Each interpreter now has its own frame free list:
* Move frame free list into PyInterpreterState.
* Add _Py_frame_state structure.
* Add tstate parameter to _PyFrame_ClearFreeList()
and _PyFrame_Fini().
* Remove "#if PyFrame_MAXFREELIST > 0".
* Remove "#ifdef EXPERIMENTAL_ISOLATED_SUBINTERPRETERS".
Each interpreter now has its own float free list:
* Move tuple numfree and free_list into PyInterpreterState.
* Add _Py_float_state structure.
* Add tstate parameter to _PyFloat_ClearFreeList()
and _PyFloat_Fini().
Each interpreter now has its own tuple free lists:
* Move tuple numfree and free_list arrays into PyInterpreterState.
* Define PyTuple_MAXSAVESIZE and PyTuple_MAXFREELIST macros in
pycore_interp.h.
* Add _Py_tuple_state structure. Pass it explicitly to tuple_alloc().
* Add tstate parameter to _PyTuple_ClearFreeList()
* Each interpreter now has its own empty tuple singleton.
If name is NULL, name is now set to co->co_name.
If qualname is NULL, qualname is now set to name.
qualname must not be NULL: it is used to build error messages.
Cleanup also the code: declare variables where they are initialized.
Rename "name" local variables to "varname" to avoid overriding "name"
parameter.
Would be nice to backport to python 3.7+. I don't think it's worth the hassle to backport this all the way down to 3.10. But I'll let the maintainers decide.
This is hard to test because the test setup already includes this [environment variable](https://github.com/python/cpython/blob/master/Lib/test/pythoninfo.py#L292)
Let me know if something doesn't match the PR guidelines. This is my first PR in the python source code.
my_fgets() now calls _PyOS_InterruptOccurred(tstate) to check for
pending signals, rather calling PyOS_InterruptOccurred().
my_fgets() is called with the GIL released, whereas
PyOS_InterruptOccurred() must be called with the GIL held.
test_repl: use text=True and avoid SuppressCrashReport in
test_multiline_string_parsing().
Fix my_fgets() on Windows: fgets(fp) does crash if fileno(fp) is closed.
Refactor formatweekday(), formatmonthname() methods in LocaleHTMLCalendar and LocaleTextCalendar classes in calendar module to call the base class methods. This enables customizable CSS classes for LocaleHTMLCalendar and LocaleTextCalendar.
Patch by Srinivas Reddy Thatiparthy
Fix GIL usage in PyOS_Readline(): lock the GIL to set an exception.
Pass tstate to my_fgets() and _PyOS_WindowsConsoleReadline(). Cleanup
these functions.
Fix :mod:`ssl`` code to be compatible with OpenSSL 1.1.x builds that use
``no-deprecated`` and ``--api=1.1.0``.
Note: Tests assume full OpenSSL API and fail with limited API.
Signed-off-by: Christian Heimes <christian@python.org>
Co-authored-by: Mark Wright <gienah@gentoo.org>
The topological sort functionality that was introduced initially in the
functools module has been moved to a new graphlib module to
better accommodate the new tools and keep the original scope of the
functools module.
Leave selection when right click within. This exception to clearing selections when right-clicking was omitted from the previous commit, 4ca060d. I did not realize that this completely disabled the context menu entries, and I should have merged a minimal fix immediately. An automated test should follow.
* bpo-29882: Add an efficient popcount method for integers
* Update 'sign bit' and versionadded in docs
* Add entry to whatsnew document
* Doc: use positive example, mention population count
* Minor cleanups of the core code
* Move popcount_digit closer to where it's used
* Use z instead of self after conversion
* Add 'absolute value' and 'population count' to docstring
* Fix clinic error about missing summary line
* Ensure popcount_digit is portable with 64-bit ints
Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
* Fix failure of _Py_dg_dtoa to remove trailing zeros
* Add regression test and news entry
* Add explanation about why it's safe to strip trailing zeros
* Make code safer, clean up comments, add change note at top of file
* Nitpick: avoid implicit int-to-float conversion in tests
* bpo-39040: Fix parsing of email headers with encoded-words inside a quoted string.
