Improve performance by skipping unnecessary normalisation (#3751)

[etc/vim.git] / src / black / files.py

diff --git a/src/black/files.py b/src/black/files.py
index 4e2209e557d2cc9c26d60db5d471c79e80a8f7da..ef6895ee3af5341c6e32b9ff0521426dd9107c59 100644 (file)
--- a/src/black/files.py
+++ b/src/black/files.py
@@ -276,15 +276,24 @@ def normalize_path_maybe_ignore(
     return root_relative_path
 
 
-def path_is_ignored(
-    path: Path, gitignore_dict: Dict[Path, PathSpec], report: Report
+def _path_is_ignored(
+    root_relative_path: str,
+    root: Path,
+    gitignore_dict: Dict[Path, PathSpec],
+    report: Report,
 ) -> bool:
+    path = root / root_relative_path
+    # Note that this logic is sensitive to the ordering of gitignore_dict. Callers must
+    # ensure that gitignore_dict is ordered from least specific to most specific.
     for gitignore_path, pattern in gitignore_dict.items():
-        relative_path = normalize_path_maybe_ignore(path, gitignore_path, report)
-        if relative_path is None:
+        try:
+            relative_path = path.relative_to(gitignore_path).as_posix()
+        except ValueError:
             break
         if pattern.match_file(relative_path):
-            report.path_ignored(path, "matches a .gitignore file content")
+            report.path_ignored(
+                path.relative_to(root), "matches a .gitignore file content"
+            )
             return True
     return False
 
@@ -326,7 +335,9 @@ def gen_python_files(
             continue
 
         # First ignore files matching .gitignore, if passed
-        if gitignore_dict and path_is_ignored(child, gitignore_dict, report):
+        if gitignore_dict and _path_is_ignored(
+            normalized_path, root, gitignore_dict, report
+        ):
             continue
 
         # Then ignore with `--exclude` `--extend-exclude` and `--force-exclude` options.