diff --git a/src/black/files.py b/src/black/files.py
index c58970e53e3..ccd7f5e37f4 100644
--- a/src/black/files.py
+++ b/src/black/files.py
@@ -182,6 +182,19 @@ def normalize_path_maybe_ignore(
     return root_relative_path
 
 
+def path_is_ignored(
+    path: Path, gitignore_dict: Dict[Path, PathSpec], report: Report
+) -> bool:
+    for gitignore_path, pattern in gitignore_dict.items():
+        relative_path = normalize_path_maybe_ignore(path, gitignore_path, report)
+        if relative_path is None:
+            break
+        if pattern.match_file(relative_path):
+            report.path_ignored(path, "matches a .gitignore file content")
+            return True
+    return False
+
+
 def path_is_excluded(
     normalized_path: str,
     pattern: Optional[Pattern[str]],
@@ -212,18 +225,6 @@ def gen_python_files(
     `report` is where output about exclusions goes.
     """
 
-    def is_ignored(
-        gitignore_dict: Dict[Path, PathSpec], child: Path, report: Report
-    ) -> bool:
-        for _dir, _gitignore in gitignore_dict.items():
-            relative_path = normalize_path_maybe_ignore(child, _dir, report)
-            if relative_path is None:
-                break
-            if _gitignore is not None and _gitignore.match_file(relative_path):
-                report.path_ignored(child, "matches the .gitignore file content")
-                return True
-        return False
-
     assert root.is_absolute(), f"INTERNAL ERROR: `root` must be absolute but is {root}"
     for child in paths:
         normalized_path = normalize_path_maybe_ignore(child, root, report)
@@ -231,7 +232,7 @@ def is_ignored(
             continue
 
         # First ignore files matching .gitignore, if passed
-        if gitignore_dict is not None and is_ignored(gitignore_dict, child, report):
+        if gitignore_dict is not None and path_is_ignored(child, gitignore_dict, report):
             continue
 
         # Then ignore with `--exclude` `--extend-exclude` and `--force-exclude` options.