python / cpython

Co-authored-by: Arfrever Frehtes Taifersar Arahesis <arfrever.fta@gmail.com>

GH-20888)

When a file ends with a line that contains a line continuation character
the text of the emitted SyntaxError is empty, contrary to the old
parser, where the error text contained the text of the last line.

Co-authored-by: Benjamin Peterson <benjamin@python.org>

)

The PyObject_INIT() and PyObject_INIT_VAR() macros become aliases to,
respectively, PyObject_Init() and PyObject_InitVar() functions.

Rename _PyObject_INIT() and _PyObject_INIT_VAR() static inline
functions to, respectively, _PyObject_Init() and _PyObject_InitVar(),
and move them to pycore_object.h. Remove their return value:
their return type becomes void.

The _datetime module is now built with the Py_BUILD_CORE_MODULE macro
defined.

Remove an outdated comment on _Py_tracemalloc_config.

The C99 functions snprintf() and vsnprintf() are now required
to build Python.

PyOS_snprintf() and PyOS_vsnprintf() no longer call Py_FatalError().
Previously, they called Py_FatalError() on a buffer overflow on platforms
which don't provide vsnprintf().

On Windows, #include "pyerrors.h" no longer defines "snprintf" and
"vsnprintf" macros.

PyOS_snprintf() and PyOS_vsnprintf() should be used to get portable
behavior.

Replace snprintf() calls with PyOS_snprintf() and replace vsnprintf()
calls with PyOS_vsnprintf().

ensurepip optionally installs or upgrades 'pip' and 'setuptools' using
the version of those modules bundled with Python.  The internal PIP
installation routine by default temporarily uses its cache, if it
exists.  This is undesirable as Python builds and installations may be
independent of the user running the build, whilst PIP cache location
is dependent on the user's environment and outside of the build
environment.

At the same time, there's no value in using the cache while installing
bundled modules.

This change disables PIP caching when used in ensurepip.

In Python 3.7 the behavior of parse_multipart changed requiring CONTENT-LENGTH
header, this fix remove this header as required and fix FieldStorage
read_lines_to_outerboundary, by not using limit when it's negative,
since by default it's -1 if not content-length and keeps substracting what
was read from the file object.

Also added a test case for this problem.

bpo-40910, bpo-40953: PyConfig_Clear() clears _orig_argv.

In GH-2866, _Py_Bit_Length() was added to pymath.h for lack of a better
location. GH-20518 added a more appropriate header file for bit utilities. It
also shows how to properly use intrinsics. This allows reconsidering bpo-29782.

* Move the function to the new header.
* Changed return type to match __builtin_clzl() and reviewed usage.
* Use intrinsics where available.
* Pick a fallback implementation suitable for inlining.

GH-20563)

Automerge-Triggered-By: @vsajip

Fixes two outdated URLs to point at the current "stable" version of Django's logging documentation.

Automerge-Triggered-By: @vsajip

Using a log2n way to fill a much smaller buffer, and receiving in a cleaner way with EOF.

The failing test was reproducible using the following command thanks to @aeros :

```bash
./python -m test test_asyncio.test_sock_lowlevel --match test_sock_client_racing -j100 -F -v
```

According to test results, we may still need to bump the timeout:

https://github.com/python/cpython/blob/5aad027db9618f22f6fa2274e05dd50f928d2ed7/Lib/test/test_asyncio/test_sock_lowlevel.py#L256-L257

Signed-off-by: Christian Heimes <christian@python.org>

Modify the help in cpython/PC/launcher.c to show users that "latest" can be overridden by shebang, PY_PYTHON[n] or py.ini files. Also show that script [args] is optional by enclosing in square brackets.

Automerge-Triggered-By: @zooba

Remove duplication in `threading.Thread.native_id` documentation, so resulting documentation is more consistent with the `threading.Thread.ident`.

Issue initially raised [here](python/python-docs-fr#1122 (comment)) (in French). 

No issue associated to this PR.

Automerge-Triggered-By: @csabella

Remote host cyrus.andrew.cmu.edu is blocking incoming connections and is
causing test suite to fail.

Signed-off-by: Christian Heimes <christian@python.org>

```
Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x7f008bf19667 in __interceptor_malloc (/lib64/libasan.so.6+0xb0667)
    #1 0x7f007a0bee4a in subprocess_fork_exec /home/heimes/dev/python/cpython/Modules/_posixsubprocess.c:774
    #2 0xe0305b in cfunction_call Objects/methodobject.c:546
```

Signed-off-by: Christian Heimes <christian@python.org>

Use Sphinx role markup for `str.format`.

Automerge-Triggered-By: @csabella