It is fairly common to find malformed mime headers (especially content-disposition
headers) where the parameter values, instead of being encoded to RFC
standards, are "encoded" by doing RFC 2047 "encoded word" encoding, and
then enclosing the whole thing in quotes. The processing of these malformed
headers was incorrectly leaving the spaces between encoded words in the decoded
text (whitespace between adjacent encoded words is supposed to be stripped on
decoding). This changeset fixes the encoded word processing inside quoted strings
(bare-quoted-string) to do correct RFC 2047 decoding by stripping that
whitespace.
Try to make the meaning of platlibdir clear. The previous wording could
be misinterpreted to suggest that it will be used to find all shared
libraries on the system, and not just Python extensions. Furthermore,
it was unclear whether it affects third-party (site-packages) extensions
or not. The new wording tries to make its dual purpose clear,
and provide the additional example of extensions in site-packages.
Recent changes to _datetimemodule broke compilation on mingw; see the comments in this change for details.
FWIW, @corona10: this issue is why `PyType_FromModuleAndSpec` & friends take the `bases` argument at run time.
On macOS, socket.getaddrinfo() no longer uses an internal lock to
prevent race conditions when calling getaddrinfo(). getaddrinfo is
thread-safe is macOS 10.5, whereas Python 3.9 requires macOS 10.6 or
newer.
The lock was also used on FreeBSD older than 5.3, OpenBSD older than
201311 and NetBSD older than 4.
Previously, the result could have been an instance of a subclass of int.
Also revert bpo-26202 and make attributes start, stop and step of the range
object having exact type int.
Add private function _PyNumber_Index() which preserves the old behavior
of PyNumber_Index() for performance to use it in the conversion functions
like PyLong_AsLong().
If ctypes fails to convert the result of a callback or if a ctypes
callback function raises an exception, sys.unraisablehook is now
called with an exception set. Previously, the error was logged into
stderr by PyErr_Print().
hashlib.compare_digest uses OpenSSL's CRYPTO_memcmp() function
when OpenSSL is available.
Note: The _operator module is a builtin module. I don't want to add
libcrypto dependency to libpython. Therefore I duplicated the wrapper
function and added a copy to _hashopenssl.c.
ctypes now raises an ArgumentError when a callback
is invoked with more than 1024 arguments.
The ctypes module allocates arguments on the stack in
ctypes_callproc() using alloca(), which is problematic
when large numbers of arguments are passed. Instead
of a stack overflow, this commit raises an ArgumentError
if more than 1024 parameters are passed.
Convert Py_REFCNT() and Py_SIZE() macros to static inline functions.
They cannot be used as l-value anymore: use Py_SET_REFCNT() and
Py_SET_SIZE() to set an object reference count and size.
Replace &Py_SIZE(self) with &((PyVarObject*)self)->ob_size
in arraymodule.c.
This change is backward incompatible on purpose, to prepare the C API
for an opaque PyObject structure.
The 'extra' argument is not always used by custom logger adapters. For
example:
```python
class IndentAdapter(logging.LoggerAdapter):
def process(self, msg, kwargs):
indent = kwargs.pop(indent, 1)
return ' ' * indent + msg, kwargs
```
It is cleaner and friendlier to default the 'extra' argument to None
instead of either forcing the subclasses of LoggerAdapter to pass a None
value directly or to override the constructor.
This change is backward compatible because existing calls to
`LoggerAdapter.__init__` are already passing a value for the second
argument.
Automerge-Triggered-By: @vsajip
When a `SyntaxError` in the expression part of a fstring is found,
the filename attribute of the `SyntaxError` is always `<fstring>`.
With this commit, it gets changed to always have the name of the file
the fstring resides in.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
:mod:`hashlib` no longer falls back to builtin hash implementations when
OpenSSL provides a hash digest and the algorithm is blocked by security
policy.
Signed-off-by: Christian Heimes <christian@python.org>
This updates _PyErr_ChainStackItem() to use _PyErr_SetObject()
instead of _PyErr_ChainExceptions(). This prevents a hang in
certain circumstances because _PyErr_SetObject() performs checks
to prevent cycles in the exception context chain while
_PyErr_ChainExceptions() doesn't.
