Fixed a crash if the stack limit was too low

- we need to pass the wanted stack limit

Author: mrbean-bremen

CHANGES.md

@@ -2,6 +2,12 @@
 The released versions correspond to PyPI releases.
 `pyfakefs` versions follow [Semantic Versioning](https://semver.org/).
 
+## Unreleased
+
+### Fixes
+* fixed a crash if the stack limit was set to a low value
+  (see [#1313](https://github.com/pytest-dev/pyfakefs/issues/1313))
+
 ## [Version 6.2.0](https://pypi.python.org/pypi/pyfakefs/6.2.0) (2026-04-12)
 Changes the MRO for file wrappers.
 

pyfakefs/helpers.py

@@ -511,7 +511,7 @@ def starts_with(path, string):
     if not skip_names and not check_open_code:
         return False
 
-    stack = traceback.extract_stack()
+    stack = traceback.extract_stack(limit=6)
 
     # handle the case that we try to call the original `open_code`
     # (since Python 3.12)

pyfakefs/tests/fake_open_test.py

@@ -1063,6 +1063,19 @@ def test_file_class(self):
             assert isinstance(f, io.BufferedIOBase)
             assert f.read() == b"test"
 
+    def test_stacklimit(self):
+        """Regression test for #1313 - handle reduced stack limit"""
+        old_tracebacklimit = (
+            sys.tracebacklimit if hasattr(sys, "tracebacklimit") else None
+        )
+        sys.tracebacklimit = 2
+        try:
+            file_path = self.make_path("foo")
+            with self.open(file_path, "w") as f:
+                f.write("test")
+        finally:
+            sys.tracebacklimit = old_tracebacklimit
+
 
 class RealFileOpenTest(FakeFileOpenTest):
     def use_real_fs(self):