Add an implicit ".git/" line which git does internally.

This is useful if you want to list only the files that git would track.
It clearly doesn't track its own files.

Author: tewalds

gitignore_parser.py

@@ -15,7 +15,10 @@ def handle_negation(file_path, rules: Reversible["IgnoreRule"]):
 def parse_gitignore(full_path, base_dir=None):
     if base_dir is None:
         base_dir = dirname(full_path)
-    rules = []
+    rules = [
+        rule_from_pattern(".git/", base_path=_normalize_path(base_dir),
+                          source=(full_path, -1)),
+    ]
     with open(full_path) as ignore_file:
         counter = 0
         for line in ignore_file:

tests.py

@@ -19,6 +19,13 @@ def test_simple(self):
         self.assertTrue(matches('/home/michael/dir/main.pyc'))
         self.assertTrue(matches('/home/michael/__pycache__'))
 
+    def test_ignores_git_directory(self):
+        matches = _parse_gitignore_string('*.py', fake_base_dir='/home/michael')
+        self.assertFalse(matches('/home/michael/.gitignore'))
+        self.assertTrue(matches('/home/michael/.git'))
+        self.assertTrue(matches('/home/michael/.git/config'))
+        self.assertTrue(matches('/home/michael/.git/logs/refs/remotes/origin/HEAD'))
+
     def test_incomplete_filename(self):
         matches = _parse_gitignore_string('o.py', fake_base_dir='/home/michael')
         self.assertTrue(matches('/home/michael/o.py'))