GH-73435: Add `pathlib.PurePath.full_match()` (#114350)

In 49f90ba we added support for the recursive wildcard `**` in
`pathlib.PurePath.match()`. This should allow arbitrary prefix and suffix
matching, like `p.match('foo/**')` or `p.match('**/foo')`, but there's a
problem: for relative patterns only, `match()` implicitly inserts a `**`
token on the left hand side, causing all patterns to match from the right.
As a result, it's impossible to match relative patterns from the left:
`PurePath('foo/bar').match('bar/**')` is true!

This commit reverts the changes to `match()`, and instead adds a new
`full_match()` method that:

- Allows empty patterns
- Supports the recursive wildcard `**`
- Matches the *entire* path when given a relative pattern

1 files changed, 75 insertions, 23 deletions

diff --git a/Lib/test/test_pathlib/test_pathlib_abc.py b/Lib/test/test_pathlib/test_pathlib_abc.py
index 199718a..364f776 100644
--- a/Lib/test/test_pathlib/test_pathlib_abc.py
+++ b/Lib/test/test_pathlib/test_pathlib_abc.py
@@ -249,29 +249,8 @@ class DummyPurePathTest(unittest.TestCase):
         self.assertFalse(P('/ab.py').match('/a/*.py'))
         self.assertFalse(P('/a/b/c.py').match('/a/*.py'))
         # Multi-part glob-style pattern.
-        self.assertTrue(P('a').match('**'))
-        self.assertTrue(P('c.py').match('**'))
-        self.assertTrue(P('a/b/c.py').match('**'))
-        self.assertTrue(P('/a/b/c.py').match('**'))
-        self.assertTrue(P('/a/b/c.py').match('/**'))
-        self.assertTrue(P('/a/b/c.py').match('/a/**'))
-        self.assertTrue(P('/a/b/c.py').match('**/*.py'))
-        self.assertTrue(P('/a/b/c.py').match('/**/*.py'))
+        self.assertFalse(P('/a/b/c.py').match('/**/*.py'))
         self.assertTrue(P('/a/b/c.py').match('/a/**/*.py'))
-        self.assertTrue(P('/a/b/c.py').match('/a/b/**/*.py'))
-        self.assertTrue(P('/a/b/c.py').match('/**/**/**/**/*.py'))
-        self.assertFalse(P('c.py').match('**/a.py'))
-        self.assertFalse(P('c.py').match('c/**'))
-        self.assertFalse(P('a/b/c.py').match('**/a'))
-        self.assertFalse(P('a/b/c.py').match('**/a/b'))
-        self.assertFalse(P('a/b/c.py').match('**/a/b/c'))
-        self.assertFalse(P('a/b/c.py').match('**/a/b/c.'))
-        self.assertFalse(P('a/b/c.py').match('**/a/b/c./**'))
-        self.assertFalse(P('a/b/c.py').match('**/a/b/c./**'))
-        self.assertFalse(P('a/b/c.py').match('/a/b/c.py/**'))
-        self.assertFalse(P('a/b/c.py').match('/**/a/b/c.py'))
-        self.assertRaises(ValueError, P('a').match, '**a/b/c')
-        self.assertRaises(ValueError, P('a').match, 'a/b/c**')
         # Case-sensitive flag
         self.assertFalse(P('A.py').match('a.PY', case_sensitive=True))
         self.assertTrue(P('A.py').match('a.PY', case_sensitive=False))
@@ -279,9 +258,82 @@ class DummyPurePathTest(unittest.TestCase):
         self.assertTrue(P('/a/b/c.py').match('/A/*/*.Py', case_sensitive=False))
         # Matching against empty path
         self.assertFalse(P('').match('*'))
-        self.assertTrue(P('').match('**'))
+        self.assertFalse(P('').match('**'))
         self.assertFalse(P('').match('**/*'))
 
