Do not collect symlinked tests under Windows (#12050)

The check for short paths under Windows via os.path.samefile, introduced in #11936, also found similar tests in symlinked tests in the GH Actions CI.

Fixes #12039.

Co-authored-by: Bruno Oliveira <[email protected]>

Author: mrbean-bremen

Diff for: AUTHORS

@@ -283,6 +283,7 @@ Mike Hoyle (hoylemd)
 Mike Lundy
 Milan Lesnek
 Miro Hrončok
+mrbean-bremen
 Nathaniel Compton
 Nathaniel Waisbrot
 Ned Batchelder

Diff for: changelog/12039.bugfix.rst

@@ -0,0 +1 @@
+Fixed a regression in ``8.0.2`` where tests created using :fixture:`tmp_path` have been collected multiple times in CI under Windows.

Diff for: src/_pytest/main.py

@@ -924,7 +924,14 @@ def collect(self) -> Iterator[Union[nodes.Item, nodes.Collector]]:
                         if sys.platform == "win32" and not is_match:
                             # In case the file paths do not match, fallback to samefile() to
                             # account for short-paths on Windows (#11895).
-                            is_match = os.path.samefile(node.path, matchparts[0])
+                            same_file = os.path.samefile(node.path, matchparts[0])
+                            # We don't want to match links to the current node,
+                            # otherwise we would match the same file more than once (#12039).
+                            is_match = same_file and (
+                                os.path.islink(node.path)
+                                == os.path.islink(matchparts[0])
+                            )
+
                     # Name part e.g. `TestIt` in `/a/b/test_file.py::TestIt::test_it`.
                     else:
                         # TODO: Remove parametrized workaround once collection structure contains

Diff for: testing/test_collection.py

@@ -1765,7 +1765,7 @@ def test_foo(): assert True
 
 @pytest.mark.skipif(not sys.platform.startswith("win"), reason="Windows only")
 def test_collect_short_file_windows(pytester: Pytester) -> None:
-    """Reproducer for #11895: short paths not colleced on Windows."""
+    """Reproducer for #11895: short paths not collected on Windows."""
     short_path = tempfile.mkdtemp()
     if "~" not in short_path:  # pragma: no cover
         if running_on_ci():
@@ -1832,3 +1832,28 @@ def test_pyargs_collection_tree(pytester: Pytester, monkeypatch: MonkeyPatch) ->
         ],
         consecutive=True,
     )
+
+
+def test_do_not_collect_symlink_siblings(
+    pytester: Pytester, tmp_path: Path, request: pytest.FixtureRequest
+) -> None:
+    """
+    Regression test for #12039: Do not collect from directories that are symlinks to other directories in the same path.
+
+    The check for short paths under Windows via os.path.samefile, introduced in #11936, also finds the symlinked
+    directory created by tmp_path/tmpdir.
+    """
+    # Use tmp_path because it creates a symlink with the name "current" next to the directory it creates.
+    symlink_path = tmp_path.parent / (tmp_path.name[:-1] + "current")
+    assert symlink_path.is_symlink() is True
+
+    # Create test file.
+    tmp_path.joinpath("test_foo.py").write_text("def test(): pass", encoding="UTF-8")
+
+    # Ensure we collect it only once if we pass the tmp_path.
+    result = pytester.runpytest(tmp_path, "-sv")
+    result.assert_outcomes(passed=1)
+
+    # Ensure we collect it only once if we pass the symlinked directory.
+    result = pytester.runpytest(symlink_path, "-sv")
+    result.assert_outcomes(passed=1)