This is the implementation of PEP683
Motivation:
The PR introduces the ability to immortalize instances in CPython which bypasses reference counting. Tagging objects as immortal allows up to skip certain operations when we know that the object will be around for the entire execution of the runtime.
Note that this by itself will bring a performance regression to the runtime due to the extra reference count checks. However, this brings the ability of having truly immutable objects that are useful in other contexts such as immutable data sharing between sub-interpreters.
* The majority of the monitoring code is in instrumentation.c
* The new instrumentation bytecodes are in bytecodes.c
* legacy_tracing.c adapts the new API to the old sys.setrace and sys.setprofile APIs
* Don't deadlock on shutdown if test_current_{exception,frames} fails
These tests spawn a thread that waits on a threading.Event. If the test fails any of its assertions, the Event won't be signaled and the thread will wait indefinitely, causing a deadlock when threading._shutdown() tries to join all outstanding threads.
Co-authored-by: Brett Simmers <bsimmers@meta.com>
* Add a news entry
* Fix whitespace
---------
Co-authored-by: Brett Simmers <bsimmers@meta.com>
Co-authored-by: Oleg Iarygin <oleg@arhadthedev.net>
Fixes behaviour where int (and subtypes like bool) __sizeof__ under-reports true size as it did not take into account the size 1 `ob_digit` array for the zero int.
Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
Integer to and from text conversions via CPython's bignum `int` type is not safe against denial of service attacks due to malicious input. Very large input strings with hundred thousands of digits can consume several CPU seconds.
This PR comes fresh from a pile of work done in our private PSRT security response team repo.
Signed-off-by: Christian Heimes [Red Hat] <christian@python.org>
Tons-of-polishing-up-by: Gregory P. Smith [Google] <greg@krypto.org>
Reviews via the private PSRT repo via many others (see the NEWS entry in the PR).
<!-- gh-issue-number: gh-95778 -->
* Issue: gh-95778
<!-- /gh-issue-number -->
I wrote up [a one pager for the release managers](https://docs.google.com/document/d/1KjuF_aXlzPUxTK4BMgezGJ2Pn7uevfX7g0_mvgHlL7Y/edit#). Much of that text wound up in the Issue. Backports PRs already exist. See the issue for links.
* Make sure that tp_dictoffset is correct with Py_TPFLAGS_MANAGED_DICT is set.
* Avoid traversing managed dict twice when subclassing class with Py_TPFLAGS_MANAGED_DICT set.
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.
Add the -P command line option and the PYTHONSAFEPATH environment
variable to not prepend a potentially unsafe path to sys.path.
* Add sys.flags.safe_path flag.
* Add PyConfig.safe_path member.
* Programs/_bootstrap_python.c uses config.safe_path=0.
* Update subprocess._optim_args_from_interpreter_flags() to handle
the -P command line option.
* Modules/getpath.py sets safe_path to 1 if a "._pth" file is
present.
* Add RETURN_GENERATOR and JUMP_NO_INTERRUPT opcodes.
* Trim frame and generator by word each.
* Minor refactor of frame.c
* Update test.test_sys to account for smaller frames.
* Treat generator functions as normal functions when evaluating and specializing.
* Do not PUSH/POP traceback or type to the stack as part of exc_info
* Remove exc_traceback and exc_type from _PyErr_StackItem
* Add to what's new, because this change breaks things like Cython
* Make generator, coroutine and async gen structs all the same size.
* Store interpreter frame in generator (and coroutine). Reduces the number of allocations neeeded for a generator from two to one.
Freelists for object structs can now be disabled. A new ``configure``
option ``--without-freelists`` can be used to disable all freelists
except empty tuple singleton. Internal Py*_MAXFREELIST macros can now
be defined as 0 without causing compiler warnings and segfaults.
Signed-off-by: Christian Heimes <christian@python.org>
* Never change types' cached keys. It could invalidate inline attribute objects.
* Lazily create object dictionaries.
* Update specialization of LOAD/STORE_ATTR.
* Don't update shared keys version for deletion of value.
* Update gdb support to handle instance values.
* Rename SPLIT_KEYS opcodes to INSTANCE_VALUE.
During runtime startup we figure out the stdlib dir but currently throw that information away. This change preserves it and exposes it via PyConfig.stdlib_dir, _Py_GetStdlibDir(), and sys._stdlib_dir.
https://bugs.python.org/issue45211
* Convert "specials" array to InterpreterFrame struct, adding f_lasti, f_state and other non-debug FrameObject fields to it.