+    def test_full_match_common(self):
+        P = self.cls
+        # Simple relative pattern.
+        self.assertTrue(P('b.py').full_match('b.py'))
+        self.assertFalse(P('a/b.py').full_match('b.py'))
+        self.assertFalse(P('/a/b.py').full_match('b.py'))
+        self.assertFalse(P('a.py').full_match('b.py'))
+        self.assertFalse(P('b/py').full_match('b.py'))
+        self.assertFalse(P('/a.py').full_match('b.py'))
+        self.assertFalse(P('b.py/c').full_match('b.py'))
+        # Wildcard relative pattern.
+        self.assertTrue(P('b.py').full_match('*.py'))
+        self.assertFalse(P('a/b.py').full_match('*.py'))
+        self.assertFalse(P('/a/b.py').full_match('*.py'))
+        self.assertFalse(P('b.pyc').full_match('*.py'))
+        self.assertFalse(P('b./py').full_match('*.py'))
+        self.assertFalse(P('b.py/c').full_match('*.py'))
+        # Multi-part relative pattern.
+        self.assertTrue(P('ab/c.py').full_match('a*/*.py'))
+        self.assertFalse(P('/d/ab/c.py').full_match('a*/*.py'))
+        self.assertFalse(P('a.py').full_match('a*/*.py'))
+        self.assertFalse(P('/dab/c.py').full_match('a*/*.py'))
+        self.assertFalse(P('ab/c.py/d').full_match('a*/*.py'))
+        # Absolute pattern.
+        self.assertTrue(P('/b.py').full_match('/*.py'))
+        self.assertFalse(P('b.py').full_match('/*.py'))
+        self.assertFalse(P('a/b.py').full_match('/*.py'))
+        self.assertFalse(P('/a/b.py').full_match('/*.py'))
+        # Multi-part absolute pattern.
+        self.assertTrue(P('/a/b.py').full_match('/a/*.py'))
+        self.assertFalse(P('/ab.py').full_match('/a/*.py'))
+        self.assertFalse(P('/a/b/c.py').full_match('/a/*.py'))
+        # Multi-part glob-style pattern.
+        self.assertTrue(P('a').full_match('**'))
+        self.assertTrue(P('c.py').full_match('**'))
+        self.assertTrue(P('a/b/c.py').full_match('**'))
+        self.assertTrue(P('/a/b/c.py').full_match('**'))
+        self.assertTrue(P('/a/b/c.py').full_match('/**'))
+        self.assertTrue(P('/a/b/c.py').full_match('/a/**'))
+        self.assertTrue(P('/a/b/c.py').full_match('**/*.py'))
+        self.assertTrue(P('/a/b/c.py').full_match('/**/*.py'))
+        self.assertTrue(P('/a/b/c.py').full_match('/a/**/*.py'))
+        self.assertTrue(P('/a/b/c.py').full_match('/a/b/**/*.py'))
+        self.assertTrue(P('/a/b/c.py').full_match('/**/**/**/**/*.py'))
+        self.assertFalse(P('c.py').full_match('**/a.py'))
+        self.assertFalse(P('c.py').full_match('c/**'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a/b'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a/b/c'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a/b/c.'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a/b/c./**'))
+        self.assertFalse(P('a/b/c.py').full_match('**/a/b/c./**'))
+        self.assertFalse(P('a/b/c.py').full_match('/a/b/c.py/**'))
+        self.assertFalse(P('a/b/c.py').full_match('/**/a/b/c.py'))
+        self.assertRaises(ValueError, P('a').full_match, '**a/b/c')
+        self.assertRaises(ValueError, P('a').full_match, 'a/b/c**')
+        # Case-sensitive flag
+        self.assertFalse(P('A.py').full_match('a.PY', case_sensitive=True))
+        self.assertTrue(P('A.py').full_match('a.PY', case_sensitive=False))
+        self.assertFalse(P('c:/a/B.Py').full_match('C:/A/*.pY', case_sensitive=True))
+        self.assertTrue(P('/a/b/c.py').full_match('/A/*/*.Py', case_sensitive=False))
+        # Matching against empty path
+        self.assertFalse(P('').full_match('*'))
+        self.assertTrue(P('').full_match('**'))
+        self.assertFalse(P('').full_match('**/*'))
+        # Matching with empty pattern
+        self.assertTrue(P('').full_match(''))
+        self.assertTrue(P('.').full_match('.'))
+        self.assertFalse(P('/').full_match(''))
+        self.assertFalse(P('/').full_match('.'))
+        self.assertFalse(P('foo').full_match(''))
+        self.assertFalse(P('foo').full_match('.'))
+
     def test_parts_common(self):
         # `parts` returns a tuple.
         sep = self.sep