[adamsitnik]

Summary

• Set InheritedHandles = [] in the shared factory for all five Process.Run* and Process.StartAndForget overloads that accept a file name and argument collection. Overloads accepting a caller-provided ProcessStartInfo remain unchanged.
• Document the new default and add seven regression cases covering every affected API, including synchronous/asynchronous execution and both silent values where applicable.
• Simplify 14 call sites across 13 runtime-test files touched by Modernize runtime test process orchestration with .NET 11 APIs #136474 to use the file-name/arguments overloads. Preserve command wrapping, diagnostics, timeouts, and captured output; retain ProcessStartInfo where custom settings are needed.

Additional handle inheritance now requires using a ProcessStartInfo overload. Standard-handle behavior is unchanged.

Validation

Tested locally on Windows x64:

• .\dotnet.cmd build src\libraries\System.Diagnostics.Process\src\System.Diagnostics.Process.csproj -p:Configuration=Release -p:RunAnalyzersInBuild=true passed with no warnings or errors.
• The seven new regression cases failed without the product change and passed with it.
• .\dotnet.cmd build /t:Test src\libraries\System.Diagnostics.Process\tests\System.Diagnostics.Process.Tests.csproj -p:Configuration=Release completed with 700 passed, 2 skipped, and 1 failed. The failure was ProcessHandlesTests.ChildProcess_CanBreakAwayFromJob(killOnParentExit: False): Windows returned Win32Exception(5): Access is denied in the WindowsProcessStartArguments callback, outside the convenience overloads changed here.
• All modified runtime-test sources compiled using the existing checked baseline. The three modified NativeAOT caller projects were also compiled as managed assemblies.
• .\dotnet.cmd build src\tests\Common\XUnitLogChecker\XUnitLogChecker.csproj -p:Configuration=Release -p:RunAnalyzersInBuild=true passed with no warnings or errors.
• .\dotnet.cmd build src\tests\run.cs -o artifacts\process-overload-runner -p:RunAnalyzersInBuild=true passed.
• Binder resolution-flow tests passed: 32 completed cases, including 21 isolated process launches. R2RDump tests passed. These runs used the locally built System.Diagnostics.Process assembly through CORE_LIBRARIES.
• Twelve additional local checks against the actual runner/checker helpers passed, covering executable exit codes, .cmd wrapping, paths/arguments containing spaces, empty arguments, ComSpec fallback, stdout/stderr capture, diagnostics, and startup failures. The loaded Process assembly was checked against the local build's SHA-256 hash.
• git diff --check passed.

Linux-specific and NativeAOT-specific scenarios were compiled but not executed. The full runtime test suite was not run.

Local measurements

A short Windows BenchmarkDotNet run compared an unrestricted ProcessStartInfo control with the restricted file-name/arguments overloads, launching cmd.exe /d /c exit 0.

Operation	Unrestricted ProcessStartInfo	Restricted convenience overload
Run	16.26 ms	15.49 ms
RunAndCaptureText	15.26 ms	15.89 ms

This used the same locally built Process assembly, the in-process emit toolchain, three warmups, eight measured iterations, and 128 invocations per iteration. It is not a historical-binary comparison, and the short run does not establish a performance improvement or regression.

Note

This pull request description and code changes were generated with GitHub Copilot.

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[jkotas]

This is breaking change, correct? What will be the justification for the breaking change?