The reset_peak function sets the peak memory size to the current size,
representing a resetting of that metric. This allows for recording the
peak of specific sections of code, ignoring other code that may have
had a higher peak (since the most recent `tracemalloc.start()` or
tracemalloc.clear_traces()` call).
- Fix upload test on systems that blocks MD5
- Add SHA2-256 and Blake2b-256 digests based on new Warehous and twine
specs.
Signed-off-by: Christian Heimes <christian@python.org>
* PEP 554 for use in test suite
* 📜🤖 Added by blurb_it.
* Fix space
* Add doc to doc tree
* Move to modules doc tree
* Fix suspicious doc errors
* Fix test__all
* Docs docs docs
* Support isolated and fix wait
* Fix white space
* Remove undefined from __all__
* Fix recv and add exceptions
* Remove unused exceptions, fix pep 8 formatting errors and fix _NOT_SET in recv_nowait()
Co-authored-by: nanjekyejoannah <joannah.nanjekye@ibm.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Without this, only the _zoneinfo module is getting installed, not the
zoneinfo module. I believe this was not noticed earlier because
test.test_zoneinfo was also not being installed.
Implements `asyncio.to_thread`, a coroutine for asynchronously running IO-bound functions in a separate thread without blocking the event loop. See the discussion starting from [here](https://github.com/python/cpython/pull/18410#issuecomment-628930973) in GH-18410 for context.
Automerge-Triggered-By: @aeros
This reverts commit 0da5466650.
The commit is causing make failures on a FreeBSD buildbot.
Due to the imminent 3.9.0b1 cutoff, revert this commit for
now pending further investigation.
Add support to the configure script for OBJC and OBJCXX command line options so that the macOS builds can use the clang compiler for the macOS-specific Objective C source files. This allows third-party compilers, like GNU gcc, to be used to build the rest of the project since some of the Objective C system header files are not compilable by GNU gcc.
Co-authored-by: Jeffrey Kintscher <websurfer@surf2c.net>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
_tkinter now builds and links with non-system Tcl and Tk frameworks if they
are installed in /Library/Frameworks as had been the case on older releases
of macOS. If a macOS SDK is explicitly configured, by using ./configure
--enable-universalsdk= or -isysroot, only a Library/Frameworks directory in
the SDK itself is searched. The default behavior can still be overridden with
configure --with-tcltk-includes and --with-tcltk-libs.
Ifdef is not necessary, as AF_INET6 is supported from Windows Vista, and other code in overlapped.c uses AF_INET6 and is not ifdef'd.
Change the raised exception so users are not fooled to think it comes from Windows API.
Automerge-Triggered-By: @njsmith
When an asyncio.Task is cancelled, the exception traceback now
starts with where the task was first interrupted. Previously,
the traceback only had "depth one."
This was not specified in the PEP, but it will likely be a frequently requested feature if it's not included.
This includes only the "canonical" zones, not a simple listing of every valid value of `key` that can be passed to `Zoneinfo`, because it seems likely that that's what people will want.
The internal module ``_hashlib`` wraps and exposes OpenSSL's HMAC API. The
new code will be used in Python 3.10 after the internal implementation
details of the pure Python HMAC module are no longer part of the public API.
The code is based on a patch by Petr Viktorin for RHEL and Python 3.6.
Co-Authored-By: Petr Viktorin <encukou@gmail.com>
{date, datetime}.isocalendar() now return a private custom named tuple object
IsoCalendarDate rather than a simple tuple.
In order to leave IsocalendarDate as a private class and to improve what
backwards compatibility is offered for pickling the result of a
datetime.isocalendar() call, add a __reduce__ method to the named tuples that
reduces them to plain tuples. (This is the part of this PR most likely to cause
problems — if it causes major issues, switching to a strucseq or equivalent
would be prudent).
The pure python implementation of IsoCalendarDate uses positional-only
arguments, since it is private and only constructed by position anyway; the
equivalent change in the argument clinic on the C side would require us to move
the forward declaration of the type above the clinic import for whatever
reason, so it seems preferable to hold off on that for now.
bpo-24416: https://bugs.python.org/issue24416
Original PR by Dong-hee Na with only minor alterations by Paul Ganssle.
