Skip Start_Disposed_ThrowsObjectDisposedException on Apple mobile platforms

[steveisok]

Fix

Adds [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)] to Start_Disposed_ThrowsObjectDisposedException.

Why

Process.Start() on iOS/tvOS/MacCatalyst throws PlatformNotSupportedException (process launching is unsupported) before checking disposal state. The test expects ObjectDisposedException which never fires, causing a deterministic failure across 7 legs in every runtime-extra-platforms rolling build.

This follows the same [SkipOnPlatform] pattern used by 20+ other tests in the same file.

Fixes #126654

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[Copilot]

Pull request overview

Skips ProcessTests.Start_Disposed_ThrowsObjectDisposedException on Apple mobile platforms where Process.Start() is unsupported and deterministically throws PlatformNotSupportedException before disposal checks, causing consistent test failures in runtime-extra-platforms.

Changes:

• Added [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst, ...)] to Start_Disposed_ThrowsObjectDisposedException.

[steveisok]

@kotlarmilos should this not apply to maccatalyst?

[github-actions]

🤖 Copilot Code Review — PR #126655

Note

This review was generated by GitHub Copilot.

Holistic Assessment

Motivation: The problem is real and verified — Process.Start() throws PlatformNotSupportedException on iOS/tvOS before checking disposal state (line 1167–1169 in Process.cs), so the test's ObjectDisposedException assertion never fires. Skipping on those platforms is the correct fix.

Approach: Adding [SkipOnPlatform] follows the established pattern used by 20+ tests in the same file. This is the right approach for a test that exercises behavior impossible on unsupported platforms.

Summary: ⚠️ Needs Human Review. The iOS/tvOS skip is correct, but MacCatalyst should likely be removed from the skip list. The author has already raised this question in the PR comments. A human reviewer should confirm.

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Detailed Findings

⚠️ MacCatalyst may be incorrectly included in the skip

ProcessUtils.PlatformSupportsProcessStartAndKill (ProcessUtils.cs:15–16) is:

=> !((OperatingSystem.IsIOS() && !OperatingSystem.IsMacCatalyst()) || OperatingSystem.IsTvOS());

On MacCatalyst, IsIOS() = true and IsMacCatalyst() = true, so:

• (true && !true) || false → false
• !false → true — MacCatalyst is supported

This is consistent with the [SupportedOSPlatform("maccatalyst")] attribute on Process.Start() (line 1159). On MacCatalyst the code reaches CheckDisposed() (line 1173) and would correctly throw ObjectDisposedException — meaning the test should pass there.

The skip attribute should likely be:

[SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Process.Start() is not supported on iOS and tvOS.")]

Note: The author has already flagged this question in the PR comments ("should this not apply to maccatalyst?"). The issue description's mention of MacCatalyst failures may stem from other tests or a different root cause — worth verifying with CI data.

✅ iOS and tvOS skip is correct

Verified via code analysis: Process.Start() → PlatformSupportsProcessStartAndKill returns false on iOS (non-MacCatalyst) and tvOS → PlatformNotSupportedException thrown at line 1169, before CheckDisposed() at line 1173. The test cannot pass on these platforms.

✅ Other disposal tests are unaffected

The sibling tests (StandardInput_Disposed, StandardOutput_Disposed, StandardError_Disposed, CancelOutputRead_Disposed, CancelErrorRead_Disposed) all call CheckDisposed() as their first operation with no platform guard before it, so they correctly throw ObjectDisposedException on all platforms, including iOS/tvOS. Only Start_Disposed needs this skip.

✅ Pattern consistency

The attribute follows the same [SkipOnPlatform(...)] pattern used throughout the file. The skip reason message is clear and accurate.

Generated by Code Review for issue #126655 · ◷

[vitek-karas]

#126631 does the same... not a problem necessarily.