Add function to strip trailing path separators and preserve root paths

[karthiknadig]

Fixes #278

[Copilot]

Pull request overview

This PR adds a new utility function strip_trailing_separator() to handle trailing path separators from paths while preserving root paths, addressing issue #278. The function provides a lightweight alternative to norm_case() when only trailing separator removal is needed without full path normalization.

Changes:

• Added strip_trailing_separator() function with platform-specific implementations for Windows and Unix
• Enhanced documentation for norm_case(), resolve_symlink(), and expand_path() with detailed usage notes and cross-references
• Added comprehensive test coverage for the new function on both Unix and Windows platforms

Comments suppressed due to low confidence (2)

crates/pet-fs/src/path.rs:37

• The hardcoded length check > 3 is a magic number that isn't clearly explained. Consider adding a comment explaining this preserves Windows root paths like C:\ (3 characters) or using a named constant. Additionally, this doesn't account for edge cases like C:/ (forward slashes on Windows) which would have length 3 but should also be preserved.

        while result.len() > 3 && (result.ends_with('\\') || result.ends_with('/')) {
            result.pop();
        }

crates/pet-fs/src/path.rs:354

• The Windows tests are missing coverage for important edge cases: UNC paths (\\?\C:\path\), network paths (\\server\share\), paths with forward slashes that equal length 3 (C:/), and paths with mixed trailing separators (C:\path\/). These edge cases should be tested given the complexity of Windows path handling.

        assert_eq!(strip_trailing_separator("C:\\"), PathBuf::from("C:\\"));

[Copilot]

The Windows implementation has a logic error. It preserves paths longer than 3 characters (e.g., C:\) but will fail for UNC paths like \\server\share\ (length > 3) and network paths like \\server\ which should be preserved as root paths. The check should be more sophisticated to handle UNC/network paths (\\?\..., \\server\...) similar to how normalize_case_windows() uses Path::parent() for robust root detection.

This issue also appears in the following locations of the same file:

• line 35
• line 354

Suggested change

	// On Windows, preserve root paths like "C:\"
	let mut result = path_str.to_string();
	while result.len() > 3 && (result.ends_with('\\') || result.ends_with('/')) {
	// On Windows, preserve root paths (e.g. "C:\", "\\server\", "\\?\C:\")
	let mut result = path_str.to_string();
	while (result.ends_with('\\') || result.ends_with('/'))
	&& Path::new(&result).parent().is_some()
	{