Restore isolation for GC Collect tests by kkokosa · Pull Request #132076 · dotnet/runtime

kkokosa · 2026-08-10T13:19:33Z

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

kkokosa · 2026-08-10T13:19:33Z

Fixes#131721
Fixes#131893

PR #126108 removed process isolation from Collect, Collect0, and Collect1, allowing their generation assertions to observe GC state accumulated by earlier tests in the merged runner. Restore isolation because these tests require uncontested process-wide GC state.

Local x86 Checked investigation reproduced all three failures by accumulating leaked pinned handles in a shared process. The same failures occurred under FullOpt, while target-only runs, runs excluding AddrOfPinnedObject, and pin-and-free controls completed 10,000 iterations without failure, so this change preserves JIT-mode coverage instead of marking the tests JitOptimizationSensitive.

Validation:

Windows x64 and x86 Checked Core_Root and targeted GC test builds
Individual Collect, Collect0, and Collect1 wrappers
Full merged GC runner with the restored out-of-process dispatch

Note

This pull request description was prepared with GitHub Copilot.

These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

azure-pipelines · 2026-08-10T13:20:15Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-08-10T13:20:55Z

Tagging subscribers to this area: @anicka-net, @dotnet/gc
See info in area-owners.md if you want to be subscribed.

azure-pipelines · 2026-08-10T13:21:39Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Restores per-test process isolation for the GC Collect, Collect0, and Collect1 test projects so their generation assertions run with uncontested, process-wide GC state (preventing cross-test GC-state leakage in merged runners).

Changes:

Re-added <RequiresProcessIsolation>true</RequiresProcessIsolation> to Collect, Collect0, and Collect1 test project files.
Documented the isolation requirement inline in each project file with a brief rationale comment.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/GC/API/GC/Collect.csproj	Restores process isolation for the `Collect` test project to avoid shared-process GC state interference.
src/tests/GC/API/GC/Collect0.csproj	Restores process isolation for the `Collect0` test project to ensure GC generation checks are reliable.
src/tests/GC/API/GC/Collect1.csproj	Restores process isolation for the `Collect1` test project to prevent contamination from prior tests in merged runners.

Restore isolation for GC Collect tests
9b56074
These tests depend on process-wide GC state and cannot run reliably in the merged test runner. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f7186616-baa4-46ff-8c5e-2571610a7219

CopilotAI lite review requested due to automatic review settings August 10, 2026 13:19

github-actionsBot added the area-GC-coreclr label Aug 10, 2026

dotnet-policy-serviceBot assigned kkokosa Aug 10, 2026

Copilotstarted reviewing on behalf of kkokosa August 10, 2026 13:20 View session

kkokosa marked this pull request as ready for review August 10, 2026 13:21

CopilotAI reviewed Aug 10, 2026
View reviewed changes

kkokosa mentioned this pull request Aug 10, 2026
Test failure: GC/API/GC/Collect/Collect.dll #131721
Closed

jkoritzinsky approved these changes Aug 11, 2026
View reviewed changes

kkokosa merged commit 705bed2 into dotnet:mainAug 12, 2026
87 checks passed

kkokosa deleted the fix-131721-gc-collect-isolation branch August 12, 2026 06:38

dotnet-maestroBot mentioned this pull request Aug 13, 2026
[main] Source code updates from dotnet/runtime dotnet/dotnet#8272
Merged

dotnet-milestone-botBot added this to the 11.0-rc1 milestone Aug 13, 2026

janvorli mentioned this pull request Aug 17, 2026
GC.GetGeneration test fails under R2R with JitStressRegs=2 #132291
Open