Clarify in the Authentication keys section that the authkey handshake
covers Listener/Client (addressable endpoints) only, not the anonymous
pipes behind Pipe() and Queue, and that isolation between same-user
processes must be arranged at the OS level.
No public API change. Lift the per-iteration select/read/write loop out of
Popen._communicate (POSIX) into a module-level _communicate_io_posix(), with
small _flush_stdin / _make_input_view / _translate_newlines helpers alongside
it. Popen._communicate calls the helper and persists the returned input
offset for resume-after-timeout.
Retire the private Popen._remaining_time method in favor of module-level
_deadline_remaining; all call sites (POSIX and Windows) updated.
Defensive behavioural deltas: the stdin and stdout/stderr .close() calls in
the I/O loop now swallow BrokenPipeError / OSError, matching __exit__ and the
no-input path; previously these were bare.
Adds test_communicate_timeout_resume_partial_write to cover _input_offset
bookkeeping across TimeoutExpired/resume.
The add_const() function in flowgraph.c uses a linear search over the
consts list to find the index of a constant. After gh-126835 moved
constant folding from the AST optimizer to the CFG optimizer, this
function is now called N times for N inner tuple elements during
fold_tuple_of_constants(), resulting in O(N²) total time.
Fix by maintaining an auxiliary _Py_hashtable_t that maps object
pointers to their indices in the consts list, providing O(1) lookup.
For a file with 100,000 constant 2-tuples:
- Before: 10.38s (add_const occupies 83.76% of CPU time)
- After: 1.48s
gh-141473: Speed up test_communicate_timeout_large_input
Replace the slow reader's 30s sleep with a parent-driven wake over a
loopback socket so post-timeout communicate() doesn't block waiting
for the child to wake on its own. Worst-case runtime: ~30s -> <1s.
Add `canonical=False` keyword argument to `a2b_base64`, `a2b_base32`, `a2b_base85`, and `a2b_ascii85` (and their `base64` module wrappers). When `canonical=True`, non-canonical encodings are rejected per [RFC 4648 section 3.5](https://datatracker.ietf.org/doc/html/rfc4648.html#section-3.5).
This is independent of `strict_mode`.
For base85/ascii85, the check also rejects single-character final groups (never produced by a conforming encoder) and verifies partial group padding matches what the encoder would produce.
Co-authored-by: Serhiy Storchaka via lots of great code review!
Improve `hash()` builtin docstring with caveats.
Mention its return type and that the value can be expected to change between
processes (hash randomization).
Why? The `hash` builtin gets reached for and used by a lot of people whether it
is the right tool or not. IDEs surface docstrings and people use pydoc and
`help(hash)`.
* Replaces ad-hoc logic for ending traces with a simple inequality: `fitness < exit_quality`
* Fitness starts high and is reduced for branches, backward edges, calls and trace length
* Exit quality reflect how good a spot that instruction is to end a trace. Closing a loop is very, specializable instructions are very low and the others in between.
Add '+' alternatives to signed_number and signed_real_number grammar
rules, mirroring how unary minus is already handled for pattern matching.
Unary plus is a no-op on numbers so the value is returned directly without
wrapping in a UnaryOp node.
Avoid racing with the owning thread's refcount operations when
immortalizing an interned string: if we don't own it and its refcount
isn't merged, intern a copy we own instead. Use atomic stores in
_Py_SetImmortalUntracked so concurrent atomic reads are race-free.
Improve ABI/feature selection, add new header for it.
Add a test that Python headers themselves don't use
Py_GIL_DISABLED in abi3t: abi3 and abi3t ought to be the
same except the _Py_OPAQUE_PYOBJECT differences.
This is done using the GCC-only poison pragma.
Co-authored-by: Victor Stinner <vstinner@python.org>
Do not mention `__annotations__` dictionaries, as this is slightly
outdated since 3.14.
Rewrite the note about possible exceptions for clarity. Also do not
mention imported type aliases, as since 3.12 aliases with the `type`
statement do not suffer from this limitation anymore.
The documentation previously stated that Concatenate is only valid
when used as the first argument to Callable, but according to PEP 612,
it can also be used when instantiating user-defined generic classes
with ParamSpec parameters.
_PyRawMutex_UnlockSlow CAS-removes the waiter from the list and then
calls _PySemaphore_Wakeup, with no handshake. If _PySemaphore_Wait
returns Py_PARK_INTR, the waiter can destroy its stack-allocated
semaphore before the unlocker's Wakeup runs, causing a fatal error from
ReleaseSemaphore / sem_post.
Loop in _PyRawMutex_LockSlow until _PySemaphore_Wait returns Py_PARK_OK,
which is only signalled when a matching Wakeup has been observed.
Also include GetLastError() and the handle in the Windows fatal messages
in _PySemaphore_Init, _PySemaphore_Wait, and _PySemaphore_Wakeup to make
similar races easier to diagnose in the future.
* Make the `PY_UNWIND` monitoring event available as a code-local
event to allow trapping on function exit events when an exception
bubbles up. This complements the PY_RETURN event by allowing to
catch any function exit event.
* Allow `PY_UNWIND` to be `DISABLE`d; disabling it disables the event for the whole code object.
* Do the above for `PY_THROW`, `RAISE`, `EXCEPTION_HANDLED`, and `RERAISE` events.