Co-authored-by: Dong-hee Na <donghee.na92@gmail.com>
On AIX, time.thread_time() is now implemented with thread_cputime()
which has nanosecond resolution, rather than
clock_gettime(CLOCK_THREAD_CPUTIME_ID) which has a resolution of 10 ms.
This is the initial implementation of PEP 615, the zoneinfo module,
ported from the standalone reference implementation (see
https://www.python.org/dev/peps/pep-0615/#reference-implementation for a
link, which has a more detailed commit history).
This includes (hopefully) all functional elements described in the PEP,
but documentation is found in a separate PR. This includes:
1. A pure python implementation of the ZoneInfo class
2. A C accelerated implementation of the ZoneInfo class
3. Tests with 100% branch coverage for the Python code (though C code
coverage is less than 100%).
4. A compile-time configuration option on Linux (though not on Windows)
Differences from the reference implementation:
- The module is arranged slightly differently: the accelerated module is
`_zoneinfo` rather than `zoneinfo._czoneinfo`, which also necessitates
some changes in the test support function. (Suggested by Victor
Stinner and Steve Dower.)
- The tests are arranged slightly differently and do not include the
property tests. The tests live at test/test_zoneinfo/test_zoneinfo.py
rather than test/test_zoneinfo.py or test/test_zoneinfo/__init__.py
because we may do some refactoring in the future that would likely
require this separation anyway; we may:
- include the property tests
- automatically run all the tests against both pure Python and C,
rather than manually constructing C and Python test classes (similar
to the way this works with test_datetime.py, which generates C
and Python test cases from datetimetester.py).
- This includes a compile-time configuration option on Linux (though not
on Windows); added with much help from Thomas Wouters.
- Integration into the CPython build system is obviously different from
building a standalone zoneinfo module wheel.
- This includes configuration to install the tzdata package as part of
CI, though only on the coverage jobs. Introducing a PyPI dependency as
part of the CI build was controversial, and this is seen as less of a
major change, since the coverage jobs already depend on pip and PyPI.
Additional changes that were introduced as part of this PR, most / all of
which were backported to the reference implementation:
- Fixed reference and memory leaks
With much debugging help from Pablo Galindo
- Added smoke tests ensuring that the C and Python modules are built
The import machinery can be somewhat fragile, and the "seamlessly falls
back to pure Python" nature of this module makes it so that a problem
building the C extension or a failure to import the pure Python version
might easily go unnoticed.
- Adjustments to zoneinfo.__dir__
Suggested by Petr Viktorin.
- Slight refactorings as suggested by Steve Dower.
- Removed unnecessary if check on std_abbr
Discovered this because of a missing line in branch coverage.
OpenSSL can be build without support for TLS 1.0 and 1.1. The ssl module
now correctly adheres to OPENSSL_NO_TLS1 and OPENSSL_NO_TLS1_1 flags.
Also update multissltest to test with latest OpenSSL and LibreSSL
releases.
Signed-off-by: Christian Heimes <christian@python.org>
Automerge-Triggered-By: @tiran
Currently, if asyncio.wait_for() timeout expires, it cancels
inner future and then always raises TimeoutError. In case
those future is task, it can handle cancelation mannually,
and those process can lead to some other exception. Current
implementation silently loses thoses exception.
To resolve this, wait_for will check was the cancelation
successfull or not. In case there was exception, wait_for
will reraise it.
Co-authored-by: Roman Skurikhin <roman.skurikhin@cruxlab.com>
The ``ssl`` and ``hashlib`` modules now actively check that OpenSSL is
build with thread support. Python 3.7.0 made thread support mandatory and no
longer works safely with a no-thread builds.
Signed-off-by: Christian Heimes <christian@python.org>
* 1.0.2u (EOL)
* 1.1.0l (EOL)
* 1.1.1g
* 3.0.0-alpha2 (disabled for now)
Build the FIPS provider and create a FIPS configuration file for OpenSSL
3.0.0.
Signed-off-by: Christian Heimes <christian@python.org>
Automerge-Triggered-By: @tiran
OpenSSL 3.0.0-alpha2 was released today. The FIPS_mode() function has
been deprecated and removed. It no longer makes sense with the new
provider and context system in OpenSSL 3.0.0.