* Refactor, calls pushing the call to the interpreter upward toward _PyEval_Vector.
* Compute f_back when on thread stack, only filling in value when frame object outlives stack invocation.
* Move ownership of InterpreterFrame in generator from frame object to generator object.
* Do not create frame objects for Python calls.
* Do not create frame objects for generators.
* Remove 'zombie' frames. We won't need them once we are allocating fixed-size frames.
* Add co_nlocalplus field to code object to avoid recomputing size of locals + frees + cells.
* Move locals, cells and freevars out of frame object into separate memory buffer.
* Use per-threadstate allocated memory chunks for local variables.
* Move globals and builtins from frame object to per-thread stack.
* Move (slow) locals frame object to per-thread stack.
* Move internal frame functions to internal header.
"Zero cost" exception handling.
* Uses a lookup table to determine how to handle exceptions.
* Removes SETUP_FINALLY and POP_TOP block instructions, eliminating (most of) the runtime overhead of try statements.
* Reduces the size of the frame object by about 60%.
Add a new Py_TPFLAGS_DISALLOW_INSTANTIATION type flag to disallow
creating type instances: set tp_new to NULL and don't create the
"__new__" key in the type dictionary.
The flag is set automatically on static types if tp_base is NULL or
&PyBaseObject_Type and tp_new is NULL.
Use the flag on the following types:
* _curses.ncurses_version type
* _curses_panel.panel
* _tkinter.Tcl_Obj
* _tkinter.tkapp
* _tkinter.tktimertoken
* _xxsubinterpretersmodule.ChannelID
* sys.flags type
* sys.getwindowsversion() type
* sys.version_info type
Update MyStr example in the C API documentation to use
Py_TPFLAGS_DISALLOW_INSTANTIATION.
Add _PyStructSequence_InitType() function to create a structseq type
with the Py_TPFLAGS_DISALLOW_INSTANTIATION flag set.
type_new() calls _PyType_CheckConsistency() at exit.
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
This adds a new function named sys._current_exceptions() which is equivalent ot
sys._current_frames() except that it returns the exceptions currently handled
by other threads. It is equivalent to calling sys.exc_info() for each running
thread.
* Merge gen and frame state variables into one.
* Replace stack pointer with depth in PyFrameObject. Makes code easier to read and saves a word of memory.
Add sys.orig_argv attribute: the list of the original command line
arguments passed to the Python executable.
Rename also PyConfig._orig_argv to PyConfig.orig_argv and
document it.
Followup of bpo-40854, there is one remaining usage of PLATLIBDIR
which should be replaced by config->platlibdir.
test_sys checks that sys.platlibdir attribute exists and is a string.
Update Makefile: getpath.c and sysmodule.c no longer need PLATLIBDIR
macro, PyConfig.platlibdir member is used instead.
Co-authored-by: Sandro Mani <manisandro@gmail.com>
Module C state is now accessible from C-defined heap type methods (PEP 573).
Patch by Marcel Plch and Petr Viktorin.
Co-authored-by: Marcel Plch <mplch@redhat.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
* Rename PyConfig.use_peg to _use_peg_parser
* Document PyConfig._use_peg_parser and mark it a deprecated
* Mark -X oldparser option and PYTHONOLDPARSER env var as deprecated
in the documentation.
* Add use_old_parser() and skip_if_new_parser() to test.support
* Remove sys.flags.use_peg: use_old_parser() uses
_testinternalcapi.get_configs() instead.
* Enhance test_embed tests
* subprocess._args_from_interpreter_flags() copies -X oldparser
Move the PyGC_Head structure and the following private macros to the
internal C API:
* _PyGCHead_FINALIZED()
* _PyGCHead_NEXT()
* _PyGCHead_PREV()
* _PyGCHead_SET_FINALIZED()
* _PyGCHead_SET_NEXT()
* _PyGCHead_SET_PREV()
* _PyGC_FINALIZED()
* _PyGC_PREV_MASK
* _PyGC_PREV_MASK_COLLECTING
* _PyGC_PREV_MASK_FINALIZED
* _PyGC_PREV_SHIFT
* _PyGC_SET_FINALIZED()
* _PyObject_GC_IS_TRACKED()
* _PyObject_GC_MAY_BE_TRACKED()
* _Py_AS_GC(o)
Keep the private _PyGC_FINALIZED() macro in the public C API for
backward compatibility with Python 3.8: make it an alias to the new
PyObject_GC_IsFinalized() function.
