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.
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.
⚠️⚠️ Note for reviewers, hackers and fellow systems/low-level/compiler engineers ⚠️⚠️
If you have a lot of experience with this kind of shenanigans and want to improve the **first** version, **please make a PR against my branch** or **reach out by email** or **suggest code changes directly on GitHub**.
If you have any **refinements or optimizations** please, wait until the first version is merged before starting hacking or proposing those so we can keep this PR productive.
* gh-93503: Add APIs to set profiling and tracing functions in all threads in the C-API
* Use a separate API
* Fix NEWS entry
* Add locks around the loop
* Document ignoring exceptions
* Use the new APIs in the sys module
* Update docs
We only statically initialize for core code and builtin modules. Extension modules still create
the tuple at runtime. We'll solve that part of interpreter isolation separately.
This change includes generated code. The non-generated changes are in:
* Tools/clinic/clinic.py
* Python/getargs.c
* Include/cpython/modsupport.h
* Makefile.pre.in (re-generate global strings after running clinic)
* very minor tweaks to Modules/_codecsmodule.c and Python/Python-tokenize.c
All other changes are generated code (clinic, global strings).
* Add co_firstinstr field to code object.
* Implement barebones quickening.
* Use non-quickened bytecode when tracing.
* Add NEWS item
* Add new file to Windows build.
* Don't specialize instructions with EXTENDED_ARG.
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.
In ArgumentClinic, value "NULL" should now be used only for unrepresentable default values
(like in the optional third parameter of getattr). "None" should be used if None is accepted
as argument and passing None has the same effect as not passing the argument at all.
Remove the undocumented sys.callstats() function. Since Python 3.7,
it was deprecated and always returned None. It required a special
build option CALL_PROFILE which was already removed in Python 3.7.
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.
It has been documented as deprecated and to be removed in 3.8;
From a comment on another thread – which I can't find ; leave get_coro_wrapper() for now, but always return `None`.
https://bugs.python.org/issue36933
* sys.unraisablehook: add 'err_msg' field to UnraisableHookArgs.
* Use _PyErr_WriteUnraisableMsg() in _ctypes _DictRemover_call()
and gc delete_garbage().
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
Use _PyArg_CheckPositional() and inlined code instead of
PyArg_UnpackTuple() and _PyArg_UnpackStack() if all parameters
are positional and use the "object" converter.
Fix invalid function cast warnings with gcc 8
for method conventions different from METH_NOARGS, METH_O and
METH_VARARGS in Argument Clinic generated code.
* Add coro.cr_origin and sys.set_coroutine_origin_tracking_depth
* Use coroutine origin information in the unawaited coroutine warning
* Stop using set_coroutine_wrapper in asyncio debug mode
* In BaseEventLoop.set_debug, enable debugging in the correct thread
Victor Stinner
Eddie Elizondo
Steve Dower
Jeremy Paige
Brandt Bucher
Erlend E. Aasland
Gregory P. Smith
Pablo Galindo Salgado
Eric Snow
Mark Shannon
Irit Katriel
Julien Danjou
Serhiy Storchaka
Rémi Lapeyre
Raymond Hettinger
Victor Stinner
Matthias Bussonnier
Steve Dower
Tal Einat
Nathaniel J. Smith