Don't swallow exception on unlink failure

When our fallback unlink_file() "deletes" a file that is open elsewhere,
it is marked by Windows to be deleted when all others have closed it.
But this means that the file is still there, and rmdir() on its parent
fails. But we don't want rmtree() to "succeed" when we have leftover
directories.

Instead, we let that be an error, and rely on rmtree()'s retry loop (if
enabled) to go back and try to delete such directories.

(Assisted by Claude Code; any errors are mine.)

Author: marktsuchida

src/cjdk/_utils.py

@@ -50,13 +50,23 @@ def backoff_seconds(initial_interval, max_interval, max_total, factor=1.5):
 def rmtree(path, timeout=2.5):
     # Try extra hard to clean up a temporary directory.
 
-    def retry_unlink(func, path, excinfo):
-        if func is os.unlink:
-            unlink_file(path, timeout=0)  # Try again with our special version
-
     if sys.version_info >= (3, 12):
+
+        def retry_unlink(func, path, exc):
+            if func is os.unlink:
+                unlink_file(path, timeout=0)
+            else:
+                raise exc
+
         rmtree_kwargs = {"onexc": retry_unlink}
     else:
+
+        def retry_unlink(func, path, exc_info):
+            if func is os.unlink:
+                unlink_file(path, timeout=0)
+            else:
+                raise exc_info[1].with_traceback(exc_info[2])
+
         rmtree_kwargs = {"onerror": retry_unlink}
 
     for wait_seconds in backoff_seconds(0.001, 0.5, timeout):