Beispiel

six lazy moved descriptors cache resolved targets directly onto instance dictionaries while deleting themselves from parent class dictionaries, causing class-level lookups to fail and leaving sys.meta_path importers decoupled from remove_move and add_move

sha256:b632b8e946a5c728dc7d1654280ec14c45ffffd3c37cf0d43ddaa4ece84a11da

Fall

Ziel

six lazy moved descriptors cache resolved targets directly onto instance dictionaries while deleting themselves from parent class dictionaries, causing class-level lookups to fail and leaving sys.meta_path importers decoupled from remove_move and add_move HOW

Pakete

six 1.17.0

Umgebung

python

Erstellt

2026-08-17T07:05:16Z

Häufige Annahme

Accessing moved attributes on six.moves or its classes returns the descriptor or resolved object identically without mutating class state, and six.remove_move cleans up import hooks alongside attribute access

So hat der Autor des Samples festgehalten, was eine Entwicklerin oder ein Modell hier erwarten würde. Der Vertrag darunter ist das, was tatsächlich lief.

Contract

• Accessing an attribute on six.moves or its lazy namespaces resolves the target, caches it in the instance dictionary, and deletes the lazy descriptor from the class dictionary, making class-level attribute access fail with AttributeError
• Accessing unresolved lazy descriptors directly on six._MovedItems raises AttributeError because _LazyDescr attempts setattr on None instead of returning self
• six.remove_move purges moves from _MovedItems and six.moves instance dictionaries while leaving six._importer.known_modules intact, allowing subsequent import statements to re-resolve the removed module
• six.add_move registers descriptors on _MovedItems for attribute lookup but does not update six._importer.known_modules, causing direct import statements for added moves to raise ModuleNotFoundError
• Direct attribute lookup on MovedModule instances resolves the underlying module and caches the attribute on the descriptor instance via __getattr__
• six.reraise clears its local value and traceback references in a finally block to prevent circular reference cycles between execution frames and traceback objects

Dateien

• NOTES.md
• csx.json
• requirements.txt
• test/__init__.py
• test/contract.py

Quellartefakt herunterladen (tar.gz)

Ursprungs-Seeder

csx-seed

Verifizierungsbelege

• python 3.12 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-17 · ed25519:d91480838ac982c9