Move the SIZEOF_PYGC_HEAD constant from _testcapi module to
_testinternalcapi module.
The Py_FatalError() function is replaced with a macro which logs
automatically the name of the current function, unless the
Py_LIMITED_API macro is defined.
Changes:
* Add _Py_FatalErrorFunc() function.
* Remove the function name from the message of Py_FatalError() calls
which included the function name.
* Update tests.
Currently, during runtime destruction, `_PyImport_Cleanup` is clearing the interpreter state before clearing out the modules themselves. This leads to a segfault on modules that rely on the module state to clear themselves up.
For example, let's take the small snippet added in the issue by @DinoV :
```
import _struct
class C:
def __init__(self):
self.pack = _struct.pack
def __del__(self):
self.pack('I', -42)
_struct.x = C()
```
The module `_struct` uses the module state to run `pack`. Therefore, the module state has to be alive until after the module has been cleared out to successfully run `C.__del__`. This happens at line 606, when `_PyImport_Cleanup` calls `_PyModule_Clear`. In fact, the loop that calls `_PyModule_Clear` has in its comments:
> Now, if there are any modules left alive, clear their globals to minimize potential leaks. All C extension modules actually end up here, since they are kept alive in the interpreter state.
That means that we can't clear the module state (which is used by C Extensions) before we run that loop.
Moving `_PyInterpreterState_ClearModules` until after it, fixes the segfault in the code snippet.
Finally, this updates a test in `io` to correctly assert the error that it now throws (since it now finds the io module state). The test that uses this is: `test_create_at_shutdown_without_encoding`. Given this test is now working is a proof that the module state now stays alive even when `__del__` is called at module destruction time. Thus, I didn't add a new tests for this.
https://bugs.python.org/issue38076
Fix sys.excepthook() and PyErr_Display() if a filename is a bytes
string. For example, for a SyntaxError exception where the filename
attribute is a bytes string.
Cleanup also test_sys:
* Sort imports.
* Rename numruns global var to INTERN_NUMRUNS.
* Add DisplayHookTest and ExceptHookTest test case classes.
* Don't save/restore sys.stdout and sys.displayhook using
setUp()/tearDown(): do it in each test method.
* Test error case (call hook with no argument) after the success case.
Remove sys.getcheckinterval() and sys.setcheckinterval() functions.
They were deprecated since Python 3.2. Use sys.getswitchinterval()
and sys.setswitchinterval() instead.
Remove also check_interval field of the PyInterpreterState structure.
* sys.unraisablehook: add 'err_msg' field to UnraisableHookArgs.
* Use _PyErr_WriteUnraisableMsg() in _ctypes _DictRemover_call()
and gc delete_garbage().
PyErr_WriteUnraisable() now creates a traceback object if there is no
current traceback. Moreover, call PyErr_NormalizeException() and
PyException_SetTraceback() to normalize the exception value. Ignore
silently any error.
* Copy test_exceptions.test_unraisable() to
test_sys.UnraisableHookTest().
* Use catch_unraisable_exception() in test_coroutines,
test_exceptions, test_generators.
Add new sys.unraisablehook() function which can be overridden to
control how "unraisable exceptions" are handled. It is called when an
exception has occurred but there is no way for Python to handle it.
For example, when a destructor raises an exception or during garbage
collection (gc.collect()).
Changes:
* Add an internal UnraisableHookArgs type used to pass arguments to
sys.unraisablehook.
* Add _PyErr_WriteUnraisableDefaultHook().
* The default hook now ignores exception on writing the traceback.
* test_sys now uses unittest.main() to automatically discover tests:
remove test_main().
* Add _PyErr_Init().
* Fix PyErr_WriteUnraisable(): hold a strong reference to sys.stderr
while using it
Fix test_sys.test_getallocatedblocks() when tracemalloc is enabled.
If the name of Python memory allocators cannot get read, consider
that pymalloc is disabled.
Fix the following error:
./python -X tracemalloc -m test test_sys -v -m test_getallocatedblocks
ERROR: test_getallocatedblocks (test.test_sys.SysModuleTest)
------------------------------------------------------------
Traceback (most recent call last):
File "Lib/test/test_sys.py", line 770, in test_getallocatedblocks
alloc_name = _testcapi.pymem_getallocatorsname()
RuntimeError: cannot get allocators name
* Revert "bpo-34589: Add -X coerce_c_locale command line option (GH-9378)"
This reverts commit dbdee0073c.
