Issues

• Use vsnprintf() on all platforms in PyOS_vsnprintf()

  interpreter-coreOS-windowstopic-C-APItype-bug
  python/cpython#162054 · Filter by author deronnax opened on Nov 15, 2026

• free threading stop_the_world can be slow to complete

  interpreter-coreperformancetopic-free-threadingtype-feature
  python/cpython#162052 · Filter by author johng opened on Nov 15, 2026

• [C API] Add PyFrozenDict_New() to the limited C API 3.16

  topic-C-APItype-feature
  python/cpython#162047 · Filter by author vstinner opened on Nov 15, 2026
  

• Confusing SyntaxError when using {**_} inside PM's mapping pattern

  interpreter-coretopic-parsertype-bug
  python/cpython#162045 · Filter by author sobolevn opened on Nov 15, 2026
  

• Apple testbed fails to build when its path contains a space

  buildOS-iostype-bug
  python/cpython#162034 · Filter by author fametrano opened on Nov 15, 2026

• BufferedIOBase.readinto raises TypeError when called on a non-blocking streams block with no data

  topic-IOtype-bug
  python/cpython#162031 · Filter by author cmaloney opened on Nov 15, 2026
  

• Pure Python JSON decoder reports the error position one character past an invalid escape

  stdlibtype-bug
  python/cpython#162028 · Filter by author thejesh23 opened on Nov 15, 2026

• sys.monitoring: wrong branch events for async comprehensions and for a second async for loop

  interpreter-coretopic-asynciotype-bug
  python/cpython#162027 · Filter by author 0z5a opened on Nov 14, 2026
  1

• macOS pipe writable notification can leave subprocess.communicate() blocked past timeout

  OS-mactype-bug
  python/cpython#162016 · Filter by author hakula139 opened on Nov 14, 2026
  1

• imaplib: a rejected APPEND leaves its message pending as the literal of the next command

  stdlibtopic-emailtype-security
  python/cpython#162010 · Filter by author omercnet opened on Nov 14, 2026
  1

• Free-threaded: per-thread refcount arrays cost 8 bytes x unique-id pool size of RSS in every thread

  topic-free-threadingtype-bug
  python/cpython#161998 · Filter by author aryanj723 opened on Nov 14, 2026
  3

• Segfault in Interpreter.exec() when the uncaught exception's __str__ raises

  extension-modulestopic-subprocesstype-crash
  python/cpython#161996 · Filter by author aisk opened on Nov 14, 2026

• textwrap: wrapping a long word takes quadratic time

  performancestdlibtype-feature
  python/cpython#161977 · Filter by author thejesh23 opened on Nov 14, 2026

• SequenceMatcher.get_grouped_opcodes() changes the result of later get_opcodes() calls

  stdlibtype-bug
  python/cpython#161973 · Filter by author Broyojo opened on Nov 14, 2026
  3

• cmath.log(0, base) returns (-inf+nanj) instead of raising ValueError

  extension-modulestype-bug
  python/cpython#161972 · Filter by author Broyojo opened on Nov 14, 2026
  4

• collections.UserString.replace() rejects the count keyword

  stdlibtype-bug
  python/cpython#161970 · Filter by author Broyojo opened on Nov 14, 2026

• email: UnboundLocalError parsing a Message-ID whose domain literal starts with whitespace

  stdlibtopic-emailtype-bug
  python/cpython#161966 · Filter by author Broyojo opened on Nov 14, 2026

• importlib.util.LazyLoader deadlocks when two threads first-touch modules in an import cycle

  stdlibtopic-importlibtype-bug
  python/cpython#161962 · Filter by author djrobstep opened on Nov 13, 2026

• [Security] Memory Exhaustion (OOM) and Resource Leak via crafted PAX Headers in tarfile

  stdlibtype-bug
  python/cpython#161955 · Filter by author 1x98 opened on Nov 13, 2026
  3

• zipfile honors inconsistent compression method state when extracting

  stdlibtype-bug
  python/cpython#161945 · Filter by author woodruffw opened on Nov 13, 2026
  1

• Freeze encodings module during startup

  interpreter-coreperformancetype-feature
  python/cpython#161941 · Filter by author eendebakpt opened on Nov 13, 2026

• Make print() use a single write() call

  interpreter-coretopic-IOtype-feature
  python/cpython#161934 · Filter by author methane opened on Nov 13, 2026

• ProcessPoolExecutor: a worker spawned on demand by submit() can die unnoticed (no BrokenProcessPool, hang) with forkserver/spawn

  stdlibtopic-multiprocessingtype-bug
  python/cpython#161931 · Filter by author atrotter01 opened on Nov 13, 2026

• sys.monitoring: async for emits BRANCH_RIGHT when __anext__ raises an exception other than StopAsyncIteration

  interpreter-coretype-bug
  python/cpython#161928 · Filter by author KRRT7 opened on Nov 13, 2026
  1

• complex(x) ignores an overridden __float__ of a float subclass since 3.14

  3.143.153.16interpreter-coretype-bug
  python/cpython#161926 · Filter by author jseop-lim opened on Nov 13, 2026
  1