Norm path before compare

news/11719.bugfix.rst

@@ -0,0 +1 @@
+Normalize paths before checking if installed scripts are on PATH.

src/pip/_internal/operations/install/wheel.py

@@ -143,16 +143,18 @@ def message_about_scripts_not_on_PATH(scripts: Sequence[str]) -> Optional[str]:
 
     # We don't want to warn for directories that are on PATH.
     not_warn_dirs = [
-        os.path.normcase(i).rstrip(os.sep)
+        os.path.normcase(os.path.normpath(i)).rstrip(os.sep)
         for i in os.environ.get("PATH", "").split(os.pathsep)
     ]
     # If an executable sits with sys.executable, we don't warn for it.
     #     This covers the case of venv invocations without activating the venv.
-    not_warn_dirs.append(os.path.normcase(os.path.dirname(sys.executable)))
+    not_warn_dirs.append(
+        os.path.normcase(os.path.normpath(os.path.dirname(sys.executable)))
+    )
     warn_for: Dict[str, Set[str]] = {
         parent_dir: scripts
         for parent_dir, scripts in grouped_by_dir.items()
-        if os.path.normcase(parent_dir) not in not_warn_dirs
+        if os.path.normcase(os.path.normpath(parent_dir)) not in not_warn_dirs
     }
     if not warn_for:
         return None

tests/unit/test_wheel.py

@@ -589,6 +589,12 @@ def test_multi_script__single_dir_on_PATH(self) -> None:
         )
         assert retval is None
 
+    def test_PATH_check_path_normalization(self) -> None:
+        retval = self._template(
+            paths=["/a/./b/../b//c/", "/d/e/bin"], scripts=["/a/b/c/foo"]
+        )
+        assert retval is None
+
     def test_single_script__single_dir_on_PATH(self) -> None:
         retval = self._template(paths=["/a/b", "/c/d/bin"], scripts=["/a/b/foo"])
         assert retval is None