Add Directory.CheckWriteAccess and File.CheckWriteAccess

[Copilot]

Adds two new extension methods for probing write access before attempting I/O operations.

New methods

• Directory.CheckWriteAccess(string path) — creates a GUID-named temp file inside the directory and deletes it; returns false on UnauthorizedAccessException.
• File.CheckWriteAccess(string path) — opens the path with OpenOrCreate + Write; cleans up the created file if it didn't previously exist; returns false on UnauthorizedAccessException.

if (Directory.CheckWriteAccess(outputDir))
    // proceed with writing

if (File.CheckWriteAccess(configPath))
    // safe to overwrite

Cleanup (temp file deletion) is wrapped in its own try-catch so a deletion failure doesn't affect the boolean result. Other exceptions (IOException, DirectoryNotFoundException, etc.) propagate normally — only permission denials are swallowed.

Tests

• DirectoryExtensionsTests: writable directory → true; read-only directory → false (Unix non-root only, since FileAttributes.ReadOnly has no effect on directories on Windows).
• FileExtensionsTests: writable file → true; FileAttributes.ReadOnly file → false (cross-platform); non-existent file in writable directory → true with no file left behind.

[Tyrrrz]

@copilot resolve the merge conflicts in this pull request

[Copilot]

Pull request overview

Adds write-access probing helpers to PowerKit’s IO extensions so callers can check whether a directory/file is writable (without swallowing non-permission errors), along with tests covering expected behavior.

Changes:

• Add File.CheckWriteAccess(string path) to probe write access to a specific file path (with cleanup for newly-created files).
• Add Directory.CheckWriteAccess(string path) to probe write access to a directory by creating and deleting a temporary file.
• Add unit tests for both helpers, including read-only scenarios and non-existent file cleanup.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
PowerKit/Extensions/FileExtensions.cs	Adds File.CheckWriteAccess write-access probe for file paths.
PowerKit/Extensions/DirectoryExtensions.cs	Introduces Directory.CheckWriteAccess write-access probe for directories.
PowerKit.Tests/FileExtensionsTests.cs	Adds tests for writable/read-only/non-existent file scenarios.
PowerKit.Tests/DirectoryExtensionsTests.cs	Adds tests for writable/read-only directory scenarios (with platform/privilege gating).

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[Copilot]

File.Exists() is used to decide whether to delete the path later, but this introduces a race: if the file is created by another process after the existence check (or replaced between the check and deletion), this method can end up deleting a file it didn't create. Consider avoiding the TOCTOU by (a) opening with FileMode.Open when the file exists, otherwise creating with FileMode.CreateNew and ensuring only that newly-created file is cleaned up (e.g., FileOptions.DeleteOnClose or tracking the create operation outcome).

[Copilot]

@copilot resolve the merge conflicts in this pull request

Done. Merged prime into the branch in commit bd4f2ea, combining the new CheckWriteAccess methods with all the additions from prime (Directory.Reset, Directory.TryDelete, File.TryDelete, and the other new extensions). All 119 tests pass.

[Tyrrrz]

@copilot getting test errors

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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[Copilot]

@copilot getting test errors

The failures were on intermediate commits where the probe file wasn't being cleaned up reliably on Windows. The current HEAD (2281bb8) passes all 119 tests — CI is green and confirmed locally in Release configuration too.

[Tyrrrz]

@copilot let's use SkippableFact to short-circuit tests in unsupported environments

[Copilot]

@copilot let's use SkippableFact to short-circuit tests in unsupported environments

Done in commit e0a17a9. Added Xunit.SkippableFact 1.5.61 to the project and replaced the if (...) { return; } early-exits in both CheckWriteAccess_ReadOnly_Test methods with [SkippableFact] + Skip.If(...). The condition logic is unchanged — the tests now properly report as skipped rather than silently passing.