to project files that were missing it

GCStressIncompatible — all project types (~310 files total)

C# (150 .cs + 150 .csproj):

Added [SkipOnCoreClr("This test is not compatible with GC stress.", RuntimeTestModes.AnyGCStress)] before each [Fact]/[Theory]/[ConditionalFact]/[ConditionalTheory]
Removed <GCStressIncompatible> and sole-cause <RequiresProcessIsolation> from project files
Added <ProjectReference Include="$(TestLibraryProjectPath)" /> to 65 csproj files that were missing it
Removed dangling <GCStressIncompatible> from project files where the compiled source already had a corresponding [SkipOnCoreClr(..., RuntimeTestModes.AnyGCStress)] attribute

IL (6 .ilproj, 3 .il):

3 GenericContext tests: IL was pre-migrated; removed MSBuild properties from project files
3 JIT regression tests: Added SkipOnCoreClrAttribute (0xC0 = AnyGCStress) to IL entry points; updated project files
Added <ProjectReference Include="$(TestLibraryProjectPath)" /> to 6 ilproj files that were missing it

F#:

Runtime_72845 was left on the standalone [<EntryPoint>]/exit-code pattern with <GCStressIncompatible>true</GCStressIncompatible> and <RequiresProcessIsolation>true</RequiresProcessIsolation> retained, because the attempted XUnit conversion did not compile in targeted test builds

HeapVerifyIncompatible — migrated tests

Added <ProjectReference Include="$(TestLibraryProjectPath)" /> to project files that were missing it
For tests where <HeapVerifyIncompatible> was conditional on architecture, replaced the unconditional [SkipOnCoreClr(..., RuntimeTestModes.HeapVerify)] with [ConditionalFact] backed by a static bool property that combines the architecture check with TestLibrary.CoreClrConfigurationDetection.IsHeapVerify, preserving the original per-architecture skip semantics

Comment cleanup

Audited edited project files where <GCStressIncompatible> was removed and updated or removed stale RequiresProcessIsolation comments
Audited orphaned project comments that provided GC stress skip context, removed the orphaned comments, and moved important issue/context details into the corresponding [SkipOnCoreClr(...)] attribute messages
Kept remaining RequiresProcessIsolation rationale comments positioned above the <RequiresProcessIsolation> property they describe

Infrastructure and documentation

Doubled the browser-wasm (CoreCLR) runtime test work item timeout in helixpublishwitharcade.proj (123 → 246 minutes) to accommodate the larger merged test collections
Updated requiresprocessisolation.md to document two additional triggers for <RequiresProcessIsolation>: <IsLongRunningGCTest> and <CLRTestExecutionArguments>

CI failure fixes and process-isolation audit

Restored <RequiresProcessIsolation>true</RequiresProcessIsolation> to tests that still require isolation for GC measurement accuracy, long-running GC pre-commands, custom CLR test execution arguments, GC.WaitForPendingFinalizers, unsupported target handling, unloadability, NativeAOT incompatibility, output-copying project references, or Process.Start
Added targeted [ActiveIssue] suppressions for CI failures on browser-wasm CoreCLR and Mono interpreter browser-wasm where appropriate
Resolved merge conflict in GetTotalAllocatedBytes.cs while preserving GC stress and HeapVerify skip behavior

Not migrated (MSBuild property retained)

Tests with ReferenceXUnitWrapperGenerator=false — no XUnit runner
Profiler tests — custom host runner with no XUnit
HW intrinsics wrapper projects — architecture-conditional property, no owned source
OutputType=Library projects — no entry point
Tests using top-level statements with no [Fact] method
Runtime_72845.fsproj — F# XUnit conversion did not compile in targeted test builds, so this test retains <GCStressIncompatible>true</GCStressIncompatible> and standalone process isolation
ReadyToRun tests with crossgen2 shell pre-commands (multifolder, determinism/crossgen2determinism) — [SkipOnCoreClr] only skips the XUnit test body, not pre-commands that run before the test executable
Tests that still match requiresprocessisolation.md rules retain <RequiresProcessIsolation>, including projects with CLRTestExecutionArguments, IsLongRunningGCTest, GC.WaitForPendingFinalizers, CLRTestTargetUnsupported, UnloadabilityIncompatible, NativeAotIncompatible, ProjectReference/content copying requirements, or Process.Start

…odes.HeapVerify) Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/b9ff7f11-db85-474b-bed1-1e4bd364f234

…ource files Replace MSBuild property JitOptimizationSensitive with [SkipOnCoreClr("This test is sensitive to JIT optimizations.", RuntimeTestModes.AnyJitOptimizationStress)] attribute directly on [Fact]/[Theory] methods across 48 test source files. Corresponding .csproj files have the <JitOptimizationSensitive> property removed. RequiresProcessIsolation is also removed from project files where JitOptimizationSensitive was the sole reason for it. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…e migration Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/291e5882-a072-4964-8394-d20db497e472

…IL source files Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e0266c53-b95c-4538-80c9-b7d881f45840

… ilproj, fsproj Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/66a86949-b520-4439-8d71-659f2b4391fc

