In some cases, previously computed as (nan+nanj), we could recover
meaningful component values in the result, see e.g. the C11, Annex
G.5.1, routine _Cmultd():
>>> z = 1e300+1j
>>> z*(nan+infj) # was (nan+nanj)
(-inf+infj)
That also fix some complex powers for small integer exponents, computed
with optimized algorithm (by squaring):
>>> z**5 # was (nan+nanj)
Traceback (most recent call last):
File "<python-input-1>", line 1, in <module>
z**5
~^^~
OverflowError: complex exponentiation
Ensure `_SelectorSocketTransport.writelines` pauses the protocol if it reaches the high water mark as needed.
Co-authored-by: Kumar Aditya <kumaraditya@python.org>
Remove documentation for `pathlib.Path.scandir()`, and rename the method to
`_scandir()`. In the private pathlib ABCs, make `iterdir()` abstract and
call it from `_scandir()`.
It's not worthwhile to add this method at the moment - see discussion:
https://discuss.python.org/t/ergonomics-of-new-pathlib-path-scandir/71721
Co-authored-by: Steve Dower <steve.dower@microsoft.com>
Objects may be temporarily "resurrected" in destructors when calling
finalizers or watcher callbacks. We previously undid the resurrection
by decrementing the reference count using `Py_SET_REFCNT`. This was not
thread-safe because other threads might be accessing the object
(modifying its reference count) if it was exposed by the finalizer,
watcher callback, or temporarily accessed by a racy dictionary or list
access.
This adds internal-only thread-safe functions for temporary object
resurrection during destructors.
gh-127572: Fix `test_structmembers` initialization.
The 'C' format code expects an `int` as a destination (not a `char`).
This led to test failures on big-endian platforms like s390x. Use the
'c' format code, which expects a `char` as the destination (but requires
a Python byte objects instead of a str).
The CALL family of instructions were mostly thread-safe already and only required a small number of changes, which are documented below.
A few changes were needed to make CALL_ALLOC_AND_ENTER_INIT thread-safe:
Added _PyType_LookupRefAndVersion, which returns the type version corresponding to the returned ref.
Added _PyType_CacheInitForSpecialization, which takes an init method and the corresponding type version and only populates the specialization cache if the current type version matches the supplied version. This prevents potentially caching a stale value in free-threaded builds if we race with an update to __init__.
Only cache __init__ functions that are deferred in free-threaded builds. This ensures that the reference to __init__ that is stored in the specialization cache is valid if the type version guard in _CHECK_AND_ALLOCATE_OBJECT passes.
Fix a bug in _CREATE_INIT_FRAME where the frame is pushed to the stack on failure.
A few other miscellaneous changes were also needed:
Use {LOCK,UNLOCK}_OBJECT in LIST_APPEND. This ensures that the list's per-object lock is held while we are appending to it.
Add missing co_tlbc for _Py_InitCleanup.
Stop/start the world around setting the eval frame hook. This allows us to read interp->eval_frame non-atomically and preserves the behavior of _CHECK_PEP_523 documented below.
* Replace uses of `PyCell_GET` and `PyCell_SET`. These macros are not
safe to use in the free-threaded build. Use `PyCell_GetRef()` and
`PyCell_SetTakeRef()` instead.
* Since `PyCell_GetRef()` returns a strong rather than borrowed ref, some
code restructuring was required, e.g. `frame_get_var()` returns a strong
ref now.
* Add critical sections to `PyCell_GET` and `PyCell_SET`.
* Move critical_section.h earlier in the Python.h file.
* Add `PyCell_GET` to the free-threading howto table of APIs that return
borrowed refs.
* Add additional unit tests for free-threading.
No additional thread safety changes are required. Note that sending to
a generator that is shared between threads is currently not safe in the
free-threaded build.
Fix race in test_start_new_thread_failed
When we succeed in starting a new thread, for example if setrlimit
was ineffective, we must wait for the newly spawned thread to exit.
Otherwise, we run the risk that the newly spawned thread will race
with runtime finalization and access memory that has already been
clobbered/freed.
`_thread.start_new_thread()` only spawns daemon threads, which the runtime
does not wait for at shutdown, and does not return a handle. Use
`_thread.start_joinable_thread()` and join the resulting handle when
the thread is started successfully.
Use existing helpers to atomically modify the bytecode. Add unit tests
to ensure specializing is happening as expected. Add test_specialize.py
that can be used with ThreadSanitizer to detect data races.
Fix thread safety issue with cell_set_contents().
Previously, `traceback.print_list` didn't have a documentation entry and was not exposed in `traceback.__all__`. Now it has a documentation entry and is exposed in `__all__`.
Moves the Emscripten web example into a standalone folder, and updates
Makefile targets to build the web example. Instructions for usage have
also been added.
In the free threading build, if a non-owning thread resizes a list,
it must use QSBR to free the old list array because there may be a
concurrent access (without a lock) from the owning thread.
To match the pattern in dictobject.c, we just mark the list as "shared"
before resizing if it's from a non-owning thread and not already marked
as shared.
