This is a temporary solution. The full fix may involve serializing the traceback in some form.
(FYI, I merged this yesterday and the reverted it due to buildbot failures. See gh-110248.)
In a few places we switch to another interpreter without knowing if it has a thread state associated with the current thread. For the main interpreter there wasn't much of a problem, but for subinterpreters we were *mostly* okay re-using the tstate created with the interpreter (located via PyInterpreterState_ThreadHead()). There was a good chance that tstate wasn't actually in use by another thread.
However, there are no guarantees of that. Furthermore, re-using an already used tstate is currently fragile. To address this, now we create a new thread state in each of those places and use it.
One consequence of this change is that PyInterpreterState_ThreadHead() may not return NULL (though that won't happen for the main interpreter).
The existence of background threads running on a subinterpreter was preventing interpreters from getting properly destroyed, as well as impacting the ability to run the interpreter again. It also affected how we wait for non-daemon threads to finish.
We add PyInterpreterState.threads.main, with some internal C-API functions.
Remove _PyErr_ChainExceptions(), _PyErr_ChainExceptions1() and
_PyErr_SetFromPyStatus() functions from the public C API.
* Move the private _PyErr_ChainExceptions() and
_PyErr_ChainExceptions1() function to the internal C API
(pycore_pyerrors.h).
* Move the private _PyErr_SetFromPyStatus() to the internal C API
(pycore_initconfig.h).
* No longer export the _PyErr_ChainExceptions() function.
* Move run_in_subinterp_with_config() from _testcapi to
_testinternalcapi.
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).
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.
Remove private _PyThreadState and _PyInterpreterState C API
functions: move them to the internal C API (pycore_pystate.h and
pycore_interp.h). Don't export most of these functions anymore, but
still export functions used by tests.
Remove _PyThreadState_Prealloc() and _PyThreadState_Init() from the C
API, but keep it in the stable API.
The _xxsubinterpreters module was meant to only use public API. Some internal C-API usage snuck in over the last few years (e.g. gh-28969). This fixes that.
Here we are doing no more than adding the value for Py_mod_multiple_interpreters and using it for stdlib modules. We will start checking for it in gh-104206 (once PyInterpreterState.ceval.own_gil is added in gh-104204).
In preparation for a per-interpreter GIL, we add PyInterpreterState.ceval.gil, set it to the shared GIL for each interpreter, and use that rather than using _PyRuntime.ceval.gil directly. Note that _PyRuntime.ceval.gil is still the actual GIL.
We also expose PyInterpreterConfig. This is part of the PEP 684 (per-interpreter GIL) implementation. We will add docs as soon as we can.
FYI, I'm adding the new config field for per-interpreter GIL in gh-99114.
The function is like Py_AtExit() but for a single interpreter. This is a companion to the atexit module's register() function, taking a C callback instead of a Python one.
We also update the _xxinterpchannels module to use _Py_AtExit(), which is the motivating case. (This is inspired by pain points felt while working on gh-101660.)
Fix a (correct) warning about potential uses of uninitialized memory in
_xxsubinterpreter. Unlike newly allocated PyObject structs or global
structs, stack-allocated structs are not initialised, and a few places in
the code expect the _sharedexception struct data to be either NULL or
initialised.
Prior to this change, errors in _Py_NewInterpreterFromConfig() were always fatal. Instead, callers should be able to handle such errors and keep going. That's what this change supports. (This was an oversight in the original implementation of _Py_NewInterpreterFromConfig().) Note that the existing [fatal] behavior of the public Py_NewInterpreter() is preserved.
https://github.com/python/cpython/issues/98608
Replace "Py_XDECREF(var); var = NULL;" with "Py_CLEAR(var);".
Don't replace "Py_DECREF(var); var = NULL;" with "Py_CLEAR(var);". It
would add an useless "if (var)" test in code path where var cannot be
NULL.
Previously, the optional restrictions on subinterpreters were: disallow fork, subprocess, and threads. By default, we were disallowing all three for "isolated" interpreters. We always allowed all three for the main interpreter and those created through the legacy `Py_NewInterpreter()` API.
Those settings were a bit conservative, so here we've adjusted the optional restrictions to: fork, exec, threads, and daemon threads. The default for "isolated" interpreters disables fork, exec, and daemon threads. Regular threads are allowed by default. We continue always allowing everything For the main interpreter and the legacy API.