…projects - Remove GCStressIncompatible from 7 OutputType=Library projects where the property is a no-op. - Remove redundant conditional GCStressIncompatible from 10 X86 HWIntrinsics projects (both arm64+osx and arm conditions already covered by CLRTestTargetUnsupported). - Remove redundant arm-only GCStressIncompatible from 2 Arm HWIntrinsics projects (arm condition already covered by CLRTestTargetUnsupported). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Add runtime HeapVerify check to ServerModel test using CoreClrConfigurationDetection.IsHeapVerify (the last project using it). - Remove HeapVerify skip logic from Batch and Bash execution script targets. - Remove auto-setting of HeapVerifyIncompatible for disasm-check tests in CLRTest.Jit.targets. - Remove all documentation references to HeapVerifyIncompatible. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

dotnet-policy-service · Mar 25, 2026

Tagging subscribers to this area: @agocke, @dotnet/gc
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MichalStrehovsky · Mar 25, 2026

Before we make more changes to the test tree, it would be nice to make the test tree buildable again. https://github.com/dotnet/runtime/runs/68503855882

I assume this is from #125460, I've seen similar failures when I worked on the Loader tree. It would be nice to re-validate we're still running the same number of tests after #125460, the validation at #125460 (comment) must have missed this.

jkoritzinsky · Mar 26, 2026

I must have fat fingered the build command and missed the pri1 tests somehow. I'll fix that up before coming back to this.

jkoritzinsky · Mar 31, 2026

/azp run runtime-coreclr outerloop

azure-pipelines · Mar 31, 2026

Azure Pipelines successfully started running 1 pipeline(s).

jkoritzinsky · Apr 2, 2026

@copilot some of the projects you've edited still mention that they have RequiresProcessIsolation due to GCStressIncompatible. Please audit the projects you've edited to make sure that the reasons for a project being marked RPI are accurate.

… comments Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c882c5b1-c293-4d09-8e31-17947a0bdd1e Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Copilot · Apr 2, 2026

@copilot some of the projects you've edited still mention that they have RequiresProcessIsolation due to GCStressIncompatible. Please audit the projects you've edited to make sure that the reasons for...

Done in 48bc184. Audited all 78 project files where GCStressIncompatible was removed but the  comment on RequiresProcessIsolation still referenced it. Updated each comment to reflect only the remaining reasons (e.g. UnloadabilityIncompatible, GC.WaitForPendingFinalizers, CMakeProjectReference, etc.). When GCStressIncompatible was the sole reason, the entire comment line was removed.

Copilot

Copilot wasn't able to review this pull request because it exceeds the maximum number of files (300). Try reducing the number of changed files and requesting a review from Copilot again.

github-actions

Holistic Review

Motivation: Justified, unchanged. <GCStressIncompatible>, <JitOptimizationSensitive>, and <HeapVerifyIncompatible> only take effect when <RequiresProcessIsolation>true</RequiresProcessIsolation> forces an expensive per-test process. Moving eligible skips to XUnit [SkipOnCoreClr(...)]/[ConditionalFact] lets the merged in-process runner skip them without spawning a process, which is a real CI cost win.

Approach: Sound and idiomatic, unchanged. Managed entry points use [SkipOnCoreClr(msg, RuntimeTestModes.AnyGCStress|AnyJitOptimizationStress)] and IL entry points use equivalent .custom ... SkipOnCoreClrAttribute records with the correct Microsoft.DotNet.XUnitExtensions extern and public key token, mirroring the established src/tests pattern. Architecture-conditional HeapVerifyIncompatible is preserved via [ConditionalFact] gated on Utilities.IsArm/IsX86/... and CoreClrConfigurationDetection.IsHeapVerify. <RequiresProcessIsolation> is retained where genuinely required.

Summary: This is an incremental re-review. The 23 PR commits are byte-for-byte identical to the previously reviewed head (range-diff shows all 23 patches equal); the head SHA differs only because the PR was rebased onto a newer base. The sole semantic delta in the cumulative patch is in src/tests/Common/helixpublishwitharcade.proj: the doubled browser-wasm collection timeout (_TimeoutPerTestCollectionInMinutes = 246) was re-expressed during the rebase to match the reworked surrounding TargetsMobile condition, and now also applies to TargetsWasiOnCoreCLR. This is a benign, consistency-improving adaptation to upstream changes, not a behavioral regression, and it does not alter the motivation, approach, or risk of the PR. No new actionable findings. Overall verdict remains LGTM.

Assessment History

review 4730527139 reviewed commit 6d716aed9b8626ea8447a09af4dabd2017b787c1 with an LGTM verdict. Current verdict is also LGTM. Assessment unchanged: verdict, motivation, approach, and risk are all the same. The only intervening change is a rebase that preserved every PR patch and adjusted the browser-wasm timeout condition to also cover WASI, which does not affect the assessment.

Detailed Findings

None. The incremental change (WASI-inclusive browser-wasm timeout condition in helixpublishwitharcade.proj) is correct and consistent with the adjacent TargetsMobile logic.

