* Add test for inheriting explicit __dict__ and weakref.
* Restore 3.10 behavior for multiple inheritance of C extension classes that store their dictionary at the end of the struct.
* Store tp_weaklist on the interpreter state for static builtin types.
* Factor out _PyStaticType_GET_WEAKREFS_LISTPTR().
* Add _PyStaticType_ClearWeakRefs().
* Add a comment about how _PyStaticType_ClearWeakRefs() loops.
* Document the change.
* Update Doc/whatsnew/3.12.rst
* Fix a typo.
This is the last precursor to storing tp_subclasses (and tp_weaklist) on the interpreter state for static builtin types.
Here we add per-type storage on PyInterpreterState, but only for the static builtin types. This involves the following:
* add PyInterpreterState.types
* move PyInterpreterState.type_cache to it
* add a "num_builtins_initialized" field
* add a "builtins" field (a static array big enough for all the static builtin types)
* add _PyStaticType_GetState() to look up a static builtin type's state
* (temporarily) add PyTypeObject.tp_static_builtin_index (to hold the type's index into PyInterpreterState.types.builtins)
We will be eliminating tp_static_builtin_index in a later change.
Static builtin types are finalized by calling _PyStaticType_Dealloc(). Before this change, we were skipping finalizing such a type if it still had subtypes (i.e. its tp_subclasses hadn't been cleared yet). The problem is that types hold several heap objects, which leak if we skip the type's finalization. This change addresses that.
For context, there's an old comment (from e9e3eab0b8) that says the following:
// If a type still has subtypes, it cannot be deallocated.
// A subtype can inherit attributes and methods of its parent type,
// and a type must no longer be used once it's deallocated.
However, it isn't clear that is actually still true. Clearing tp_dict should mean it isn't a problem.
Furthermore, the only subtypes that might still be around come from extension modules that didn't clean them up when unloaded (i.e. extensions that do not implement multi-phase initialization, AKA PEP 489). Those objects are already leaking, so this change doesn't change anything in that regard. Instead, this change means more objects gets cleaned up that before.
This is the first of several precursors to storing tp_subclasses (and tp_weaklist) on the interpreter state for static builtin types.
We do the following:
* add `_PyStaticType_InitBuiltin()`
* add `_Py_TPFLAGS_STATIC_BUILTIN`
* set it on all static builtin types in `_PyStaticType_InitBuiltin()`
* shuffle some code around to be able to use _PyStaticType_InitBuiltin()
* rename `_PyStructSequence_InitType()` to `_PyStructSequence_InitBuiltinWithFlags()`
* add `_PyStructSequence_InitBuiltin()`.
Move the follow functions and type from frameobject.h to pyframe.h,
so the standard <Python.h> provide frame getter functions:
* PyFrame_Check()
* PyFrame_GetBack()
* PyFrame_GetBuiltins()
* PyFrame_GetGenerator()
* PyFrame_GetGlobals()
* PyFrame_GetLasti()
* PyFrame_GetLocals()
* PyFrame_Type
Remove #include "frameobject.h" from many C files. It's no longer
needed.
When changing PyType_FromMetaclass recently (GH-93012, GH-93466, GH-28748)
I found a bunch of opportunities to improve the code. Here they are.
Fixes: #89546
Automerge-Triggered-By: GH:encukou
This checks the bases of of a type created using the FromSpec
API to inherit the bases metaclasses. The metaclass's alloc
function will be called as is done in `tp_new` for classes
created in Python.
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@protonmail.com>
This was added for bpo-40514 (gh-84694) to test out a per-interpreter GIL. However, it has since proven unnecessary to keep the experiment in the repo. (It can be done as a branch in a fork like normal.) So here we are removing:
* the configure option
* the macro
* the code enabled by the macro
Added a new stable API function ``PyType_FromMetaclass``, which mirrors
the behavior of ``PyType_FromModuleAndSpec`` except that it takes an
additional metaclass argument. This is, e.g., useful for language
binding tools that need to store additional information in the type
object.
Replace "(PyCFunction)(void(*)(void))func" cast with
_PyCFunction_CAST(func).
