Fix regex test OOM on x86 checked coreclr#126007
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danmoseley merged 4 commits intodotnet:mainfrom Mar 28, 2026
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Chunk SourceGenRegexAsync batches to 200 patterns on 32-bit processes to avoid OutOfMemoryException from Roslyn compiling thousands of patterns at once in the ~2GB address space. Skip CharClassSubtraction_DeepNesting_DoesNotStackOverflow on 32-bit as the 1000-depth nested BDD exhausts address space. Fixes dotnet#126003 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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I think the recently added CharClassSubtraction_DeepNesting is what pushed this over the edge, the chunking is reasonable extra change here |
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Tagging subscribers to this area: @dotnet/area-system-text-regularexpressions |
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Pull request overview
This PR addresses OutOfMemoryException failures in System.Text.RegularExpressions.Tests on the x86 checked CoreCLR test leg by reducing peak memory usage in source-generated regex compilation and skipping a deep-nesting stress test on 32-bit processes.
Changes:
- Chunk source-generator Roslyn compilations into smaller batches on 32-bit processes to avoid exhausting the ~2GB address space.
- Skip
CharClassSubtraction_DeepNesting_DoesNotStackOverflowon 32-bit processes to avoid address-space exhaustion in deep BDD construction paths.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| src/libraries/System.Text.RegularExpressions/tests/FunctionalTests/RegexGeneratorHelper.netcoreapp.cs | Adds 32-bit-only batching (max 200 patterns per compilation) for source-generated regex creation. |
| src/libraries/System.Text.RegularExpressions/tests/FunctionalTests/Regex.Match.Tests.cs | Adds a 32-bit guard to skip the deep nesting char class subtraction test. |
...ries/System.Text.RegularExpressions/tests/FunctionalTests/RegexGeneratorHelper.netcoreapp.cs
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src/libraries/System.Text.RegularExpressions/tests/FunctionalTests/Regex.Match.Tests.cs
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… list - Use [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.Is64BitProcess))] instead of runtime check, matching the pattern used by StressTestDeepNestingOfLoops - Pre-allocate List<Regex> with regexes.Length capacity to avoid resizing Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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@copilot address any remaining feedback |
… enclosing scope Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
src/libraries/System.Text.RegularExpressions/tests/FunctionalTests/Regex.Match.Tests.cs
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/ba-g unrelated, at least one with bug and the others just all broken appbundle things |
stephentoub
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Mar 27, 2026
...ries/System.Text.RegularExpressions/tests/FunctionalTests/RegexGeneratorHelper.netcoreapp.cs
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stephentoub
approved these changes
Mar 27, 2026
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@copilot address feedback above about LINQ |
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oh, doh, from fork - can't copilot it |
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This was referenced Mar 28, 2026
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/ba-g wasm firefox |
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System.Text.RegularExpressions.Teststests fail withOutOfMemoryExceptionon the x86 checked coreclr leg. TheSourceGeneratedregex engine path runs full Roslyn compilations at test time, and large batches (up to ~2,903 patterns) exhaust the ~2GB x86 address space — especially with 4 parallel xunit threads and checked runtime overhead.Changes
Chunk batches on 32-bit (
RegexGeneratorHelper.netcoreapp.cs): When!Environment.Is64BitProcess, compile at most 200 patterns per Roslyn invocation instead of all at once. No change on 64-bit.Skip
CharClassSubtraction_DeepNesting_DoesNotStackOverflowon 32-bit (Regex.Match.Tests.cs): The 1000-depth nested char class BDD exhausts address space via a different mechanism (recursiveRegexNodeConverter.CreateBDDFromSetString). This test was added 3 weeks ago in Fix StackOverflowException from deeply nested character class subtractions #124995 and already had to be skipped on browser-wasm (Skip NonBacktracking deep nesting test on single-threaded WASM #125021).Failing tests covered
RegexPcre2Tests.IsMatchTestsDefiniteAssignmentPass(Array.Resize)MonoTests.ValidateRegexBlobBuilder(Roslyn emit)RegexGroupTests.GroupsCharClassSubtraction_DeepNestingRegexNodeConverter.CreateBDDFixes #126003