* Revert "bpo-34589: C locale coercion off by default (GH-9073)"
This reverts commit 7a0791b699.
* Revert "bpo-34589: Make _PyCoreConfig.coerce_c_locale private (GH-9371)"
This reverts commit 188ebfa475.
_PyCoreConfig_Read() is now responsible to choose the filesystem
encoding and error handler. Using Py_Main(), the encoding is now
chosen even before calling Py_Initialize().
_PyCoreConfig.filesystem_encoding is now the reference, instead of
Py_FileSystemDefaultEncoding, for the Python filesystem encoding.
Changes:
* Add filesystem_encoding and filesystem_errors to _PyCoreConfig
* _PyCoreConfig_Read() now reads the locale encoding for the file
system encoding.
* PyUnicode_EncodeFSDefault() and PyUnicode_DecodeFSDefaultAndSize()
now use the interpreter configuration rather than
Py_FileSystemDefaultEncoding and Py_FileSystemDefaultEncodeErrors
global configuration variables.
* Add _Py_SetFileSystemEncoding() and _Py_ClearFileSystemEncoding()
private functions to only modify Py_FileSystemDefaultEncoding and
Py_FileSystemDefaultEncodeErrors in coreconfig.c.
* _Py_CoerceLegacyLocale() now takes an int rather than
_PyCoreConfig for the warning.
Standard streams like sys.stdout now use the "surrogateescape" error
handler, instead of "strict", on the POSIX locale (when the C locale is not
coerced and the UTF-8 Mode is disabled).
Add tests on sys.stdout.errors with LC_ALL=POSIX.
Python now gets the locale encoding with C code to initialize the encoding
of standard streams like sys.stdout. Moreover, the encoding is now
initialized to the Python codec name to get a normalized encoding name and
to ensure that the codec is loaded. The change avoids importing
_bootlocale and _locale modules at startup by default.
When the PYTHONIOENCODING environment variable only contains an encoding,
the error handler is now is now set explicitly to "strict".
Rename also get_default_standard_stream_error_handler() to
get_stdio_errors().
Reduce the buffer to format the "cpXXX" string (Windows locale encoding).
External importers were being added in both phases of the import
system initialisation.
They're only supposed to be added in the second phase, after the
import machinery has been appropriately configured.
* Add -X utf8 command line option, PYTHONUTF8 environment variable
and a new sys.flags.utf8_mode flag.
* If the LC_CTYPE locale is "C" at startup: enable automatically the
UTF-8 mode.
* Add _winapi.GetACP(). encodings._alias_mbcs() now calls
_winapi.GetACP() to get the ANSI code page
* locale.getpreferredencoding() now returns 'UTF-8' in the UTF-8
mode. As a side effect, open() now uses the UTF-8 encoding by
default in this mode.
* Py_DecodeLocale() and Py_EncodeLocale() now use the UTF-8 encoding
in the UTF-8 Mode.
* Update subprocess._args_from_interpreter_flags() to handle -X utf8
* Skip some tests relying on the current locale if the UTF-8 mode is
enabled.
* Add test_utf8mode.py.
* _Py_DecodeUTF8_surrogateescape() gets a new optional parameter to
return also the length (number of wide characters).
* pymain_get_global_config() and pymain_set_global_config() now
always copy flag values, rather than only copying if the new value
is greater than the old value.
* bpo-32101: Add sys.flags.dev_mode flag
Rename also the "Developer mode" to the "Development mode".
* bpo-32101: Add PYTHONDEVMODE environment variable
Mention it in the development chapiter.
* Fix _PyMem_SetupAllocators("debug"): always restore allocators to
the defaults, rather than only caling _PyMem_SetupDebugHooks().
* Add _PyMem_SetDefaultAllocator() helper to set the "default"
allocator.
* Add _PyMem_GetAllocatorsName(): get the name of the allocators
* main() now uses debug hooks on memory allocators if Py_DEBUG is
defined, rather than calling directly malloc()
* Document default memory allocators in C API documentation
* _Py_InitializeCore() now fails with a fatal user error if
PYTHONMALLOC value is an unknown memory allocator, instead of
failing with a fatal internal error.
* Add new tests on the PYTHONMALLOC environment variable
* Add support.with_pymalloc()
* Add the _testcapi.WITH_PYMALLOC constant and expose it as
support.with_pymalloc().
* sysconfig.get_config_var('WITH_PYMALLOC') doesn't work on Windows, so
replace it with support.with_pymalloc().
* pythoninfo: add _testcapi collector for pymem
Eddie Elizondo