Make `warnings.catch_warnings()` use a context variable for holding the warning filtering state if the `sys.flags.context_aware_warnings` flag is set to true. This makes using the context manager thread-safe in multi-threaded programs. Add the `sys.flags.thread_inherit_context` flag. If true, starting a new thread with `threading.Thread` will use a copy of the context from the caller of `Thread.start()`. Both these flags are set to true by default for the free-threaded build and false for the default build. Move the Python implementation of warnings.py into _py_warnings.py. Make _contextvars a builtin module. Co-authored-by: Kumar Aditya <kumaraditya@python.org>
The Python C API ================ The C API is divided into these sections: 1. ``Include/``: Limited API 2. ``Include/cpython/``: CPython implementation details 3. ``Include/cpython/``, names with the ``PyUnstable_`` prefix: API that can change between minor releases 4. ``Include/internal/``, and any name with ``_`` prefix: The internal API Information on changing the C API is available `in the developer guide`_ .. _in the developer guide: https://devguide.python.org/c-api/