EVP_default_properties_is_fips_enabled() is good enough for our needs in
unit tests. It's an internal API, too.
Signed-off-by: Christian Heimes <christian@python.org>
distutils.tests now saves/restores warnings filters to leave them
unchanged. Importing tests imports docutils which imports
pkg_resources which adds a warnings filter.
This fixes both the traceback.py module and the C code for formatting syntax errors (in Python/pythonrun.c). They now both consistently do the following:
- Suppress caret if it points left of text
- Allow caret pointing just past end of line
- If caret points past end of line, clip to *just* past end of line
The syntax error formatting code in traceback.py was mostly rewritten; small, subtle changes were applied to the C code in pythonrun.c.
There's still a difference when the text contains embedded newlines. Neither handles these very well, and I don't think the case occurs in practice.
Automerge-Triggered-By: @gvanrossum
compileall is now able to use hardlinks to prevent duplicates in a
case when .pyc files for different optimization levels have the same content.
Co-authored-by: Miro Hrončok <miro@hroncok.cz>
Co-authored-by: Victor Stinner <vstinner@python.org>
raw_data_manager (default for EmailPolicy, EmailMessage)
does correct wrapping of 'text' parts as long as the message contains
characters outside of 7bit US-ASCII set: base64 or qp
Content-Transfer-Encoding is applied if the lines would be too long
without it. It did not, however, do this for ascii-only text,
which could result in lines that were longer than
policy.max_line_length or even the rfc 998 maximum.
This changeset fixes the heuristic so that if lines are longer than
policy.max_line_length, it will always apply a
content-transfer-encoding so that the lines are wrapped correctly.
With the new parser, the error message contains always the trailing
newlines, causing the comparison of the repr of the error messages
in codeop to fail. This commit makes the new parser mirror the old parser's
behaviour regarding trailing newlines.
* bpo-37986: Improve perfomance of PyLong_FromDouble()
* Use strict bound check for safety and symmetry
* Remove possibly outdated performance claims
Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
Convert posixmodule.c ("posix" or "nt" module) to the multiphase
initialization (PEP 489).
* Create the module using PyModuleDef_Init().
* Create ScandirIteratorType and DirEntryType with the new
PyType_FromModuleAndSpec() (PEP 573)
* Get the module state from ScandirIteratorType and DirEntryType with
the new PyType_GetModule() (PEP 573)
* Pass module to functions which access the module state.
* convert_sched_param() gets a new module parameter. It is now called
directly since Argument Clinic doesn't support passing the module
to an argument converter callback.
* Remove _posixstate_global macro.
* bpo-39791: Update importlib.resources to support files() API (importlib_resources 1.5).
* 📜🤖 Added by blurb_it.
* Add some documentation about the new objects added.
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Declare _PyErr_GetTopmostException() with PyAPI_FUNC() to properly
export the function in the C API. The function remains private
("_Py") prefix.
Co-Authored-By: Julien Danjou <julien@danjou.info>
Module C state is now accessible from C-defined heap type methods (PEP 573).
Patch by Marcel Plch and Petr Viktorin.
Co-authored-by: Marcel Plch <mplch@redhat.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
Add --with-experimental-isolated-subinterpreters build option to
configure: better isolate subinterpreters, experimental build mode.
When used, force the usage of the libc malloc() memory allocator,
since pymalloc relies on the unique global interpreter lock (GIL).
Due to backwards compatibility concerns regarding keywords immediately followed by a string without whitespace between them (like in `bg="#d00" if clear else"#fca"`) will fail to parse,
commit 41d5b94af4 has to be reverted.
Before this commit, if an exception was active inside a generator
when calling gen.throw(), that exception was lost (i.e. there was
no implicit exception chaining). This commit fixes that by
setting exc.__context__ when calling gen.throw(exc).
I can add another commit with the new test case I wrote to verify that the warning was being printed before my change, stopped printing after my change, and that the function does not return null after my change.
Automerge-Triggered-By: @brettcannon
Otherwise we leave a dangling pointer to free'd memory. If we
then initialize a new interpreter in the same process and call
PyImport_ExtendInittab, we will (likely) crash when calling
PyMem_RawRealloc(inittab_copy, ...) since the pointer address
is bogus.
