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sequenceDiagram
    participant Parent as Parent Process
    participant Fork as Fork Operation
    participant Child as Child Process
    participant Locks as VM State Locks
    participant Cleanup as Cleanup Handler

    Parent->>Fork: Call fork()
    Fork->>Child: Create child, copy memory/locks
    Fork-->>Parent: Return to parent
    
    Child->>Cleanup: Begin child initialization
    Cleanup->>Locks: Check if write lock available (try_lock)
    alt Lock held by dead thread
        Cleanup->>Locks: force_unlock_after_fork()
        Locks->>Locks: Repeatedly unlock read locks
        Locks->>Locks: Or force unlock write lock
        Locks->>Locks: Acquire clean write lock
    else Lock available
        Locks-->>Cleanup: Write lock acquired
    end
    
    Cleanup->>Locks: Unlock and proceed
    Cleanup->>Child: Resume child execution

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Code has been automatically formatted

The code in this PR has been formatted using:

• cargo fmt --all
  Please pull the latest changes before pushing again:

git pull origin after-fork

📦 Library Dependencies

The following Lib/ modules were modified. Here are their dependencies:

[ ] lib: cpython/Lib/ctypes
[ ] test: cpython/Lib/test/test_ctypes (TODO: 17)
[x] test: cpython/Lib/test/test_stable_abi_ctypes.py

dependencies:

• ctypes (native: _ctypes, ctypes._endian, ctypes.macholib.dylib, ctypes.macholib.framework, itertools, sys)
  • subprocess (native: builtins, errno, sys, time)
  • sysconfig (native: os.path, sys)
  • types
  • os, re, shutil, struct, warnings

dependent tests: (1 tests)

• ctypes: test_ctypes

[x] lib: cpython/Lib/inspect.py
[ ] test: cpython/Lib/test/test_inspect (TODO: 48)

dependencies:

• inspect

dependent tests: (45 tests)

• inspect: test_abc test_argparse test_asyncgen test_buffer test_builtin test_code test_collections test_coroutines test_decimal test_enum test_functools test_generators test_grammar test_inspect test_ntpath test_operator test_patma test_posixpath test_pydoc test_signal test_traceback test_type_annotations test_types test_typing test_unittest test_yield_from test_zipimport
  • asyncio: test_asyncio test_contextlib_async test_logging test_os test_sys_settrace test_unittest
  • bdb: test_bdb
  • dataclasses: test__colorize test_ctypes test_genericalias test_pprint test_regrtest test_zoneinfo
  • importlib.metadata: test_importlib
  • pydoc:
    • xmlrpc.server: test_docxmlrpc test_xmlrpc
  • rlcompleter: test_rlcompleter
  • trace: test_trace

[ ] lib: cpython/Lib/multiprocessing
[ ] test: cpython/Lib/test/test_multiprocessing_fork (TODO: 35)
[ ] test: cpython/Lib/test/test_multiprocessing_forkserver (TODO: 10)
[ ] test: cpython/Lib/test/test_multiprocessing_spawn (TODO: 13)
[x] test: cpython/Lib/test/test_multiprocessing_main_handling.py

dependencies:

• multiprocessing (native: _multiprocessing, _winapi, array, atexit, collections.abc, errno, itertools, mmap, msvcrt, sys, time)
  • collections (native: _weakref, itertools, sys)
  • json (native: json.tool, sys)
  • pickle (native: itertools, sys)
  • tempfile (native: _thread, errno, sys)
  • ctypes, subprocess, types
  • _weakrefset, abc, base64, bisect, copyreg, functools, io, os, queue, runpy, secrets, selectors, signal, socket, struct, threading, traceback, warnings, weakref

dependent tests: (5 tests)

• multiprocessing: test_asyncio test_concurrent_futures test_fcntl test_multiprocessing_main_handling
  • concurrent.futures.process: test_concurrent_futures

