While working on another issue, I noticed two minor nits in the C implementation of the module object. Both are related to getting a module's name.
First, the C function module_dir() (module.__dir__) starts by ensuring the module dict is valid. If the module dict is invalid, it wants to format an exception using the name of the module, which it gets from PyModule_GetName(). However, PyModule_GetName() gets the name of the module from the dict. So getting the name in this circumstance will never succeed.
When module_dir() wants to format the error but can't get the name, it knows that PyModule_GetName() must have already raised an exception. So it leaves that exception alone and returns an error. The end result is that the exception raised here is kind of useless and misleading: dir(module) on a module with no __dict__ raises SystemError("nameless module"). I changed the code to actually raise the exception it wanted to raise, just without a real module name: TypeError("<module>.__dict__ is not a dictionary"). This seems more useful, and would do a better job putting the programmer who encountered this on the right track of figuring out what was going on.
Second, the C API function PyModule_GetNameObject() checks to see if the module has a dict. If m->md_dict is not NULL, it calls _PyDict_GetItemIdWithError(). However, it's possible for m->md_dict to be None. And if you call _PyDict_GetItemIdWithError(Py_None, ...) it will *crash*.
Unfortunately, this crash was due to my own bug in the other branch. Fixing my code made the crash go away. I assert that this is still possible at the API level.
The fix is easy: add a PyDict_Check() to PyModule_GetNameObject().
Unfortunately, I don't know how to add a unit test for this. Having changed module_dir() above, I can't find any other interfaces callable from Python that eventually call PyModule_GetNameObject(). So I don't know how to trick the runtime into reproducing this error.
Since both these changes are minor--each entails only a small edit to only one line--I didn't bother with a news item.
Change class and module objects to lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object's `__dict__` for backwards compatibility.
Accessing the following attributes will now fire PEP 578 style audit hooks as ("object.__getattr__", obj, name):
* PyTracebackObject: tb_frame
* PyFrameObject: f_code
* PyGenObject: gi_code, gi_frame
* PyCoroObject: cr_code, cr_frame
* PyAsyncGenObject: ag_code, ag_frame
Add an AUDIT_READ attribute flag aliased to READ_RESTRICTED.
Update obsolete flag documentation.
* Add length parameter to PyLineTable_InitAddressRange and doen't use sentinel values at end of table. Makes the line number table more robust.
* Update PyCodeAddressRange to match PEP 626.
Introduce Py_TPFLAGS_IMMUTABLETYPE flag for immutable type objects, and
modify PyType_Ready() to set it for static types.
Co-authored-by: Victor Stinner <vstinner@python.org>
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
Add pycore_moduleobject.h internal header file with static inline
functions to access module members:
* _PyModule_GetDict()
* _PyModule_GetDef()
* _PyModule_GetState()
These functions don't check at runtime if their argument has a valid
type and can be inlined even if Python is not built with LTO.
_PyType_GetModuleByDef() uses _PyModule_GetDef().
Replace PyModule_GetState() with _PyModule_GetState() in the
extension modules, considered as performance sensitive:
* _abc
* _functools
* _operator
* _pickle
* _queue
* _random
* _sre
* _struct
* _thread
* _winapi
* array
* posix
The following extensions are now built with the Py_BUILD_CORE_MODULE
macro defined, to be able to use the internal pycore_moduleobject.h
header: _abc, array, _operator, _queue, _sre, _struct.
PyType_Ready() now ensures that a type MRO cannot be empty.
_PyType_GetModuleByDef() no longer checks "i < PyTuple_GET_SIZE(mro)"
at the first loop iteration to optimize the most common case, when
the argument is the defining class.
_PyType_GetModuleByDef() no longer checks if types are heap types.
_PyType_GetModuleByDef() must only be called on a heap type created
by PyType_FromModuleAndSpec() or on its subclasses.
type_ready_mro() ensures that a static type cannot inherit from a
heap type.
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?
* Rename functions
* Only pass type parameter to "add_xxx" functions.
* Clarify the role of the type_ready_inherit_as_structs() function.
* Move type_dict_set_doc() code to call it in type_ready_fill_dict().
* Split PyType_Ready() into sub-functions.
* type_ready_mro() now checks if bases are static types earlier.
* Check tp_name earlier, in type_ready_checks().
* Add _PyType_IsReady() macro to check if a type is ready.
Add the Py_Is(x, y) function to test if the 'x' object is the 'y'
object, the same as "x is y" in Python. Add also the Py_IsNone(),
Py_IsTrue(), Py_IsFalse() functions to test if an object is,
respectively, the None singleton, the True singleton or the False
singleton.
* Split type_new() into into many small functions.
* Add type_new_ctx structure to pass variables between subfunctions.
* Initialize some PyTypeObject and PyHeapTypeObject members earlier
in type_new_alloc().
* Rename variables to more specific names.
* Add "__weakref__" identifier for type_new_visit_slots().
* Factorize code to convert a method to a classmethod
(__init_subclass__ and __class_getitem__).
* Add braces to respect PEP 7.
* Move variable declarations where the variables are initialized.
Static methods (@staticmethod) and class methods (@classmethod) now
inherit the method attributes (__module__, __name__, __qualname__,
__doc__, __annotations__) and have a new __wrapped__ attribute.
Changes:
* Add a repr() method to staticmethod and classmethod types.
