python / cpython

Create importlib._abc submodule to avoid importing typing when
importlib.util is imported. Move Loader ABC into importlib._abc.

test_hashlib emits some warnings when it cannot find some hashes
as it assumes they failed to compile. Since we can disable hashes
through configure, we emit the warnings only in the case that we
did not intentionaly disable them.

Automerge-Triggered-By: @tiran

The pkgutil module now imports lazily the re module to speedup Python
startup time.

The collections module now imports lazily the heapq modules in the
Counter.most_common() method to speedup Python startup time.

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

Automerge-Triggered-By: @tiran

Fix test_copyreg when numpy is installed: test.pickletester now
saves/restores warnings.filters when importing numpy, to ignore
filters installed by numpy.

Add the save_restore_warnings_filters() function to the
test.support.warnings_helper module.

* Rename _PyObject_GC_TRACK_impl() to _PyObject_GC_TRACK()
* Rename _PyObject_GC_UNTRACK_impl() to _PyObject_GC_UNTRACK()
* Omit filename and lineno parameters if NDEBUG is defined.

Co-authored-by: Kyle Stanley <aeros167@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>

There were some minor adjustments needed and a few tests were missing.

https://bugs.python.org/issue32604

…ent line (GH-20875)

Make the _PyTraceMalloc_NewReference() function fully internal:
remove it from the public C API and don't export it anymore.

C and Python coverage jobs of Travis CI are no longer run on pull
requests, only on branches like master.

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Remove an outdated comment on _Py_tracemalloc_config.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