In Lexical Analysis f-strings section, NULL in the description
of 'literal character' means '\0'. In the format_spec grammar
production, it is wrong with that meaning and redundant if
instead interpreted as <nothing>. Remove it there.
Even though it has no internal references to Python objects it still
has a reference to its type by virtue of being a heap type. We need
to provide a traverse function that visits the type, but we do not
need to provide a clear function.
Stop raising `ValueError` from `glob.translate()` when a `**` sub-string
appears in a non-recursive pattern segment. This matches `glob.glob()`
behaviour.
* Update titles and subtitles on landing page template
* address review from gvanrossum
* Edits from hugovk review
* Change word order back. Down the road we should split license and history
There is a race between when `Thread._tstate_lock` is released[^1] in `Thread._wait_for_tstate_lock()`
and when `Thread._stop()` asserts[^2] that it is unlocked. Consider the following execution
involving threads A, B, and C:
1. A starts.
2. B joins A, blocking on its `_tstate_lock`.
3. C joins A, blocking on its `_tstate_lock`.
4. A finishes and releases its `_tstate_lock`.
5. B acquires A's `_tstate_lock` in `_wait_for_tstate_lock()`, releases it, but is swapped
out before calling `_stop()`.
6. C is scheduled, acquires A's `_tstate_lock` in `_wait_for_tstate_lock()` but is swapped
out before releasing it.
7. B is scheduled, calls `_stop()`, which asserts that A's `_tstate_lock` is not held.
However, C holds it, so the assertion fails.
The race can be reproduced[^3] by inserting sleeps at the appropriate points in
the threading code. To do so, run the `repro_join_race.py` from the linked repo.
There are two main parts to this PR:
1. `_tstate_lock` is replaced with an event that is attached to `PyThreadState`.
The event is set by the runtime prior to the thread being cleared (in the same
place that `_tstate_lock` was released). `Thread.join()` blocks waiting for the
event to be set.
2. `_PyInterpreterState_WaitForThreads()` provides the ability to wait for all
non-daemon threads to exit. To do so, an `is_daemon` predicate was added to
`PyThreadState`. This field is set each time a thread is created. `threading._shutdown()`
now calls into `_PyInterpreterState_WaitForThreads()` instead of waiting on
`_tstate_lock`s.
[^1]: 441affc9e7/Lib/threading.py (L1201)
[^2]: 441affc9e7/Lib/threading.py (L1115)
[^3]: 8194653279
---------
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Antoine Pitrou <antoine@python.org>
Change automatically generated tkinter.Checkbutton widget names to
avoid collisions with automatically generated tkinter.ttk.Checkbutton
widget names within the same parent widget.
* Restore support of None and other false values.
* Raise TypeError for non-zero integers and non-empty sequences.
The regressions were introduced in gh-74668
(bdba8ef42b).
Any capitalization of "xn--" should be acceptable for the ACE prefix
(see https://tools.ietf.org/html/rfc3490#section-5).
Co-authored-by: Pepijn de Vos <pepijndevos@gmail.com>
Co-authored-by: Erlend E. Aasland <erlend@python.org>
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Since 3.12, allocating a GC object cannot immediately trigger GC. This
allows us to simplify the logic for creating the canonical callback-less
weakref.
Use the NtQueryInformationProcess system call to efficiently retrieve the parent process ID in a single step, rather than using the process snapshots API which retrieves large amounts of unnecessary information and is more prone to failure (since it makes heap allocations).
Includes a fallback to the original win32_getppid implementation in case the unstable API appears to return strange results.
