Returning EINTR from pthread semaphore or lock acquisition is an optional POSIX
feature. musl does not provide this feature, so some threadsignal tests fail
when Python is built against it.
There's no good way to test for musl, so we skip if we're on Linux and not using
glibc pthreads.
Also, hedge in the threading documentation about when we can provide interrupts
from lock acquisition.
Store a weak reference to stream readerfor breaking strong references
It breaks the strong reference loop between reader and protocol and allows to detect and close the socket if the stream is deleted (garbage collected)
It is unused.
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Address a C undefined behavior signed integer overflow issue in set object table resizing. Our -fwrapv compiler flag and practical reasons why sets are unlikely to get this large should mean this was never an issue but it was incorrect code that generates code analysis warnings.
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Followup to 90fc8980bb.
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GCC complains:
Python/pylifecycle.c: In function ‘_Py_InitializeFromConfig’:
Python/pylifecycle.c:900:13: warning: ‘interp’ may be used uninitialized in this function [-Wmaybe-uninitialized]
err = _Py_InitializeMainInterpreter(interp, &main_config);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This seems spurious since &interp is passed to _Py_InitializeCore. Anyway, we
can easily initialize to quiet the warning.
Although the kernel accepts any negative value for timeout, the
documented value to block indefinitely is -1.
This commit also makes the code similar to select.poll.poll().
When subprocess.Popen() stdin= stdout= or stderr= handles are specified
and appear in pass_fds=, don't close the original fds after dup'ing them.
This implementation and unittest primarily came from @izbyshev (see the PR)
See also b89b52f284
This also removes the old manual p2cread, c2pwrite, and errwrite closing logic
as inheritable flags and _close_open_fds takes care of that properly today without special treatment.
This code is within child_exec() where it is the only thread so there is no
race condition between the dup and _Py_set_inheritable_async_safe call.