AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

How CPython handles metaclass= in class statements

This walks through the full lifecycle of a metaclass= keyword argument, from the bytecode the compiler emits for a class statement down to the metaclass resolution logic in builtins.__build_class__ and _PyType_CalculateMetaclass. All permalinks pin to commit d931725bc850cd096f6703bc285e885f1e015f05.

1. The compiler lowers class to a call to __build_class__

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}

AlexWaygood

{"version": 1, "file_mapping": {"main.py": "main.py", "pyproject.toml": "pyproject.toml"}}