From 411751e7aafd882a2612bf4673e7a29008b1da81 Mon Sep 17 00:00:00 2001
From: Frank Hoffmann <15r10nk-git@polarbit.de>
Date: Tue, 8 Sep 2026 08:06:28 +0200
Subject: [PATCH] fix: bytecode cache invalidation for moved test files
 (#14552)

---
 changelog/14552.bugfix.rst       |  1 +
 src/_pytest/assertion/rewrite.py |  7 +++++++
 testing/test_assertrewrite.py    | 25 +++++++++++++++++++++++++
 3 files changed, 33 insertions(+)
 create mode 100644 changelog/14552.bugfix.rst

diff --git a/changelog/14552.bugfix.rst b/changelog/14552.bugfix.rst
new file mode 100644
index 00000000000..8e8f01d9d19
--- /dev/null
+++ b/changelog/14552.bugfix.rst
@@ -0,0 +1 @@
+Fixed assertion-rewrite cache invalidation for moved test files: a rewritten ``.pyc`` whose ``co_filename`` no longer matches the current source path is now treated as stale and rewritten. Previously, renaming or moving a test module/directory could leak the old path into ``inspect.currentframe().f_code.co_filename`` and related traceback/reporting paths.
diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 27953336c5c..1709c6c4b5e 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -379,6 +379,13 @@ def _read_pyc(
         if not isinstance(co, types.CodeType):
             trace(f"_read_pyc({source}): not a code object")
             return None
+        # A cached pyc can be moved together with the source file (for example
+        # by renaming a package or test directory). In that case the marshaled
+        # code object's ``co_filename`` still points to the old source path.
+        # Treat that as stale so the caller rewrites and recreates the cache.
+        if co.co_filename != str(source):
+            trace(f"_read_pyc({source}): stale filename {co.co_filename!r}")
+            return None
         return co
 
 
diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index c9736f8fa48..98e7b54589e 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -1161,6 +1161,31 @@ def test_foo():
             glob.glob("__pycache__/*.pyc")
         )
 
+    def test_moved_test_file_updates_code_filename(
+        self, pytester: Pytester, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        """Moving a test module must keep ``co_filename`` synchronized with ``__file__``."""
+        monkeypatch.delenv("PYTHONPYCACHEPREFIX", raising=False)
+
+        pytester.makepyfile(
+            **{
+                "test1/test_a.py": """
+                from inspect import currentframe
+
+                def test_a():
+                    assert currentframe().f_code.co_filename == __file__
+                """
+            }
+        )
+
+        first = pytester.runpytest_subprocess("-s", "test1/test_a.py")
+        first.assert_outcomes(passed=1)
+
+        pytester.path.joinpath("test1").rename(pytester.path.joinpath("test2"))
+
+        second = pytester.runpytest_subprocess("-s", "test2/test_a.py")
+        second.assert_outcomes(passed=1)
+
     @pytest.mark.skipif('"__pypy__" in sys.modules')
     def test_pyc_vs_pyo(
         self,