Fix PurePosixPath.joinpath under Windows

- fixes #1070

Author: mrbean-bremen

CHANGES.md

@@ -29,6 +29,8 @@ The released versions correspond to PyPI releases.
   (see [#1053](../../issues/1053))
 * `PurePosixPath` reported Windows reserved names as reserved in Python >= 3.12
   (see [#1067](../../issues/1067))
+* `PurePosixPath.joinpath()` incorrectly handled paths with drives under Windows in Python >= 3.12
+  (see [#1070](../../issues/1070))
 
 ## [Version 5.6.0](https://pypi.python.org/pypi/pyfakefs/5.6.0) (2024-07-12)
 Adds preliminary Python 3.13 support.

pyfakefs/fake_filesystem.py

@@ -1306,18 +1306,17 @@ def joinpaths(self, *paths: AnyStr) -> AnyStr:
             return paths[0]
         if self.is_windows_fs:
             return self._join_paths_with_drive_support(*file_paths)
-        joined_path_segments = []
+        path = file_paths[0]
         sep = self.get_path_separator(file_paths[0])
-        for path_segment in file_paths:
-            if self._starts_with_root_path(path_segment):
+        for path_segment in file_paths[1:]:
+            if path_segment.startswith(sep) or not path:
                 # An absolute path
-                joined_path_segments = [path_segment]
+                path = path_segment
+            elif path.endswith(sep):
+                path += path_segment
             else:
-                if joined_path_segments and not joined_path_segments[-1].endswith(sep):
-                    joined_path_segments.append(sep)
-                if path_segment:
-                    joined_path_segments.append(path_segment)
-        return matching_string(file_paths[0], "").join(joined_path_segments)
+                path += sep + path_segment
+        return path
 
     @overload
     def _path_components(self, path: str) -> List[str]: ...

pyfakefs/tests/fake_pathlib_test.py

@@ -328,13 +328,10 @@ def test_joinpath(self):
         self.assertEqual(
             self.path("/foo").joinpath("bar", "baz"), self.path("/foo/bar/baz")
         )
-        if os.name != "nt":
-            # under Windows, this does not work correctly at the moment
-            # we get "C:/Program Files" instead
-            self.assertEqual(
-                self.path("c:").joinpath("/Program Files"),
-                self.path("/Program Files"),
-            )
+        self.assertEqual(
+            self.path("c:").joinpath("/Program Files"),
+            self.path("/Program Files"),
+        )
 
     def test_match(self):
         self.assertTrue(self.path("a/b.py").match("*.py"))