Different libc implementations have different behavior when presented with trailing % in strftime strings. To make test_strftime_trailing_percent more portable, compare the output of datetime.strftime directly to that of time.strftime rather than hardcoding.

Relative imports use resolve_name to get the absolute target name,
which first seeks the current module's absolute package name from the globals:
If __package__ (and __spec__.parent) are missing then
import uses __name__, truncating the last segment if
the module is a submodule rather than a package __init__.py
(which it guesses from whether __path__ is defined).

The __name__ attempt should fail if there is no parent package (top level modules),
if __name__ is '__main__' (-m entry points), or both (scripts).
That is, if both __name__ has no subcomponents and the module does not seem
to be a package __init__ module then import should fail.

A root cause of bpo-37936 is that it's easy to write a .gitignore
rule that's intended to apply to a specific file (e.g., the
`pyconfig.h` generated by `./configure`) but actually applies to all
similarly-named files in the tree (e.g., `PC/pyconfig.h`.)

Specifically, any rule with no non-trailing slashes is applied in an
"unrooted" way, to files anywhere in the tree.  This means that if we
write the rules in the most obvious-looking way, then

 * for specific files we want to ignore that happen to be in
   subdirectories (like `Modules/config.c`), the rule will work
   as intended, staying "rooted" to the top of the tree; but

 * when a specific file we want to ignore happens to be at the root of
   the repo (like `platform`), then the obvious rule (`platform`) will
   apply much more broadly than intended: if someone tries to add a
   file or directory named `platform` somewhere else in the tree, it
   will unexpectedly get ignored.

That's surprising behavior that can make the .gitignore file's
behavior feel finicky and unpredictable.

To avoid it, we can simply always give a rule "rooted" behavior when
that's what's intended, by systematically using leading slashes.

Further, to help make the pattern obvious when looking at the file and
minimize any need for thinking about the syntax when adding new rules:
separate the rules into one group for each type, with brief comments
identifying them.

For most of these rules it's clear whether they're meant to be rooted
or unrooted, but in a handful of cases I've only guessed.  In that
case the safer default (the choice that won't hide information) is the
narrower, rooted meaning, with a leading slash.  If for some of these
the unrooted meaning is desired after all, it'll be easy to move them
to the unrooted section at the top.

Fixes a possible hang when using a timeout on subprocess.run() while
capturing output. If the child process spawned its own children or otherwise
connected its stdout or stderr handles with another process, we could hang
after the timeout was reached and our child was killed when attempting to read
final output from the pipes.

This is a restructuring of the datetime documentation to hopefully make
them more user-friendly and approachable to new users without losing any
of the detail.

