Enable out-of-process tests for CoreCLR browser WASM

[radekdoulik]

Summary

CoreCLR browser-WASM cannot use fork or managed process creation, so runtime
tests marked RequiresProcessIsolation were omitted from merged runners. This
PR enables those tests without adding Node-specific process APIs to managed
runtime code:

• the merged runner emits a plan using its existing filtering and striping;
• the host Bash or Batch script executes each existing per-test wrapper in a
  fresh child shell;
• the merged runner imports the child results into its normal xUnit report.

The PR also includes the runtime-test infrastructure, platform gating, and
focused runtime/test fixes needed to make priority-0 and priority-1 CoreCLR
browser-WASM coverage pass consistently.

This reuses the existing CoreCLR corerun wrappers; it does not introduce a
parallel browserhost scheduler or duplicate per-test execution semantics.

Execution model

The browser run has three phases:

1. Plan: the generated merged runner writes the selected out-of-process
   assembly paths.
2. Execute: the host runs each existing .sh or .cmd wrapper and records
   its output, exit code, pass/skip state, and skip reason.
3. Import: the normal merged run executes in-process tests and reports the
   precomputed child outcomes through the existing xUnit summary.

Existing wrappers remain authoritative for test arguments, environment
variables, pre/post commands, expected exit codes, and per-test timeouts.
Merged-runner arguments and stripe state are cleared while child wrappers run
and restored afterward.

The result format is versioned and bound to a per-run token. Missing plans,
wrappers, results, malformed records, or stale tokens fail as infrastructure
errors. A child in which every test is skipped is reported as skipped rather
than passed. Empty plan/status environment settings are treated as unset.

The host orchestration marker is emitted only for CoreCLR browser-WASM merged
runners that contain out-of-process tests.

Browser-WASM enablement and fixes

• Discovery: only buildable projects with runnable wrappers are added to
  merged-runner OOP plans.
• Interpreter: InterpreterTester runs Interpreter.dll directly through
  the host OOP path with the required interpreter environment instead of
  calling Process.Start inside the browser.
• ReadyToRun assets: host Crossgen2 assets are staged for
  cross-architecture runs, and emitted WASM components, including composite
  output, are validated.
• Composite ReadyToRun tests: affected CoreCLR browser tests carry an
  ActiveIssue for
  #131767. Their browser
  projects do not force Crossgen2, allowing the managed wrapper to report the
  skip before CoreCLR probes the unsupported composite WebCIL layout. Other
  targets retain their existing composite R2R coverage.
• Host paths: Batch orchestration retains Windows paths for host file
  operations while exposing Unix-style absolute paths to browser managed code.
• Multithreading: FeatureMultithreading is available during test project
  evaluation. Tests whose only requirement is managed multithreading use that
  global capability, so they remain excluded on single-threaded targets and
  become buildable when threads are enabled.
• Precise platform scope: tests requiring background/server GC, native
  threads, child processes, unsupported browser APIs, mutable host filesystem
  behavior, or impractical interpreter workloads are gated or excluded at the
  narrowest applicable level.
• Shutdown lifecycle: the CoreCLR browser shutdown wrapper is installed
  from Emscripten preRun, after native exports are bound, so explicit
  Environment.Exit values are preserved and no finalization work is
  scheduled while the runtime exits.
• Background GC information test: the browser CoreCLR
  GetGCMemoryInfo test carries an ActiveIssue for
  #131766, which tracks the
  assertion from requesting GCKind.Background when background GC is not
  compiled. This PR does not change the product behavior.
• Test assumptions: focused adaptations remove incidental process,
  threading, filesystem, and host-tool assumptions while preserving the
  behavior each test is intended to cover.
• Post-merge CI coverage: build 1528104 exposed 30 deterministic OOP
  failures after newer main changes activated more browser scenarios. The
  eager-fixup lock-order failure is fixed on main by
  #131355. Composite WebCIL
  loading and background-GC information remain tracked separately by [wasm][CoreCLR][R2R] Composite WebCIL images request an unsupported loaded PE layout #131767
  and [browser][CoreCLR] GC.GetGCMemoryInfo(GCKind.Background) asserts when background GC is unavailable #131766. The Int128 field-layout correctness fix is proceeding in
  #131421; other unsupported
  cases are gated only for CoreCLR browser-WASM with explicit re-enable
  prerequisites.

No shipping public API is added.

Deferred scope

Per-test native assets, UCO thunk generation, and native relinking are
intentionally deferred. Tests that need them remain guarded by their existing
tracking issues.

The remaining non-multithreading/non-relinking exclusions were audited:
41 represent recoverable coverage and 16 exercise browser-inapplicable
contracts. The recoverable set and its prerequisites are tracked by
#131321, with links from each
suppression site. The newly exposed native-relinking test remains tracked by
#123946.

