This fixes a crasher due to a race condition, triggered infrequently when two isolated (own GIL) subinterpreters simultaneously initialize their sys or builtins modules. The crash happened due the combination of the "detached" thread state we were using and the "last holder" logic we use for the GIL. It turns out it's tricky to use the same thread state for different threads. Who could have guessed?
We solve the problem by eliminating the one object we were still sharing between interpreters. We replace it with a low-level hashtable, using the "raw" allocator to avoid tying it to the main interpreter.
We also remove the accommodations for "detached" thread states, which were a dubious idea to start with.
The _xxsubinterpreters module should not rely on internal API. Some of the functions it uses were recently moved there however. Here we move them back (and expose them properly).
We tried this before with a dict and for all interned strings. That ran into problems due to interpreter isolation. However, exclusively using a per-interpreter cache caused some inconsistency that can eliminate the benefit of interning. Here we circle back to using a global cache, but only for statically allocated strings. We also use a more-basic _Py_hashtable_t for that global cache instead of a dict.
Ideally we would only have the global cache, but the optional isolation of each interpreter's allocator means that a non-static string object must not outlive its interpreter. Thus we would have to store a copy of each such interned string in the global cache, tied to the main interpreter.
Fix warnings C4100 in Py_UNUSED() when Python is built with "cl /W4".
Example with this function included by Python.h:
static inline unsigned int
PyUnicode_IS_READY(PyObject* Py_UNUSED(op))
{ return 1; }
Without this change, building a C program with "cl /W4" which just
includes Python.h emits the warning:
Include\cpython/unicodeobject.h(199):
warning C4100: '_unused_op': unreferenced formal parameter
This change fix this warning.
No longer export these 5 internal C API variables:
* _PyBufferWrapper_Type
* _PyImport_FrozenBootstrap
* _PyImport_FrozenStdlib
* _PyImport_FrozenTest
* _Py_SwappedOp
Fix the definition of these internal functions, replace PyAPI_DATA()
with PyAPI_FUNC():
* _PyImport_ClearExtension()
* _PyObject_IsFreed()
* _PyThreadState_GetCurrent()
No longer export these 2 internal C API functions:
* _PyEval_SignalAsyncExc()
* _PyEval_SignalReceived()
Add also comments explaining why some internal functions have to be
exported, and update existing comments.
Move PyInterpreterConfig structure and associated macros from
initconfig.h to pylifecycle.h: it's not related to the Python
Initialization Configuration.
Declare the following 3 PyUnstable functions in
Include/cpython/pyframe.h rather than Include/cpython/frameobject.h,
so they are now provided by the standard "#include <Python.h>".
Move private _PyMem functions to the internal C API (pycore_pymem.h):
* _PyMem_GetCurrentAllocatorName()
* _PyMem_RawStrdup()
* _PyMem_RawWcsdup()
* _PyMem_Strdup()
No longer export these functions.
Move pymem_getallocatorsname() function from _testcapi to _testinternalcapi,
since the API moved to the internal C API.
Move private _PyDict functions to the internal C API (pycore_dict.h):
* _PyDict_Contains_KnownHash()
* _PyDict_DebugMallocStats()
* _PyDict_DelItemIf()
* _PyDict_GetItemWithError()
* _PyDict_HasOnlyStringKeys()
* _PyDict_MaybeUntrack()
* _PyDict_MergeEx()
No longer export these functions.
Move private _PyObject and private _PyType functions to the internal
C API (pycore_object.h):
* _PyObject_GetMethod()
* _PyObject_IsAbstract()
* _PyObject_NextNotImplemented()
* _PyType_CalculateMetaclass()
* _PyType_GetDocFromInternalDoc()
* _PyType_GetTextSignatureFromInternalDoc()
No longer export these functions.
Move private _PyBytes functions to the internal C API
(pycore_bytesobject.h):
* _PyBytes_DecodeEscape()
* _PyBytes_FormatEx()
* _PyBytes_FromHex()
* _PyBytes_Join()
No longer export these functions.
Move private debug _PyObject functions to the internal C API
(pycore_object.h):
* _PyDebugAllocatorStats()
* _PyObject_CheckConsistency()
* _PyObject_DebugTypeStats()
* _PyObject_IsFreed()
No longer export most of these functions, except of
_PyObject_IsFreed().
Move test functions using _PyObject_IsFreed() from _testcapi to
_testinternalcapi. check_pyobject_is_freed() test no longer catch
_testcapi.error: the tested function cannot raise _testcapi.error.
Move private _PyModule API to the internal C API
(pycore_moduleobject.h):
* _PyModule_Clear()
* _PyModule_ClearDict()
* _PyModuleSpec_IsInitializing()
* _PyModule_IsExtension()
No longer export these functions.
Rename private C API constants:
* Rename PY_MONITORING_UNGROUPED_EVENTS to _PY_MONITORING_UNGROUPED_EVENTS
* Rename PY_MONITORING_EVENTS to _PY_MONITORING_EVENTS
Move the private _PyInterpreterID C API to the internal C API: add a
new pycore_interp_id.h header file.
Remove Include/interpreteridobject.h and
Include/cpython/interpreteridobject.h header files.
Move private _PyGen API to internal C API:
* _PyAsyncGenAThrow_Type
* _PyAsyncGenWrappedValue_Type
* _PyCoroWrapper_Type
* _PyGen_FetchStopIterationValue()
* _PyGen_Finalize()
* _PyGen_SetStopIterationValue()
No longer these symbols, except of the ones by the _asyncio shared
extensions.
* No longer export most private _PyHash symbols, only export the ones
which are needed by shared extensions.
* Modules/_xxtestfuzz/fuzzer.c now uses the internal C API.
Remove private _PyUnicode_AsString() alias to PyUnicode_AsUTF8(). It
was kept for backward compatibility with Python 3.0 - 3.2.
The PyUnicode_AsUTF8() is available since Python
3.3. The PyUnicode_AsUTF8String() function can be used to keep
compatibility with Python 3.2 and older.
* Add PyDict_GetItemRef() and PyDict_GetItemStringRef() functions.
Add these functions to the stable ABI version 3.13.
* Add unit tests on the PyDict C API in test_capi.