[ ] lib: cpython/Lib/collections
[x] lib: cpython/Lib/_collections_abc.py
[x] test: cpython/Lib/test/test_collections.py (TODO: 3)
[x] test: cpython/Lib/test/test_deque.py (TODO: 3)
[x] test: cpython/Lib/test/test_defaultdict.py (TODO: 1)
[ ] test: cpython/Lib/test/test_ordered_dict.py (TODO: 4)

dependencies:

• collections

dependent tests: (196 tests)

• collections: test_annotationlib test_array test_asyncio test_bisect test_builtin test_c_locale_coercion test_call test_collections test_configparser test_contains test_csv test_ctypes test_defaultdict test_deque test_dict test_dictviews test_enum test_exception_group test_file test_fileinput test_fileio test_functools test_genericalias test_hash test_httpservers test_inspect test_io test_ipaddress test_iter test_iterlen test_json test_ordered_dict test_pathlib test_patma test_pickle test_plistlib test_pprint test_pydoc test_random test_set test_shelve test_sqlite3 test_statistics test_string test_struct test_traceback test_types test_typing test_unittest test_urllib test_userdict test_userlist test_userstring test_weakref test_weakset test_with
  • asyncio: test_asyncio test_contextlib_async test_logging test_os test_sys_settrace test_unittest
  • concurrent.futures._base: test_concurrent_futures
  • dbm.dumb: test_dbm_dumb
  • dbm.sqlite3: test_dbm_sqlite3
  • difflib: test_difflib
  • dis: test__opcode test_ast test_code test_compile test_compiler_assemble test_dis test_dtrace test_fstring test_opcache test_peepholer test_positional_only_arg
    • inspect: test_abc test_argparse test_asyncgen test_buffer test_coroutines test_decimal test_generators test_grammar test_ntpath test_operator test_posixpath test_signal test_type_annotations test_yield_from test_zipimport
    • trace: test_trace
  • http.client: test_docxmlrpc test_hashlib test_ssl test_ucn test_unicodedata test_urllib2 test_wsgiref test_xmlrpc
    • urllib.request: test_http_cookiejar test_site test_urllib2_localnet test_urllib2net test_urllibnet
  • importlib.metadata: test_importlib test_zoneinfo
  • inspect:
    • bdb: test_bdb
    • dataclasses: test__colorize test_ctypes test_regrtest
    • rlcompleter: test_rlcompleter
  • multiprocessing: test_concurrent_futures test_fcntl test_multiprocessing_main_handling
  • pkgutil: test_pkgutil
  • platform: test__locale test__osx_support test_android test_baseexception test_cmath test_ctypes test_math test_mimetypes test_platform test_posix test_socket test_sysconfig test_time test_winreg
  • pprint: test_htmlparser test_sys_setprofile
  • queue: test_concurrent_futures test_dummy_thread test_sched
  • selectors: test_selectors test_subprocess
    • socketserver: test_imaplib test_socketserver
  • shutil: test_bz2 test_compileall test_ctypes test_filecmp test_glob test_importlib test_largefile test_launcher test_py_compile test_reprlib test_shutil test_string_literals test_support test_tempfile test_venv
    • ctypes.util: test_ctypes
    • ensurepip: test_ensurepip
    • tarfile: test_tarfile
    • tempfile: test_bytes test_cmd_line test_contextlib test_doctest test_faulthandler test_importlib test_linecache test_mailbox test_pkg test_runpy test_tabnanny test_termios test_threadedtempfile test_tomllib test_urllib_response test_winconsoleio test_zipapp test_zipfile test_zipfile64 test_zstd
    • webbrowser: test_webbrowser
    • zipfile: test_zipfile
  • tokenize: test_tokenize test_unparse
    • traceback: test_code_module test_dictcomps test_importlib test_listcomps test_pyexpat test_setcomps test_threading test_unittest
  • traceback:
    • py_compile: test_cmd_line_script test_importlib
  • urllib.parse: test_sqlite3 test_urlparse
  • urllib.robotparser: test_robotparser
  • wave: test_wave

Legend:

• [+] path exists in CPython
• [x] up-to-date, [ ] outdated