* Add tests on the @classmethod decorator.
* Handle check for sending None to starting generator and coroutine into bytecode.
* Document new bytecode and make it fail gracefully if mis-compiled.
The limited C API is now supported if Python is built in debug mode
(if the Py_DEBUG macro is defined). In the limited C API, the
Py_INCREF() and Py_DECREF() functions are now implemented as opaque
function calls, rather than accessing directly the PyObject.ob_refcnt
member, if Python is built in debug mode and the Py_LIMITED_API macro
targets Python 3.10 or newer. It became possible to support the
limited C API in debug mode because the PyObject structure is the
same in release and debug mode since Python 3.8 (see bpo-36465).
The limited C API is still not supported in the --with-trace-refs
special build (Py_TRACE_REFS macro).
Reorganize pycore_interp_init() to initialize singletons before the
the first PyType_Ready() call. Fix an issue when Python is configured
using --without-doc-strings.
* Use instruction offset, rather than bytecode offset. Streamlines interpreter dispatch a bit, and removes most EXTENDED_ARGs for jumps.
* Change some uses of PyCode_Addr2Line to PyFrame_GetLineNumber
When printing stats, move radix tree info to its own section.
Restore that the breakdown of bytes in arenas exactly accounts for the total of arena bytes allocated.
Add an assert so that invariant doesn't break again.
* Remove m68k-specific hack from ascii_decode
On m68k, alignments of primitives is more relaxed, with 4-byte and
8-byte types only requiring 2-byte alignment, thus using sizeof(size_t)
does not work. Instead, use the portable alternative.
Note that this is a minimal fix that only relaxes the assertion and the
condition for when to use the optimised version remains overly strict.
Such issues will be fixed tree-wide in the next commit.
NB: In C11 we could use _Alignof(size_t) instead, but for compatibility
we use autoconf.
* Optimise string routines for architectures with non-natural alignment
C only requires that sizeof(x) is a multiple of alignof(x), not that the
two are equal. Thus anywhere where we optimise based on alignment we
should be using alignof(x) not sizeof(x).
This is more annoying than it would be in C11 where we could just use
_Alignof(x) (and alignof(x) in C++11), but since we still require only
C99 we must plumb the information all the way from autoconf through the
various typedefs and defines.
The radix tree approach is a relatively simple and memory sanitary
alternative to the old (slightly) unsanitary address_in_range().
To disable the radix tree map, set a preprocessor flag as follows:
-DWITH_PYMALLOC_RADIX_TREE=0.
Co-authored-by: Tim Peters <tim.peters@gmail.com>
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
Remove the compiler functions using "struct _mod" type, because the
public AST C API was removed:
* PyAST_Compile()
* PyAST_CompileEx()
* PyAST_CompileObject()
* PyFuture_FromAST()
* PyFuture_FromASTObject()
These functions were undocumented and excluded from the limited C API.
Rename functions:
* PyAST_CompileObject() => _PyAST_Compile()
* PyFuture_FromASTObject() => _PyFuture_FromAST()
Moreover, _PyFuture_FromAST() is no longer exported (replace
PyAPI_FUNC() with extern). _PyAST_Compile() remains exported for
test_peg_generator.
Remove also compatibility functions:
* PyAST_Compile()
* PyAST_CompileEx()
* PyFuture_FromAST()
The common case going through _PyType_Lookup is to have a cache hit. There are some small tweaks that can make this a little cheaper:
* The name field identity is used for a cache hit and is kept alive by the cache. So there's no need to read the hash code o the name - instead, the address can be used as the hash.
* There's no need to check if the name is cachable on the lookup either, it probably is, and if it is, it'll be in the cache.
* If we clear the version tag when invalidating a type then we don't actually need to check for a valid version tag bit.
* Remove an assertion which required CO_NEWLOCALS and CO_OPTIMIZED
code flags. It is ok to call this function on a code with these
flags set.
* Fix reference counting on builtins: remove Py_DECREF().
Fix regression introduced in the
commit 46496f9d12.
Add also a comment to document that _PyEval_BuiltinsFromGlobals()
returns a borrowed reference.
Python no longer fails at startup with a fatal error if a command
line argument contains an invalid Unicode character.
The Py_DecodeLocale() function now escapes byte sequences which would
be decoded as Unicode characters outside the [U+0000; U+10ffff]
range.
Use MAX_UNICODE constant in unicodeobject.c.
Implement an enhanced variant of Crochemore and Perrin's Two-Way string searching algorithm, which reduces worst-case time from quadratic (the product of the string and pattern lengths) to linear. This applies to forward searches (like``find``, ``index``, ``replace``); the algorithm for reverse searches (like ``rfind``) is not changed.
Co-authored-by: Tim Peters <tim.peters@gmail.com>
larryhastings
Steve Dower
Ryan Hileman
Mark Shannon
Hristo Venev
Erlend Egeberg Aasland
Ken Jin
Victor Stinner
Pablo Galindo
Raymond Hettinger
Dennis Sweeney
Tim Peters
Jessica Clarke
Neil Schemenauer
Inada Naoki
Joshua Bronson
Dino Viehland
Skip Montanaro
junyixie
Jozef Grajciar