Change generated by the command:
sed -i -e \
's!(PyCFunction)(void(\*)(void)) *\([A-Za-z0-9_]\+\)!_PyCFunction_CAST(\1)!g' \
$(find -name "*.c")
Copying and pickling instances of subclasses of builtin types
bytearray, set, frozenset, collections.OrderedDict, collections.deque,
weakref.WeakSet, and datetime.tzinfo now copies and pickles instance attributes
implemented as slots.
Add macros to cast objects to PyASCIIObject*, PyCompactUnicodeObject*
and PyUnicodeObject*: _PyASCIIObject_CAST(),
_PyCompactUnicodeObject_CAST() and _PyUnicodeObject_CAST(). Using
these new macros make the code more readable and check their argument
with: assert(PyUnicode_Check(op)).
Remove redundant assert(PyUnicode_Check(op)) in macros using directly
or indirectly these new CAST macros.
Replacing existing casts with these macros.
* Moves the bytecode to the end of the corresponding PyCodeObject, and quickens it in-place.
* Removes the almost-always-unused co_varnames, co_freevars, and co_cellvars member caches
* _PyOpcode_Deopt is a new mapping from all opcodes to their un-quickened forms.
* _PyOpcode_InlineCacheEntries is renamed to _PyOpcode_Caches
* _Py_IncrementCountAndMaybeQuicken is renamed to _PyCode_Warmup
* _Py_Quicken is renamed to _PyCode_Quicken
* _co_quickened is renamed to _co_code_adaptive (and is now a read-only memoryview).
* Do not emit unused nonzero opargs anymore in the compiler.
Instead of manually enumerating the global strings in generate_global_objects.py, we extrapolate the list from usage of _Py_ID() and _Py_STR() in the source files.
This is partly inspired by gh-31261.
https://bugs.python.org/issue46541
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
Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the
public C API by mistake, it must only be used by Python internally.
Use the PyTypeObject.tp_members member instead.
Rename PyHeapType_GET_MEMBERS() to _PyHeapType_GET_MEMBERS() and move
it to the internal C API.
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 comment to recurse_down_subclasses() explaining why it's safe
to use a borrowed reference to tp_subclasses.
* remove_all_subclasses() no longer accept NULL cases
* type_set_bases() now relies on the fact that new_bases is not NULL.
* type_dealloc_common() avoids PyErr_Fetch/PyErr_Restore if tp_bases
is NULL.
* remove_all_subclasses() makes sure that no exception is raised.
* Don't test at runtime if tp_mro only contains types: rely on
_PyType_CAST() assertion for that.
* _PyStaticType_Dealloc() no longer clears tp_subclasses which is
already NULL.
* mro_hierarchy() avoids calling _PyType_GetSubclasses() if
tp_subclasses is NULL.
Coding style:
* Use Py_NewRef().
* Add braces and move variable declarations to the first variable
assignement.
* Rename a few variables and parameters to use better names.
The remove_subclass() function now deletes the dictionary when
removing the last subclass (if the dictionary becomes empty) to save
memory: set PyTypeObject.tp_subclasses to NULL. remove_subclass() is
called when a type is deallocated.
_PyType_GetSubclasses() no longer holds a reference to tp_subclasses:
its loop cannot modify tp_subclasses.
Fix a race condition on setting a type __bases__ attribute: the
internal function add_subclass() now gets the
PyTypeObject.tp_subclasses member after calling PyWeakref_NewRef()
which can trigger a garbage collection which can indirectly modify
PyTypeObject.tp_subclasses.
Add a new _PyType_GetSubclasses() function to get type's subclasses.
_PyType_GetSubclasses(type) returns a list which holds strong
refererences to subclasses. It is safer than iterating on
type->tp_subclasses which yields weak references and can be modified
in the loop.
_PyType_GetSubclasses(type) now holds a reference to the tp_subclasses
dict while creating the list of subclasses.
set_collection_flag_recursive() of _abc.c now uses
_PyType_GetSubclasses().
Add _PyTypes_FiniTypes() best-effort function to clear static types:
don't deallocate a type if it still has subclasses.
remove_subclass() now sets tp_subclasses to NULL when removing the
last subclass.
