Currently, calling Py_EnterRecursiveCall() and
Py_LeaveRecursiveCall() may use a function call or a static inline
function call, depending if the internal pycore_ceval.h header file
is included or not. Use a different name for the static inline
function to ensure that the static inline function is always used in
Python internals for best performance. Similar approach than
PyThreadState_GET() (function call) and _PyThreadState_GET() (static
inline function).
* Rename _Py_EnterRecursiveCall() to _Py_EnterRecursiveCallTstate()
* Rename _Py_LeaveRecursiveCall() to _Py_LeaveRecursiveCallTstate()
* pycore_ceval.h: Rename Py_EnterRecursiveCall() to
_Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() and
_Py_LeaveRecursiveCall()
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
Convert the PyType_SUPPORTS_WEAKREFS() macro to a regular function.
It no longer access the PyTypeObject.tp_weaklistoffset member
directly.
Add _PyType_SUPPORTS_WEAKREFS() static inline functions, used
internally by Python for best performance.
Add _PyUnicode_FiniTypes() function, called by
finalize_interp_types(). It clears these static types:
* EncodingMapType
* PyFieldNameIter_Type
* PyFormatterIter_Type
_PyStaticType_Dealloc() now does nothing if tp_subclasses
is not NULL.
Add 'static_exceptions' list to factorize code between
_PyExc_InitTypes() and _PyBuiltins_AddExceptions().
_PyExc_InitTypes() does nothing if it's not the main interpreter.
Sort exceptions in Lib/test/exception_hierarchy.txt.
This change is strictly renames and moving code around. It helps in the following ways:
* ensures type-related init functions focus strictly on one of the three aspects (state, objects, types)
* passes in PyInterpreterState * to all those functions, simplifying work on moving types/objects/state to the interpreter
* consistent naming conventions help make what's going on more clear
* keeping API related to a type in the corresponding header file makes it more obvious where to look for it
https://bugs.python.org/issue46008
The deallocator function of the BaseException type now uses the
trashcan mecanism to prevent stack overflow. For example, when a
RecursionError instance is raised, it can be linked to another
RecursionError through the __context__ attribute or the __traceback__
attribute, and then a chain of exceptions is created. When the chain
is destroyed, nested deallocator function calls can crash with a
stack overflow if the chain is too long compared to the available
stack memory.
To improve the user experience understanding what part of the error messages associated with SyntaxErrors is wrong, we can highlight the whole error range and not only place the caret at the first character. In this way:
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^
SyntaxError: Generator expression must be parenthesized
becomes
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
When printing NameError raised by the interpreter, PyErr_Display
will offer suggestions of simmilar variable names in the function that the exception
was raised from:
>>> schwarzschild_black_hole = None
>>> schwarschild_black_hole
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?
When printing AttributeError, PyErr_Display will offer suggestions of similar
attribute names in the object that the exception was raised from:
>>> collections.namedtoplo
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: namedtuple?
See [PEP 597](https://www.python.org/dev/peps/pep-0597/).
* Add `-X warn_default_encoding` and `PYTHONWARNDEFAULTENCODING`.
* Add EncodingWarning
* Add io.text_encoding()
* open(), TextIOWrapper() emits EncodingWarning when encoding is omitted and warn_default_encoding is enabled.
* _pyio.TextIOWrapper() uses UTF-8 as fallback default encoding used when failed to import locale module. (used during building Python)
* bz2, configparser, gzip, lzma, pathlib, tempfile modules use io.text_encoding().
* What's new entry
Pass the current interpreter (interp) rather than the current Python
thread state (tstate) to internal functions which only use the
interpreter.
Modified functions:
* _PyXXX_Fini() and _PyXXX_ClearFreeList() functions
* _PyEval_SignalAsyncExc(), make_pending_calls()
* _PySys_GetObject(), sys_set_object(), sys_set_object_id(), sys_set_object_str()
* should_audit(), set_flags_from_config(), make_flags()
* _PyAtExit_Call()
* init_stdio_encoding()
* etc.
When allocating MemoryError classes, there is some logic to use
pre-allocated instances in a freelist only if the type that is being
allocated is not a subclass of MemoryError. Unfortunately in the
destructor this logic is not present so the freelist is altered even
with subclasses of MemoryError.
Each interpreter now has its own MemoryError free list: it is not
longer shared by all interpreters.
Add _Py_exc_state structure and PyInterpreterState.exc_state member.
Move also errnomap into _Py_exc_state.
_PyErr_ChainExceptions() now ensures that the first parameter is an
exception type, as done by _PyErr_SetObject().
* The following function now check PyExceptionInstance_Check() in an
assertion using a new _PyBaseExceptionObject_cast() helper
function:
* PyException_GetTraceback(), PyException_SetTraceback()
* PyException_GetCause(), PyException_SetCause()
* PyException_GetContext(), PyException_SetContext()
* PyExceptionClass_Name() now checks PyExceptionClass_Check() with an
assertion.
* Remove XXX comment and add gi_exc_state variable to _gen_throw().
* Remove comment from test_generators
- drop TargetScopeError in favour of raising SyntaxError directly
as per the updated PEP 572
- comprehension iteration variables are explicitly local, but
named expression targets in comprehensions are nonlocal or
global. Raise SyntaxError as specified in PEP 572
- named expression targets in the outermost iterable of a
comprehension have an ambiguous target scope. Avoid resolving
that question now by raising SyntaxError. PEP 572
originally required this only for cases where the bound name
conflicts with the iteration variable in the comprehension,
but CPython can't easily restrict the exception to that case
(as it doesn't know the target variable names when visiting
the outermost iterator expression)
* Add _PyInitError functions:
* _PyInitError_Ok()
* _PyInitError_Error()
* _PyInitError_NoMemory()
* _PyInitError_Exit()
* _PyInitError_IsError()
* _PyInitError_IsExit()
* _PyInitError_Failed()
* frozenmain.c and _testembed.c now use functions rather than macros.
* Move _Py_INIT_xxx() macros to the internal API.
* Move _PyWstrList_INIT macro to the internal API.
Kumar Aditya
Victor Stinner
Irit Katriel
Dong-hee Na
Eric Snow
Mark Shannon
Christian Clauss
Serhiy Storchaka
Pablo Galindo Salgado
Inada Naoki
Erlend Egeberg Aasland
Andy Lester
Nick Coghlan
Min ho Kim
Jeroen Demeyer
Victor Stinner
Max Bernstein