Use core::ptr::fn_addr_eq for function pointer comparisons - #8430

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

_{Comment @coderabbitai help to get the list of available commands.}

📦 Library Dependencies

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

[x] lib: cpython/Lib/ssl.py
[x] test: cpython/Lib/test/test_ssl.py (TODO: 10)

dependencies:

• ssl

dependent tests: (53 tests)

• ssl: test_asyncio test_ftplib test_httplib test_httpservers test_imaplib test_logging test_poplib test_ssl test_urllib test_urllib2_localnet test_venv test_xmlrpc
  • asyncio.selector_events: test_asyncio
  • ftplib: test_urllib2
    • urllib.request: test_http_cookiejar test_pathlib test_pydoc test_sax test_site test_urllib2net test_urllibnet
  • http.client: test_docxmlrpc test_hashlib test_ucn test_unicodedata test_wsgiref
    • logging.handlers: test_concurrent_futures test_pkgutil
  • http.server: test_robotparser
    • pydoc: test_enum
  • smtplib: test_smtplib test_smtpnet
  • urllib.request:
    • pathlib: test_ast test_dbm_sqlite3 test_ensurepip test_importlib test_json test_launcher test_pathlib test_peg_generator test_pyrepl test_runpy test_tarfile test_tempfile test_tomllib test_tools test_traceback test_unparse test_winapi test_zipapp test_zipfile test_zoneinfo test_zstd

[x] lib: cpython/Lib/asyncio
[ ] test: cpython/Lib/test/test_asyncio (TODO: 31)

dependencies:

• asyncio

dependent tests: (7 tests)

• asyncio: test_asyncio test_external_inspection test_inspect test_logging test_os test_pdb test_unittest

Legend:

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• [x] up-to-date, [ ] outdated

While trying #8422, I noticed that this code compares function pointers by casting them to integers, so I tried replacing it with std::ptr::fn_addr_eq.

However, while this avoids the integer cast, the Miri job still reports UB when comparing this function pointer, so it doesn’t actually improve the current situation.

Since this change doesn’t resolve the underlying issue, I’m closing this PR for now. It can be revisited if a Miri-compatible approach is found.