python / cpython

When Py_Initialize() is called twice, the second call now updates
more sys attributes for the configuration, rather than only sys.argv.

* Rename _PySys_InitMain() to _PySys_UpdateConfig().
* _PySys_UpdateConfig() now modifies sys.flags in-place, instead of
  creating a new flags object.
* Remove old commented sys.flags flags (unbuffered and skip_first).
* Add private _PySys_GetObject() function.
* When Py_Initialize(), Py_InitializeFromConfig() and

Replace PyModule_AddObject() with PyModule_AddObjectRef() in the
_warnings module to fix a reference leak on error.

Use also PyModule_AddObjectRef() in importdl.c.

Replace PyModule_AddObject() with PyModule_AddObjectRef() in the _ast
module (Python-ast.c).

Replace PyModule_AddObject() with PyModule_AddType() in the
_contextvars module (Python-ast.c).

Add also the module name to _contextvars types name.

* Move orig_argv before argv
* Move program_name and platlibdir with other path configuration
  inputs

Give a name to the PyPreConfig and PyConfig structures and separate
the type definitions.

Added PyModule_AddObjectRef() function: similar to
PyModule_AddObjectRef() but don't steal a reference to the value on
success.

On Unix, the os.device_encoding() function now returns 'UTF-8' rather
than the device encoding if the Python UTF-8 Mode is enabled.

This allows to retrieve the functions that were set in these two, which might differ from sys.gettrace and sys.getprofile within a thread.

…p server (GH-23132)

See https://mail.python.org/archives/list/capi-sig@python.org/thread/T3P2QNLNLBRFHWSKYSTPMVEIL2EEKFJU/ for discussion.

https://bugs.python.org/issue42100

Python 3.10.0a2

Call _PyAST_Fini() on all interpreters, not only on the main
interpreter. Also, call it ealier to fix a reference leak.

Python types contain a reference to themselves in in their
PyTypeObject.tp_mro member. _PyAST_Fini() must called before the last
GC collection to destroy AST types.

_PyInterpreterState_Clear() now calls _PyAST_Fini(). It now also
calls _PyWarnings_Fini() on subinterpeters, not only on the main
interpreter.

Add an assertion in AST init_types() to ensure that the _ast module
is no longer used after _PyAST_Fini() has been called.

The logging.FileHandler class now keeps a reference to the builtin
open() function to be able to open or reopen the file during Python
finalization.

Fix errors like:

    Exception ignored in: (...)
    Traceback (most recent call last):
      (...)
      File ".../logging/__init__.py", line 1463, in error
      File ".../logging/__init__.py", line 1577, in _log
      File ".../logging/__init__.py", line 1587, in handle
      File ".../logging/__init__.py", line 1649, in callHandlers
      File ".../logging/__init__.py", line 948, in handle
      File ".../logging/__init__.py", line 1182, in emit
      File ".../logging/__init__.py", line 1171, in _open
    NameError: name 'open' is not defined

The ast module internal state is now per interpreter.

* Rename "astmodulestate" to "struct ast_state"
* Add pycore_ast.h internal header: the ast_state structure is now
  declared in pycore_ast.h.
* Add PyInterpreterState.ast (struct ast_state)
* Remove get_ast_state()
* Rename get_global_ast_state() to get_ast_state()
* PyAST_obj2mod() now handles get_ast_state() failures

* Prevent some possible DoS attacks via providing invalid Plist files
  with extremely large number of objects or collection sizes.
* Raise InvalidFileException for too large bytes and string size instead of returning garbage.
* Raise InvalidFileException instead of ValueError for specific invalid datetime (NaN).
* Raise InvalidFileException instead of TypeError for non-hashable dict keys.
* Add more tests for invalid Plist files.

GH-22565)

… by level

@vsajip , @pitrou

Automerge-Triggered-By: GH:vsajip

…equest (GH-13893)" (GH-23107)

This reverts commit c415590.

Enhance the documentation of the Python startup, filesystem encoding
and error handling, locale encoding. Add a new "Python UTF-8 Mode"
section.

* Add "locale encoding" and "filesystem encoding and error handler"
  to the glossary
* Remove documentation from Include/cpython/initconfig.h: move it to
  Doc/c-api/init_config.rst.
* Doc/c-api/init_config.rst:

  * Document command line options and environment variables
  * Document default values.

* Add a new "Python UTF-8 Mode" section in Doc/library/os.rst.
* Add warnings to Py_DecodeLocale() and Py_EncodeLocale() docs.
* Document how Python selects the filesystem encoding and error
  handler at a single place: PyConfig.filesystem_encoding and
  PyConfig.filesystem_errors.
* PyConfig: move orig_argv member at the right place.

GH-23067)

This adds a new function named sys._current_exceptions() which is equivalent ot
sys._current_frames() except that it returns the exceptions currently handled
by other threads. It is equivalent to calling sys.exc_info() for each running
thread.

