fix reloader path split and join on Windows

2 files changed, 4 insertions, 3 deletions

diff --git a/src/werkzeug/_reloader.py b/src/werkzeug/_reloader.py
index c3a7b098..98a3fd67 100644
--- a/src/werkzeug/_reloader.py
+++ b/src/werkzeug/_reloader.py
@@ -6,6 +6,7 @@ import threading
 import time
 import typing as t
 from itertools import chain
+from pathlib import PurePath
 
 from ._internal import _log
 
@@ -112,7 +113,7 @@ def _find_watchdog_paths(extra_files, exclude_patterns):
 def _find_common_roots(paths):
     root = {}
 
-    for chunks in sorted((x.split(os.path.sep) for x in paths), key=len, reverse=True):
+    for chunks in sorted((PurePath(x).parts for x in paths), key=len, reverse=True):
         node = root
 
         for chunk in chunks:
@@ -127,7 +128,7 @@ def _find_common_roots(paths):
             _walk(child, path + (prefix,))
 
         if not node:
-            rv.add("/".join(path))
+            rv.add(os.path.join(*path))
 
     _walk(root, ())
     return rv
diff --git a/tests/test_serving.py b/tests/test_serving.py
index 8be75a45..ecfa127b 100644
--- a/tests/test_serving.py
+++ b/tests/test_serving.py
@@ -113,7 +113,7 @@ def test_exclude_patterns(find):
     paths = find(set(), set())
     assert any(p.startswith(sys.prefix) for p in paths)
     # Those paths should be excluded due to the pattern.
-    paths = find(set(), {f"{sys.prefix}/*"})
+    paths = find(set(), {f"{sys.prefix}*"})
     assert not any(p.startswith(sys.prefix) for p in paths)