Issue #15725: Skip git ignored files in ./mach update-manifest

tests/wpt/web-platform-tests/tools/manifest/manifest.py

@@ -85,6 +85,10 @@ def update(self, tree):
                 else:
                     new_type, manifest_items = old_type, self._data[old_type][rel_path]
             else:
+                # Issue #15725: Skip git ignored files
+                from vcs import Git
+                if Git.is_ignored(source_file.tests_root, source_file.rel_path):
+                    continue
                 new_type, manifest_items = source_file.manifest_items()
 
             if new_type in ("reftest", "reftest_node"):

tests/wpt/web-platform-tests/tools/manifest/vcs.py

@@ -25,6 +25,15 @@ def for_path(cls, path, url_base):
         except subprocess.CalledProcessError:
             return None
 
+    @staticmethod
+    def is_ignored(dir_base, rel_path):
+        git = Git.get_func(dir_base)
+        try:
+            git("check-ignore", "-q", rel_path)
+            return True
+        except subprocess.CalledProcessError:
+            return False
+
     def _local_changes(self):
         changes = {}
         cmd = ["status", "-z", "--ignore-submodules=all"]