🐛 Fix Windows path prefix stripping for bsdtar compat

Disable MSYS2 automatic path conversion in the pnatar wrapper to
prevent mangling of Windows absolute paths (\\?\, \\.\, drive letters)
passed by bsdtar's test_windows. Add cfg(windows) tests covering
all 8 path prefix types from test_windows.c.

Author: ChanTsune

.github/scripts/pnatar-wrapper.sh

@@ -23,4 +23,11 @@ for arg in "$@"; do
   esac
 done
 
+# Prevent MSYS2 from converting POSIX-style path arguments to Windows paths
+# when launching the native Windows pna.exe binary. Without this, paths like
+# /path/to/file get mangled to C:\msys64\path\to\file, breaking bsdtar's
+# test_windows which passes 8 varieties of Windows absolute paths.
+export MSYS_NO_PATHCONV=1
+export MSYS2_ARG_CONV_EXCL='*'
+
 exec "$pna_bin" --log-level error experimental stdio --unstable "${expanded[@]}"

cli/src/command/core/path.rs

@@ -534,4 +534,111 @@ mod tests {
         let editor = PathnameEditor::new(Some(2), None, false, true);
         assert!(editor.edit_entry_name(Path::new("./a")).is_none());
     }
+
+    // --- Windows path prefix stripping (bsdtar test_windows compat) ---
+    //
+    // bsdtar's strip_absolute_path() strips Windows API prefixes, drive letters,
+    // and leading separators. On Windows, Rust's Path::components() correctly
+    // parses these as Prefix/RootDir components, which sanitize_preserve_curdir
+    // filters out — producing the same result as bsdtar.
+    //
+    // These 8 types correspond to bsdtar's test_windows.c mkfullpath() types.
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type0_forward_slash_absolute() {
+        // Type 0: /path/to/file — leading / stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("/msys64/tmp/file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type1_backslash_absolute() {
+        // Type 1: \path\to\file — leading \ stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("\\msys64\\tmp\\file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type2_drive_forward_slash() {
+        // Type 2: C:/path/to/file — C: and / stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("C:/msys64/tmp/file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type3_drive_backslash() {
+        // Type 3: C:\path\to\file — C: and \ stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("C:\\msys64\\tmp\\file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type4_device_forward_slash() {
+        // Type 4: //./C:/path/to/file — //./ and C: and / stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("//./C:/msys64/tmp/file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type5_device_backslash() {
+        // Type 5: \\.\C:\path\to\file — \\.\ and C: and \ stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("\\\\.\\C:\\msys64\\tmp\\file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type6_verbatim_forward_slash() {
+        // Type 6: //?/C:/path/to/file — //?/ and C: and / stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("//?/C:/msys64/tmp/file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_type7_verbatim_backslash() {
+        // Type 7: \\?\C:\path\to\file — \\?\ and C: and \ stripped
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor
+            .edit_entry_name(Path::new("\\\\?\\C:\\msys64\\tmp\\file"))
+            .unwrap();
+        assert_eq!(name.as_str(), "msys64/tmp/file");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn editor_windows_backslash_to_forward_slash_conversion() {
+        // bsdtar converts \ to / in entry names; pna's join_components_forward_slash
+        // achieves the same by reconstructing paths with / separators.
+        let editor = PathnameEditor::new(None, None, false, true);
+        let name = editor.edit_entry_name(Path::new("C:\\a\\b\\c")).unwrap();
+        assert_eq!(name.as_str(), "a/b/c");
+    }
 }