In the code, we add `_PyInterpreterConfig.allow_exec` and `_PyInterpreterConfig.allow_daemon_threads`. We also add `Py_RTFLAGS_DAEMON_THREADS` and `Py_RTFLAGS_EXEC`.
(see https://github.com/python/cpython/issues/98608)
This change does the following:
1. change the argument to a new `_PyInterpreterConfig` struct
2. rename the function to `_Py_NewInterpreterFromConfig()`, inspired by `Py_InitializeFromConfig()` (takes a `_PyInterpreterConfig` instead of `isolated_subinterpreter`)
3. split up the boolean `isolated_subinterpreter` into the corresponding multiple granular settings
* allow_fork
* allow_subprocess
* allow_threads
4. add `PyInterpreterState.feature_flags` to store those settings
5. add a function for checking if a feature is enabled on an opaque `PyInterpreterState *`
6. drop `PyConfig._isolated_interpreter`
The existing default (see `Py_NewInterpeter()` and `Py_Initialize*()`) allows fork, subprocess, and threads and the optional "isolated" interpreter (see the `_xxsubinterpreters` module) disables all three. None of that changes here; the defaults are preserved.
Note that the given `_PyInterpreterConfig` will not be used outside `_Py_NewInterpreterFromConfig()`, nor preserved. This contrasts with how `PyConfig` is currently preserved, used, and even modified outside `Py_InitializeFromConfig()`. I'd rather just avoid that mess from the start for `_PyInterpreterConfig`. We can preserve it later if we find an actual need.
This change allows us to follow up with a number of improvements (e.g. stop disallowing subprocess and support disallowing exec instead).
(Note that this PR adds "private" symbols. We'll probably make them public, and add docs, in a separate change.)
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.
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
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")
setup.py no longer defines Py_BUILD_CORE_MODULE. Instead every
module defines the macro before #include "Python.h" unless
Py_BUILD_CORE_BUILTIN is already defined.
Py_BUILD_CORE_BUILTIN is defined for every module that is built by
Modules/Setup.
The PR also simplifies Modules/Setup. Makefile and makesetup
already define Py_BUILD_CORE_BUILTIN and include Modules/internal
for us.
Signed-off-by: Christian Heimes <christian@python.org>
Redefining the PyThreadState_GET() macro in pycore_pystate.h is
useless since it doesn't affect files not including it. Either use
_PyThreadState_GET() directly, or don't use pycore_pystate.h internal
C API. For example, the _testcapi extension don't use the internal C
API, but use the public PyThreadState_Get() function instead.
Replace PyThreadState_Get() with _PyThreadState_GET(). The
_PyThreadState_GET() macro is more efficient than PyThreadState_Get()
and PyThreadState_GET() function calls which call fail with a fatal
Python error.
posixmodule.c and _ctypes extension now include <windows.h> before
pycore header files (like pycore_call.h).
_PyTraceback_Add() now uses _PyErr_Fetch()/_PyErr_Restore() instead
of PyErr_Fetch()/PyErr_Restore().
The _decimal and _xxsubinterpreters extensions are now built with the
Py_BUILD_CORE_MODULE macro defined to get access to the internal C
API.
* 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.
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.
* 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.
(Note: PEP 554 is not accepted and the implementation in the code base is a private one for use in the test suite.)
If code running in a subinterpreter raises an uncaught exception then the "run" call in the calling interpreter fails. A RunFailedError is raised there that summarizes the original exception as a string. The actual exception type, __cause__, __context__, state, etc. are all discarded. This turned out to be functionally insufficient in practice. There is a more helpful solution (and PEP 554 has been updated appropriately).
This change adds the exception propagation behavior described in PEP 554 to the _xxsubinterpreters module. With this change a copy of the original exception is set to __cause__ on the RunFailedError. For now we are using "pickle", which preserves the exception's state. We also preserve the original __cause__, __context__, and __traceback__ (since "pickle" does not preserve those).
https://bugs.python.org/issue32604
An isolated subinterpreter cannot spawn threads, spawn a child
process or call os.fork().
* Add private _Py_NewInterpreter(isolated_subinterpreter) function.
* Add isolated=True keyword-only parameter to
_xxsubinterpreters.create().
* Allow again os.fork() in "non-isolated" subinterpreters.
Eric Snow
Serhiy Storchaka
Victor Stinner
Mark Shannon
Radislav Chugunov
T. Wouters
Irit Katriel
neonene
Christian Heimes
Steve Dower
Dong-hee Na