Issues

• pystats asserts on valid register-cached uop IDs

  interpreter-coretopic-JITtype-bug
  python/cpython#159511 · Filter by author cocolato opened on Oct 16, 2026

• asyncio: large bytes write is quadratic when queued behind pending data

  type-bug
  python/cpython#159503 · Filter by author Ar-maan05 opened on Oct 16, 2026

• Improve performance of asyncio StreamReader .readline() and .readuntil()

  performancetopic-asynciotype-feature
  python/cpython#159500 · Filter by author cmaloney opened on Oct 16, 2026

• PowerShell venv activation treats square brackets in paths as wildcards

  OS-windowsstdlibtopic-venvtype-bug
  python/cpython#159498 · Filter by author repzakske opened on Oct 15, 2026

• Running test test_read1_error_does_not_cause_reentrant_failure triggers ASan allocation error in test_bufferedio

  type-crash
  python/cpython#159497 · Filter by author ChaseKnowlden opened on Oct 15, 2026

• No embeddable or test packages publishing for free-threading on Windows

  3.143.153.16OS-windowstopic-installation
  python/cpython#159494 · Filter by author zooba opened on Oct 15, 2026

• free-threading one line comprehension is significantly slower than multi line

  interpreter-coreperformancetopic-free-threadingtopic-parsertype-bug
  python/cpython#159493 · Filter by author johng opened on Oct 15, 2026
  1

• Nested lock in set.issuperset

  interpreter-coreperformancetopic-free-threadingtype-feature
  python/cpython#159486 · Filter by author johng opened on Oct 15, 2026

• Interpreter shutdown can deadlock when a daemon thread holds the warnings lock

  3.143.153.16interpreter-coretype-bug
  python/cpython#159485 · Filter by author ngoldbaum opened on Oct 15, 2026
  

• email.utils.parseaddr(strict=True) silently splices inline comments in the local-part

  stdlibtopic-emailtype-bug
  python/cpython#159475 · Filter by author D3e4mlike opened on Oct 15, 2026

• Improve incomplete input detection

  interpreter-coretopic-parsertype-bug
  python/cpython#159465 · Filter by author pablogsal opened on Oct 15, 2026

• Use C23/C++17 attributes

  topic-C-APItype-feature
  python/cpython#159464 · Filter by author encukou opened on Oct 15, 2026
  

• 3.16.0a1 freethreading-debug build on i686: test_destroy_subinterpreter_does_not_abort triggers assertion in mimalloc

  interpreter-coretopic-free-threadingtype-bug
  python/cpython#159462 · Filter by author befeleme opened on Oct 15, 2026

• _pyrepl: AssertionError in pos2xy when recalling long multi-line wide-character history

  pendingstdlibtopic-repltype-bug
  python/cpython#159459 · Filter by author nsyhykui opened on Oct 15, 2026
  6

• Free-threading: data race on static cache in _datetime.normalize_century()

  extension-modulestype-bug
  python/cpython#159458 · Filter by author AnnaAr321 opened on Oct 15, 2026
  2

• When performing the build of MSVC or MinGW .pyd, abi3t throws an error...... There is a conflict in the macro definition

  pendingtype-bug
  python/cpython#159457 · Filter by author Xiaozhi-Python-Road opened on Oct 15, 2026
  2

• Tools/build/regen-configure.sh leaves a root-owned autom4te.cache, breaking later autoconf runs in the same tree

  buildtype-bug
  python/cpython#159452 · Filter by author sendaoYan opened on Oct 15, 2026

• AsyncIO thread-safety issue in Python 3.14's free-threading

  stdlibtopic-asynciotopic-free-threadingtype-bug
  python/cpython#159449 · Filter by author jblespiau opened on Oct 15, 2026
  2

• Reduce unnecessary work in FileIO

  extension-modulesperformancetopic-IOtype-refactor
  python/cpython#159446 · Filter by author cmaloney opened on Oct 15, 2026
  

• Avoid redundant garbage collector traversals

  3.16interpreter-coreperformancetype-feature
  python/cpython#159437 · Filter by author mfalco-oai opened on Oct 14, 2026
  3

  

• tarfile: a pax size record followed by a GNU long-name header makes tarfile duplicate, invent or skip members

  stdlibtype-bug
  python/cpython#159435 · Filter by author gpshead opened on Oct 14, 2026
  1

• Function __annotations__ can cache a stale result from __annotate__

  interpreter-coretype-bug
  python/cpython#159434 · Filter by author nascheme opened on Oct 14, 2026
  1

• _PyObject_XDecRefDelayed() should handle immortal objects

  interpreter-coretopic-free-threadingtype-bug
  python/cpython#159431 · Filter by author nascheme opened on Oct 14, 2026

• Some missing error checks on _PyObject_LookupSpecial in bytes and weakref

  interpreter-coretype-bug
  python/cpython#159430 · Filter by author msullivan opened on Oct 14, 2026

• Don't load from mimetypes.knownfiles by default on Windows

  stdlibtype-bugtype-security
  python/cpython#159428 · Filter by author sethmlarson opened on Oct 14, 2026