Stubgen: normalize input paths when finding common parent directory for out files (#8067)

Signed-off-by: Oleg Höfling <[email protected]>

Author: hoefling

mypy/stubutil.py

@@ -247,11 +247,11 @@ def remove_misplaced_type_comments(source: Union[str, bytes]) -> Union[str, byte
 def common_dir_prefix(paths: List[str]) -> str:
     if not paths:
         return '.'
-    cur = os.path.dirname(paths[0])
+    cur = os.path.dirname(os.path.normpath(paths[0]))
     for path in paths[1:]:
         while True:
-            path = os.path.dirname(path)
-            if (cur + '/').startswith(path + '/'):
+            path = os.path.dirname(os.path.normpath(path))
+            if (cur + os.sep).startswith(path + os.sep):
                 cur = path
                 break
     return cur or '.'

mypy/test/teststubgen.py

@@ -445,7 +445,9 @@ def h():
 
         assert_equal(remove_misplaced_type_comments(original), dest)
 
-    def test_common_dir_prefix(self) -> None:
+    @unittest.skipIf(sys.platform == 'win32',
+                     'Tests building the paths common ancestor on *nix')
+    def test_common_dir_prefix_unix(self) -> None:
         assert common_dir_prefix([]) == '.'
         assert common_dir_prefix(['x.pyi']) == '.'
         assert common_dir_prefix(['./x.pyi']) == '.'
@@ -458,6 +460,26 @@ def test_common_dir_prefix(self) -> None:
         assert common_dir_prefix(['foo/x.pyi', 'foo/bar/zar/y.pyi']) == 'foo'
         assert common_dir_prefix(['foo/bar/zar/x.pyi', 'foo/bar/y.pyi']) == 'foo/bar'
         assert common_dir_prefix(['foo/bar/x.pyi', 'foo/bar/zar/y.pyi']) == 'foo/bar'
+        assert common_dir_prefix([r'foo/bar\x.pyi']) == 'foo'
+        assert common_dir_prefix([r'foo\bar/x.pyi']) == r'foo\bar'
+
+    @unittest.skipIf(sys.platform != 'win32',
+                     'Tests building the paths common ancestor on Windows')
+    def test_common_dir_prefix_win(self) -> None:
+        assert common_dir_prefix(['x.pyi']) == '.'
+        assert common_dir_prefix([r'.\x.pyi']) == '.'
+        assert common_dir_prefix([r'foo\bar\x.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo\bar\x.pyi',
+                                  r'foo\bar\y.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo\bar\x.pyi', r'foo\y.pyi']) == 'foo'
+        assert common_dir_prefix([r'foo\x.pyi', r'foo\bar\y.pyi']) == 'foo'
+        assert common_dir_prefix([r'foo\bar\zar\x.pyi', r'foo\y.pyi']) == 'foo'
+        assert common_dir_prefix([r'foo\x.pyi', r'foo\bar\zar\y.pyi']) == 'foo'
+        assert common_dir_prefix([r'foo\bar\zar\x.pyi', r'foo\bar\y.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo\bar\x.pyi', r'foo\bar\zar\y.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo/bar\x.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo\bar/x.pyi']) == r'foo\bar'
+        assert common_dir_prefix([r'foo/bar/x.pyi']) == r'foo\bar'
 
 
 class StubgenHelpersSuite(unittest.TestCase):