Reduce the complexity from O((M+N)^2) to O(M*N), where M and N are the length
of __args__ for both operands (1 for operand which is not a UnionType).
As a consequence, the complexity of parameter substitution in UnionType has
been reduced from O(N^3) to O(N^2).
Co-authored-by: Yurii Karabas <1998uriyyo@gmail.com>
We're no longer using _Py_IDENTIFIER() (or _Py_static_string()) in any core CPython code. It is still used in a number of non-builtin stdlib modules.
The replacement is: PyUnicodeObject (not pointer) fields under _PyRuntimeState, statically initialized as part of _PyRuntime. A new _Py_GET_GLOBAL_IDENTIFIER() macro facilitates lookup of the fields (along with _Py_GET_GLOBAL_STRING() for non-identifier strings).
https://bugs.python.org/issue46541#msg411799 explains the rationale for this change.
The core of the change is in:
* (new) Include/internal/pycore_global_strings.h - the declarations for the global strings, along with the macros
* Include/internal/pycore_runtime_init.h - added the static initializers for the global strings
* Include/internal/pycore_global_objects.h - where the struct in pycore_global_strings.h is hooked into _PyRuntimeState
* Tools/scripts/generate_global_objects.py - added generation of the global string declarations and static initializers
I've also added a --check flag to generate_global_objects.py (along with make check-global-objects) to check for unused global strings. That check is added to the PR CI config.
The remainder of this change updates the core code to use _Py_GET_GLOBAL_IDENTIFIER() instead of _Py_IDENTIFIER() and the related _Py*Id functions (likewise for _Py_GET_GLOBAL_STRING() instead of _Py_static_string()). This includes adding a few functions where there wasn't already an alternative to _Py*Id(), replacing the _Py_Identifier * parameter with PyObject *.
The following are not changed (yet):
* stop using _Py_IDENTIFIER() in the stdlib modules
* (maybe) get rid of _Py_IDENTIFIER(), etc. entirely -- this may not be doable as at least one package on PyPI using this (private) API
* (maybe) intern the strings during runtime init
https://bugs.python.org/issue46541
It no longer depends on the order of arguments.
hash(int | str) == hash(str | int)
Co-authored-by: Jack DeVries <58614260+jdevries3133@users.noreply.github.com>
* Fix issubclass() for None.
E.g. issubclass(type(None), int | None) returns now True.
* Fix issubclass() for virtual subclasses.
E.g. issubclass(dict, int | collections.abc.Mapping) returns now True.
* Fix crash in isinstance() if the check for one of items raises exception.
Previously this didn't raise an error. Now it will:
```python
from collections.abc import Callable
isinstance(int, list | Callable[..., str])
```
Also added tests in Union since there were previously none for stuff like ``isinstance(list, list | list[int])`` either.
Backport to 3.9 not required.
Automerge-Triggered-By: GH:gvanrossum
Use Py_ssize_t type rather than int, to store lengths in
unionobject.c. Fix the warning:
Objects\unionobject.c(205,1): warning C4244: 'initializing':
conversion from 'Py_ssize_t' to 'int', possible loss of data
Use Py_ssize_t type rather than int, to store lengths in
unionobject.c. Fix warnings:
Objects\unionobject.c(189,71): warning C4244: '+=':
conversion from 'Py_ssize_t' to 'int', possible loss of data
Objects\unionobject.c(182,1): warning C4244: 'initializing':
conversion from 'Py_ssize_t' to 'int', possible loss of data
Objects\unionobject.c(205,1): warning C4244: 'initializing':
conversion from 'Py_ssize_t' to 'int', possible loss of data
Objects\unionobject.c(437,1): warning C4244: 'initializing':
conversion from 'Py_ssize_t' to 'int', possible loss of data
Victor Stinner
Yurii Karabas
Serhiy Storchaka
Oleg Iarygin
Eric Snow
Hasan
Pablo Galindo Salgado
Ken Jin
Neil Schemenauer
Maggie Moss