…iterables (GH-23073)

People call wait() and as_completed() with various non-set iterables,
a list should be the most common but there are others as well[1].

Considering typeshed also documents wait()[2] and as_completed()[3]
as accepting arbitrary iterables I think it's a good idea to document
the status quo better.

[1] aio-libs/aiokafka#672
[2] https://github.com/python/typeshed/blob/620989bac572f30349b95590ebe81a73ce0fe862/stdlib/3/asyncio/tasks.pyi#L161
[3] https://github.com/python/typeshed/blob/620989bac572f30349b95590ebe81a73ce0fe862/stdlib/3/asyncio/tasks.pyi#L40

…ontextlib.aclosing() method (GH-21545)

This is a PR to:

 * Add `contextlib.aclosing` which ia analogous to `contextlib.closing` but for async-generators with an explicit test case for [bpo-41229]()
 * Update the docs to describe when we need explicit `aclose()` invocation.

which are motivated by the following issues, articles, and examples:

 * [bpo-41229]()
 * https://github.com/njsmith/async_generator
 * https://vorpus.org/blog/some-thoughts-on-asynchronous-api-design-in-a-post-asyncawait-world/#cleanup-in-generators-and-async-generators
 * https://www.python.org/dev/peps/pep-0533/
 * https://github.com/achimnol/aiotools/blob/ef7bf0cea7af/src/aiotools/context.py#L152

Particuarly regarding [PEP-533](https://www.python.org/dev/peps/pep-0533/), its acceptance (`__aiterclose__()`) would make this little addition of `contextlib.aclosing()` unnecessary for most use cases, but until then this could serve as a good counterpart and analogy to `contextlib.closing()`. The same applies for `contextlib.closing` with `__iterclose__()`.
Also, still there are other use cases, e.g., when working with non-generator objects with `aclose()` methods.

They were occurring with both repeated 'force-calltip' invocations and by typing parentheses
 in expressions, strings, and comments in the argument code.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

…H-13893)

* bpo-37193: remove the thread which finished process request from threads list

* rename variable t to thread.

* don't remove thread from list if it is daemon.

* use lock to protect self._threads.

* use finally block in case of exception from shutdown_request().

* check "not thread.daemon" before lock to avoid holding the lock if it's unnecessary.

* fix the place of _threads_lock.

* separate code to remove a current thread into a function.

* check ValueError when removing thread.

* fix wrong code which all instance shared same lock.

* Extract thread management into a _Threads class to encapsulate atomic operations and separate concerns.

* Replace multiple references of 'block_on_close' with one, avoiding the possibility that 'block_on_close' could change during the course of processing requests. Now, there's exactly one _threads object with behavior fixed for the duration.

* Add docstrings to private classes.

* Add test to ensure that a ThreadingTCPServer can be closed without serving any requests.

* Use _NoThreads as the default value. Fixes AttributeError when server is closed without serving any requests.

* Add blurb

* Add test capturing failure.

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

If the nl_langinfo(CODESET) function returns an empty string, Python
now uses UTF-8 as the filesystem encoding.

In May 2010 (commit b744ba1), I
modified Python to log a warning and use UTF-8 as the filesystem
encoding (instead of None) if nl_langinfo(CODESET) returns an empty
string.

In August 2020 (commit 94908bb), I
modified Python startup to fail with a fatal error and a specific
error message if nl_langinfo(CODESET) returns an empty string. The
intent was to prevent guessing the encoding and also investigate user
configuration where this case happens.

In 10 years (2010 to 2020), I saw zero user report about the error
message related to nl_langinfo(CODESET) returning an empty string.

Today, UTF-8 became the defacto standard and it's safe to make the
assumption that the user expects UTF-8. For example,
nl_langinfo(CODESET) can return an empty string on macOS if the
LC_CTYPE locale is not supported, and UTF-8 is the default encoding
on macOS.

While this change is likely to not affect anyone in practice, it
should make UTF-8 lover happy ;-)

Rewrite also the documentation explaining how Python selects the
filesystem encoding and error handler.

* Rename _Py_GetLocaleEncoding() to _Py_GetLocaleEncodingObject()
* Add _Py_GetLocaleEncoding() which returns a wchar_t* string to
  share code between _Py_GetLocaleEncodingObject()
  and config_get_locale_encoding().
* _Py_GetLocaleEncodingObject() now decodes nl_langinfo(CODESET)
  from the current locale encoding with surrogateescape,
  rather than using UTF-8.

…H-23081)

Noticed by @serhiy-storchaka in the bpo.  `typing`'s types were not showing the parameterized generic. 
Eg. previously:
```python
>>> typing.Union[dict[str, float], list[int]]
'typing.Union[dict, list]'
```
Now:
```python
>>> typing.Union[dict[str, float], list[int]]
'typing.Union[dict[str, float], list[int]]'
```

Automerge-Triggered-By: GH:gvanrossum