Automerge-Triggered-By: @brettcannon
An isolated subinterpreter cannot spawn threads, spawn a child
process or call os.fork().
* Add private _Py_NewInterpreter(isolated_subinterpreter) function.
* Add isolated=True keyword-only parameter to
_xxsubinterpreters.create().
* Allow again os.fork() in "non-isolated" subinterpreters.
Before this commit, if an exception was active inside a generator
when calling gen.throw(), then that exception was lost (i.e. there
was no implicit exception chaining). This commit fixes that.
Remove _random.Random.randbytes(): the C implementation of
randbytes(). Implement the method in Python to ease subclassing:
randbytes() now directly reuses getrandbits().
New PyFrame_GetBack() function: get the frame next outer frame.
Replace frame->f_back with PyFrame_GetBack(frame) in most code but
frameobject.c, ceval.c and genobject.c.
Remove the following function from the C API:
* PyAsyncGen_ClearFreeLists()
* PyContext_ClearFreeList()
* PyDict_ClearFreeList()
* PyFloat_ClearFreeList()
* PyFrame_ClearFreeList()
* PyList_ClearFreeList()
* PySet_ClearFreeList()
* PyTuple_ClearFreeList()
Make these functions private, move them to the internal C API and
change their return type to void.
Call explicitly PyGC_Collect() to free all free lists.
Note: PySet_ClearFreeList() did nothing.
PyFrame_GetCode(frame): return a borrowed reference to the frame
code.
Replace frame->f_code with PyFrame_GetCode(frame) in most code,
except in frameobject.c, genobject.c and ceval.c.
Also add PyFrame_GetLineNumber() to the limited C API.
Adds a short description of `PyDoc_STRVAR` and `PyDoc_STR` to "Useful macros" section of C-API docs.
Currently, there is [one lone mention](https://docs.python.org/3/c-api/module.html?highlight=pydoc_strvar#c.PyModuleDef) in the C-API reference, despite the fact that `PyDoc_STRVAR` is ubiquitous to `Modules/`.
Additionally, this properly uses `c:macro` within `Doc/c-api/module.rst` to link.
This is one of the few files that has intimate knowledge of the pyc file
format. Since it lacks tests it tends to become outdated fairly quickly.
At present it has been broken since the introduction of PEP 552.
Optimize the subprocess module on FreeBSD using closefrom().
A single close(fd) syscall is cheap, but when sysconf(_SC_OPEN_MAX)
is high, the loop calling close(fd) on each file descriptor can take
several milliseconds.
The workaround on FreeBSD to improve performance was to load and
mount the fdescfs kernel module, but this is not enabled by default.
Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans
(kevans) and Kubilay Kocak (koobs):
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274
On FreeBSD, os.closerange(fd_low, fd_high) now calls
closefrom(fd_low) if fd_high is greater than or equal to
sysconf(_SC_OPEN_MAX).
Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans
(kevans) and Kubilay Kocak (koobs):
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274
Added str.removeprefix and str.removesuffix methods and corresponding
bytes, bytearray, and collections.UserString methods to remove affixes
from a string if present. See PEP 616 for a full description.
Fix the Windows implementation of os.waitpid() for exit code
larger than "INT_MAX >> 8". The exit status is now interpreted as an
unsigned number.
os.waitstatus_to_exitcode() now accepts wait status larger than
INT_MAX.
Previously, python.org macOS installers did not alter the Current version
symlink in /Library/Frameworks/Python.framework/Versions when installing
a version of Python 3.x, only when installing 2.x. Now that Python 2 is
retired, it's time to change that. This should make it a bit easier
to embed Python 3 into other macOS applications.
It is possible to use either '-isysroot /some/path' (with a space) or
'-isysroot/some/path' (no space in between). Support both forms in
places where special handling of -isysroot is done, rather than just
the first form.
Co-authored-by: Ned Deily <nad@python.org>
Avoid linear runtime of ShareableList.__getitem__ and
ShareableList.__setitem__ by storing running allocated bytes in
ShareableList._allocated_bytes instead of the number of bytes for
a particular stored item.
Co-authored-by: Antoine Pitrou <antoine@python.org>