Changes include:
 - Creating dedicated subsections for some concepts such as:
    - "Constants"
    - "Naive vs Aware"
    - "Determining if an Object is Aware"
 - Give 'naive vs aware' its own subsection
 - Give 'constants' their own subsection
 - Overhauling the strftime-strptime section by:
    - Breaking it into logical, linkable, and digestable parts
    - Adding a high-level comparison table
    - Moving the technical detail to bottom: readers come to this
      section primarily to remind themselves to things:
      - How do I write the format code for X?
      - strptime/strftime: which one is which again?
 - Touching up fromisoformat + isoformat sections by:
    - Revising fromisoformat + isoformat for date, time, and
      datetime
    - Adding basic examples
    - Enforcing consistency about putting formats (i.e. ``HH:MM``)
      in double backticks.  This was previously done in some places
      but not all
    - Putting long 'supported formats', on their own line to improve
      readability
 - Moving the 'seealso' section to the top and add a link to dateutil
    Rationale: This doesn't really belong nested under the
    'constants' section.  Let readers know right away that
    datetime is one of several related tools.
 - Moving common features of several types into one place:
    Previously, each type went out of its way to note separately
    that it was hashable and picklable.  These can be brought
    into one single place that is more prominent.
 - Reducing some verbose explanations to improve readability
 - Breaking up long paragraphs into digestable chunks
 - Displaying longer "equivalent to" examples, as short code blocks
 - Using the dot notation for datetime/time classes:
    Use :class:`.time` and :class:`.datetime` rather than :class:`time` and
    :class:`datetime`; otherwise, the generated links will route to the
    respective modules, not classes.
 - Rewording the tzinfo class description
    The top paragraph should get straight to the point of telling the reader
    what subclasses of tzinfo _do_.  Previously, that was hidden in a later
    paragraph.
 - Adding a note on .today() versus .now()
 - Rearranging and expanding example blocks, including:
    - Moved long, multiline inline examples to standalone examples
    - Simplified the example block for timedelta arithmetic:
        - Broke the example into two logical sections:
          1. normalization/parameter 'merging'
          2. timedelta arithmetic
        - Reduced the complexity of the some of the examples.  Show
          reasonable, real-world uses cases that are easy to follow
          along with and progres in difficult slightly.
    - Broke up the example sections for date and datetime sections by putting
      the easy examples first, progressing to more esoteric situations and
      breaking it up into logical sections based on what the methods are
      doing at a high level.
    - Simplified the KabulTz example:
        - Put the class definition itself into a non-REPL block since there is
          no interactive output involved there
        - Briefly explained what's happening before launching into the code
        - Broke the example section into visually separate chunks
 - Various whitespace, formatting, style and grammar fixes including:
    - Consistently using backctics for 'date_string' formats
    - Consistently using one space after periods.
    - Consistently using bold for vocab terms
    - Consistently using italics when referring to params:
      See https://devguide.python.org/documenting/#id4
    - Using '::' to lead into code blocks
        Per https://devguide.python.org/documenting/#source-code, this will
        let the reader use the 'expand/collapse' top-right button for REPL
        blocks to hide or show the prompt.
    - Using consistent captialization schemes
    - Removing use of the default role
    - Put 'example' blocks in Markdown subsections

This is a combination of 66 commits.

See bpo-36960: https://bugs.python.org/issue36960

The instance destructor for a type is responsible for preparing
an instance for deallocation by decrementing the reference counts
of its referents.

If an instance belongs to a heap type, the type object of an instance
has its reference count decremented while for static types, which
are permanently allocated, the type object is unaffected by the
instance destructor.

Previously, the default instance destructor searched the class
hierarchy for an inherited instance destructor and, if present,
would invoke it.

Then, if the instance type is a heap type, it would decrement the
reference count of that heap type.  However, this could result in the
premature destruction of a type because the inherited instance
destructor should have already decremented the reference count
of the type object.

This change avoids the premature destruction of the type object
by suppressing the decrement of its reference count when an
inherited, non-default instance destructor has been invoked.

Finally, an assertion on the Py_SIZE of a type was deleted.  Heap
types have a non zero size, making this into an incorrect assertion.

https://github.com/python/cpython/pull/15323

https://bugs.python.org/issue36373

Add unittests for executables with a zipfile appended to test_zipfile, as zipfile.is_zipfile and zipfile.ZipFile work properly on these today.

The `wb.len = -1` assignment is unneeded since its introduction in 161d695f as `PyObject_GetBuffer` always fills it in.

In text mode, the "size" parameter indicates the number of characters, not bytes.

In the table model used by docutils, the `cols` attribute of `tgroup`
nodes is mandatory, see [1]. It is used in texinfo builder in [2].

[1]: https://www.oasis-open.org/specs/tm9901.htm#AEN348
[2]: https://github.com/sphinx-doc/sphinx/blob/v2.1.2/sphinx/writers/texinfo.py#L1129

* Doc: Add texinfo support to the Makefile

https://gitlab.com/python-devs/importlib_metadata/-/tags/0.21

It looks like "cryptographically strong" is the preferred phrase from the surrounding documentation.

Automerge-Triggered-By: @tiran

* Optimize sum() for bools.

* Fix sum([], False).

* Add a NEWS entry.

* Improve doc on open's mode +

* Improve wording

* Address comment from Rémi

Makes the pwd module PEP-384 compatible


https://bugs.python.org/issue38073



Automerge-Triggered-By: @tiran

feed_eof(), feed_data(), set_exception(), and set_transport() are prefixed with underscore now.


https://bugs.python.org/issue38066

Document how $ and % can be escaped in configparser.