Validation

The following complete-suite results were recorded before the two product fixes
were moved to their dedicated tracking issues:

CoreCLR browser-WASM run	Total	Passed	Skipped	Failed
Priority 0 after the main merge	3,970	3,412	558	0
Priority 0 OOP subset	485	408	77	0
Earlier full priority 0+1 validation	14,726	13,850	876	0
Earlier priority 0+1 OOP subset	740	651	89	0

Current-head validation after removing those fixes:

• rebuilt the Checked CoreCLR browser-WASM runtime and libraries with zero
  warnings or errors;
• cleanly built all ten affected browser test projects;
• ran all ten generated wrappers against the unfixed runtime: every wrapper
  exited with the expected status and reported [browser][CoreCLR] GC.GetGCMemoryInfo(GCKind.Background) asserts when background GC is unavailable #131766 or [wasm][CoreCLR][R2R] Composite WebCIL images request an unsupported loaded PE layout #131767 through the
  OOP skip-status protocol, without either runtime assertion;
• verified that the shared non-R2R browser BasicTest remains enabled;
• verified on macOS that the R2R variant still forces Crossgen2, emits and
  validates its composite image, and passes.

Additional earlier validation:

• composite and non-composite WASM ReadyToRun output;
• native NativeLibraryTests asset staging;
• plan/import success, failure, filtering, striping, stale/malformed/missing
  records, environment-sensitive wrappers, and all-skipped children;
• unset, empty, and non-empty plan/status environment settings;
• direct browser-WASM InterpreterTester execution under Node;
• generated Bash syntax and generated Batch structure/path conversion;
• Checked browser runtime rebuild plus a fresh priority-0 payload and test
  layout after the main merge;
• all 22 new gates across CoreCLR browser, WASI, desktop, and Mono browser
  evaluations, preserving the pre-existing Mono ReadyToRun exclusions;
• the complete 72-runner Node run, including the ReadyToRun, base services,
  JIT, Loader, and tracing work items that failed in build 1528104.

Representative CoreCLR browser library suite	Total	Passed	Skipped	Failed
System.Threading.Timer.Tests	33	16	17	0
System.Runtime.InteropServices.JavaScript.Tests	476	474	2	0
System.Reflection.Emit.Tests (Debug)	2,028	2,017	11	0
System.Runtime.Tests (Debug)	75,726	75,559	167	0

The generated Batch path has been inspected and generated successfully but
still requires execution on Windows CI.

Note

This pull request description was updated with GitHub Copilot.

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Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
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[Copilot]

Pull request overview

This PR extends the CoreCLR browser-WASM test execution pipeline to support “out-of-process” (process-isolated) tests by adding a plan+execute orchestration flow: the merged managed runner can emit an OOP plan, host-side scripts run the existing per-test wrappers in fresh processes, and the merged runner then imports the precomputed wrapper results during the main test run.

Changes:

• Add a build-time marker file (*.HasOutOfProcessTests) for CoreCLR browser merged runners that have OOP tests.
• Update the merged runner codegen to support a “planning mode” (write OOP assembly paths instead of executing) and to route OOP tests through a precomputed-result import path on Browser.
• Update browser Windows (.cmd) and Unix (.sh) execution scripts to run the plan phase, execute OOP wrappers, write versioned result files with a per-run token, then run the merged runner to import results.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/tests/Common/XUnitWrapperGenerator/XUnitWrapperGenerator.props	Writes a HasOutOfProcessTests marker for CoreCLR+browser merged runners that contain OOP tests.
src/tests/Common/XUnitWrapperGenerator/XUnitWrapperGenerator.cs	Emits new generated-runner behavior: per-test executors with an optional plan-writer parameter; planning mode for OOP selection; Browser guard when orchestration is missing.
src/tests/Common/XUnitWrapperGenerator/ITestInfo.cs	Adds plan-writing support to the reporting wrapper; exposes OOP assembly path for plan emission.
src/tests/Common/CoreCLRTestLibrary/OutOfProcessTest.cs	Adds env-var plumbing and precomputed-result import so Browser can “run” OOP tests without forking.
src/tests/Common/CLRTest.Execute.Batch.targets	Adds Windows browser orchestration: plan phase, wrapper execution, result-file generation, then merged runner import phase.
src/tests/Common/CLRTest.Execute.Bash.targets	Adds Unix browser orchestration mirroring the batch logic: plan, run wrappers, write result files, then run merged runner to import.

[Copilot]

Pull request overview

Copilot reviewed 123 out of 124 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 123 out of 124 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 123 out of 124 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 133 out of 134 changed files in this pull request and generated no new comments.

Suppressed comments (1)

src/tests/Common/XUnitWrapperGenerator/ITestInfo.cs:557

• StandaloneTestReporting.WrapTestExecutionWithReporting sets the outOfProcessTestExecuted flag to true before running testExecution. For wrapper ITestInfo types that call WrapTestExecutionWithReporting even when the underlying test is skipped (e.g., TestWithCustomDisplayName wraps an inner ConditionalTest and still calls WrapTestExecutionWithReporting even on the skip path), this can incorrectly mark an all-skipped child as “executed”, preventing __TestOutOfProcessStatusFile from being written and causing the parent to report the child as passed instead of skipped.

    public CodeBuilder WrapTestExecutionWithReporting(CodeBuilder testExecution, ITestInfo test)
    {
        CodeBuilder builder = new();
        builder.AppendLine($"{_testExecutedLocalIdentifier} = true;");
        builder.Append(testExecution);

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[jkotas]

Is there a reason for why we are using the csproj conditions and not PlatformDetection.IsMultithreadingSupported ? We prefer the PlatformDetection conditions where posssible.

[jkotas]

Got copilot to fix that

https://github.com/dotnet/runtime/tasks/2e7c23e6-e0f1-4bf2-9d8b-43dbfd95aaa6