[tvOS] Skip symlink and named pipe tests that fail on iOS/tvOS

[Copilot]

tvOS (and iOS) raise UnauthorizedAccessException when creating symbolic links and return errors for mkfifo, causing GetFileType_SymbolicLink and GetFileType_NamedPipe to fail consistently on tvOS/arm64 CI legs.

Changes

• GetFileType_SymbolicLink: Replace [Fact] with [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))] — skips on any platform where symlink creation is not permitted (tvOS, unprivileged environments)
• GetFileType_NamedPipe: Add [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "iOS/tvOS blocks binding to UNIX sockets")] — consistent with the identical skip applied to NamedPipe_ReadWrite in DevicesPipesAndSockets.cs

Description

SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink and GetFileType_NamedPipe were unconditionally running on all Unix platforms. tvOS prohibits symbolic link creation (EPERM) and does not support mkfifo, causing both tests to fail on every tvOS CI run across both CoreCLR and Mono legs.

Customer Impact

No customer impact; this is a test-only fix to stop recurring false CI failures on tvOS.

Regression

No — these tests never passed on tvOS. The failures surfaced as the tvOS leg became more active in CI.

Testing

The fixes mirror already-established skip patterns for the same platforms elsewhere in the same test assembly. No new logic is introduced in product code.

Risk

Minimal. Test-only change, no product code modified. The MountHelper.CanCreateSymbolicLinks guard is already widely used across the symbolic link test suite; SkipOnPlatform for iOS/tvOS is an established pattern in the same file's sibling tests.

Package authoring no longer needed in .NET 9

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Keep in mind that we still need package authoring in .NET 8 and older versions.

Original prompt

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This section details on the original issue you should resolve

<issue_title>UnauthorizedAccessException creating symlink on tvOS device (Operation not permitted)</issue_title>
<issue_description>Suggested labels: Known Build Error, test-failure, os-tvos, arch-arm64, untriaged

Note: This issue was automatically generated by AI-Test-Triage. Please review and triage accordingly.

Build Information

Build: 20260309.1, 20260310.2

Build error leg or test failing: System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink, System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_NamedPipe, System.IO.FileSystem.Tests.WorkItemExecution

Affected CI jobs: build_tvos_arm64_Release_AllSubsets_CoreCLR, build_tvOS_arm64_Release_AllSubsets_Mono

Causing Commit Range Information

Commit range: {TODO: Insert commit range or link to changes}

Summary

• UnauthorizedAccessException ('Operation not permitted') occurs when creating symbolic links during System.IO tests.
• Failures reproducible on tvOS device runs in build_tvos_arm64_Release_AllSubsets_CoreCLR (tvos/arm64).
• Tests are executed via XHarness/mlaunch; test harness reports XHarness exit code 1 (TESTS_FAILED).
• Device interaction logs sometimes show mlaunch exiting with code 137, concurrent with the symlink failures.
• Root failure surfaces in System.IO.File.CreateSymbolicLink invoked from SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink.

Failure Statistics

Note: These statistics are based on the configured time range and might not reflect the full history of the failure.

• Occurrence Count: 12
• First Failure: 2026-03-10 07:35:08 UTC
• Last Failure: 2026-03-11 08:06:52 UTC

Work Items

Showing 10 most recent of 12 occurrences

Work Item	Console Log	Build	Job Name
System.IO.FileSystem.Tests Work Item	View Extract [00:57:32.8313560] 2026-03-09 21:57:32.892 System.IO.FileSystem.Tests[13824:11381713] [FAIL] System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink [00:57:32.8331760] 2026-03-09 21:57:32.893 System.IO.FileSystem.Tests[13824:11381713] System.UnauthorizedAccessException : Access to the path '/private/var/mobile/Containers/Data/Application/B4A6FCC5-9050-463B-8950-5CABC94B81D8/tmp/#SafeFileHandle_GetFileType_Unix_w1d2lkuk.cut/GetFileType_SymbolicLink_48_4n3u3cep' is denied. [00:57:32.8332330] ---- System.IO.IOException : Operation not permitted [00:57:32.8332590] at Interop.ThrowExceptionForIoErrno(ErrorInfo errorInfo, String path, Boolean isDirError) [00:57:32.8332710] 2026-03-09 21:57:32.893 System.IO.FileSystem.Tests[13824:11381713] at Interop.CheckIo(Int64 result, String path, Boolean isDirError) [00:57:32.8332810] at System.IO.File.CreateSymbolicLink(String path, String pathToTarget) ... [00:58:52] dbug: Saving diagnostics data to '/tmp/helix/working/AF5009A4/w/B0360953/e/diagnostics.json' XHarness exit code: 1 (TESTS_FAILED) ... [00:58:35] dbug: Process mlaunch exited with 137 [00:58:35] dbug: Test run completed Full Log	20260309.1	build_tvos_arm64_Release_AllSubsets_CoreCLR
System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink	View Extract [01:14:52.1100100] Test collection for System.IO.Tests.SafeFileHandle_GetFileType_Unix [01:14:52.1303710] 2026-03-09 22:14:52.261 System.IO.FileSystem.Tests[15414:12129812] [FAIL] System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink [01:14:52.1303870] 2026-03-09 22:14:52.262 System.IO.FileSystem.Tests[15414:12129812] System.UnauthorizedAccessException : Access to the path '/private/var/mobile/Containers/Data/Application/E898CCCE-58BD-4C37-972C-D1B8DB22D2FC/tmp/#SafeFileHandle_GetFileType_Unix_5ihimqbm.qpy/GetFileType_SymbolicLink_48_9mv0gog9' is denied. [01:14:52.1303920] ---- System.IO.IOException : Operation not permitted [01:14:52.1303970] at System.IO.File.CreateSymbolicLink(String path, String pathToTarget) [01:14:52.1317430] 2026-03-09 22:14:52.262 System.IO.FileSystem.Tests[15414:12129812] at System.IO.Tests.SafeFileHandle_GetFileType_Unix.GetFileType_SymbolicLink() [01:14:52.1317860] at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args) [01:14:52.1317930] at Syst...

• Fixes UnauthorizedAccessException creating symlink on tvOS device (Operation not permitted) #125490

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[adamsitnik]

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[Copilot]

Pull request overview

Adjusts Unix GetFileType tests to avoid consistent failures on iOS/tvOS where symlinks and FIFOs aren’t permitted/supported, reducing false CI failures on tvOS/arm64.

Changes:

• Skip GetFileType_NamedPipe on iOS/tvOS.
• Gate GetFileType_SymbolicLink behind MountHelper.CanCreateSymbolicLinks.

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[adamsitnik]

For some reason all CI legs are cancelled, I am going to close and re-open the PR..

[adamsitnik]

LGTM assuming the tests are going to pass.

To other reviewers: I've checked how other symlink/mkfifo tests are annotated and just asked Copilot to apply these annotations for me.