Note

This review was generated by this repository's Holistic Review agentic workflow to complement the built-in Copilot review.

Generated by Holistic Review · 59.8 AIC · ⌖ 10.6 AIC · ⊞ 10K

jkoritzinsky · Jul 20, 2026

/azp run runtime-coreclr outerloop

azure-pipelines · Jul 20, 2026

Azure Pipelines: Successfully started running 1 pipeline(s).

jkoritzinsky · Jul 21, 2026

@copilot please inspect the CI failures and mark the tests that failed due to multithreading as conditional on multithreading support.

Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Copilot

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Copilot · Jul 22, 2026

@copilot please inspect the CI failures and mark the tests that failed due to multithreading as conditional on multithreading support.

Fixed in 711de57. I inspected the browser-wasm CoreCLR CI failures and marked the tests that depend on managed Thread.Start support with [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsMultithreadingSupported))]: 437044, 576463, MultipleException, RecursiveException, and Test12224.

jkoritzinsky · Jul 22, 2026

/azp run runtime-coreclr outerloop

azure-pipelines · Jul 22, 2026

Azure Pipelines: Successfully started running 1 pipeline(s).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: dfcc4829-304a-4277-ac35-91ba6510eb70

Copilot

Copilot wasn't able to review this pull request because it exceeds the maximum number of files (300). Try reducing the number of changed files and requesting a review from Copilot again.

jkoritzinsky · Jul 25, 2026

/azp run runtime-coreclr outerloop

azure-pipelines · Jul 25, 2026

Azure Pipelines: Successfully started running 1 pipeline(s).

jkoritzinsky · Jul 27, 2026

/ba-g no unknown failures but BA still red

Copilot AI and others added 7 commits March 24, 2026 21:57

Migrate HeapVerifyIncompatible to SkipOnCoreClrAttribute(RuntimeTestM…

6fe72fe

…odes.HeapVerify) Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/b9ff7f11-db85-474b-bed1-1e4bd364f234

Fix runtimeeventsource and allocationsampling JitOptimizationSensitiv…

4643fcd

…e migration Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/291e5882-a072-4964-8394-d20db497e472

Migrate ilproj JitOptimizationSensitive to SkipOnCoreClrAttribute in …

5b2d53a

…IL source files Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/e0266c53-b95c-4538-80c9-b7d881f45840

Migrate GCStressIncompatible to SkipOnCoreClrAttribute across csproj,…

5988bee

… ilproj, fsproj Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com> Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/66a86949-b520-4439-8d71-659f2b4391fc

Copilot AI assigned Copilot and jkoritzinsky Mar 25, 2026

github-project-automation Bot added this to AppModel Mar 25, 2026

Copilot created this pull request from a session on behalf of jkoritzinsky March 25, 2026 17:27 View session

github-actions Bot added the area-GC-coreclr label Mar 25, 2026

jkoritzinsky requested review from MichalStrehovsky and Copilot March 25, 2026 17:55

Copilot AI reviewed Mar 25, 2026

MichalStrehovsky mentioned this pull request Mar 26, 2026

Fix COMDelegate::BindToMethod with static virtuals #125875

Merged

Add missing test library references

d4e4e88

Copilot started work on behalf of jkoritzinsky April 2, 2026 18:46 View session

Fix stale GCStressIncompatible references in RequiresProcessIsolation…

48bc184

… comments Agent-Logs-Url: https://github.com/dotnet/runtime/sessions/c882c5b1-c293-4d09-8e31-17947a0bdd1e Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Copilot finished work on behalf of jkoritzinsky April 2, 2026 18:52

Copilot AI review requested due to automatic review settings July 20, 2026 18:21

Copilot AI reviewed Jul 20, 2026

github-actions Bot reviewed Jul 20, 2026

View reviewed changes

Copilot started work on behalf of jkoritzinsky July 21, 2026 23:58 View session

Skip thread-dependent tests without multithreading

711de57

Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Copilot AI review requested due to automatic review settings July 22, 2026 00:26

Copilot AI reviewed Jul 22, 2026

Copilot finished work on behalf of jkoritzinsky July 22, 2026 00:27

MichalStrehovsky reviewed Jul 22, 2026

View reviewed changes

Address test isolation migration feedback

0e985e0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: dfcc4829-304a-4277-ac35-91ba6510eb70

Copilot AI review requested due to automatic review settings July 23, 2026 19:39

Copilot AI reviewed Jul 23, 2026

jkoritzinsky requested a review from MichalStrehovsky July 24, 2026 17:41

build-analysis Bot mentioned this pull request Jul 25, 2026

Error while retrieving client Settings for PipelineArtifact. HttpRequestException: nodename nor servname provided, or not known (vsblobprodcus3.vsblob.visualstudio.com:443) #96798

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MichalStrehovsky approved these changes Jul 27, 2026

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jkoritzinsky enabled auto-merge (squash) July 27, 2026 17:12

jkoritzinsky merged commit c35b7ab into main Jul 27, 2026
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[main] Source code updates from dotnet/runtime dotnet/dotnet#8003

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Changes

Not migrated (MSBuild property retained)

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Holistic Review

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