Implement CPython 3.14 subinterpreter APIs - #8605

…lementations (GH-156684)

See also RustPython/RustPython#8605

…her implementations (GH-156684) (GH-156688)

See also RustPython/RustPython#8605

(cherry picked from commit 03503dc)

Co-authored-by: sai <[email protected]>

…her implementations (GH-156684) (GH-156687)

See also RustPython/RustPython#8605

(cherry picked from commit 03503dc)

Co-authored-by: sai <[email protected]>

…her implementations (GH-156684) (#156686)

gh-156676: Skip `test_pyinit_function_raises_exception` for other implementations (GH-156684)

See also RustPython/RustPython#8605
(cherry picked from commit 03503dc)

Co-authored-by: sai <[email protected]>

…er implementations (pythonGH-156684)

See also RustPython/RustPython#8605

* Add _interpreters and _interpchannels modules

Apply the patch baseline for the low-level subinterpreter modules:

- crates/vm/src/stdlib/_interpreters.rs: create/destroy/list_all/get_main/
  get_current/is_running/exec/call/run_string/run_func/set___main___attrs/
  is_shareable/whence and the Interpreter*Error exceptions
- crates/vm/src/stdlib/_interpchannels.rs: channel create/destroy/send/recv/
  list_all/list_interpreters/release/close and the Channel*Error exceptions
- crates/vm/src/vm/crossinterp.rs: cross-interpreter data protocol
- crates/vm/src/vm/{interpreter,mod,runtime,vm_new}.rs: interpreter registry
  and lifecycle plumbing the modules need
- Lib/concurrent/interpreters/: high-level PEP 734 package

Assisted-by: Claude:claude-opus-5

* Correct _interpreters and _interpchannels against CPython 3.14

Argument matching:
- Add `function::ArgSpec`, a `PyArg_ParseTupleAndKeywords` equivalent that
  applies the `|`, `$` and `:` markers of a format string to a `kwlist`, and
  route every module function of both modules through it. This enforces
  keyword-only parameters, rejects unexpected keywords, accepts keyword forms
  that were previously positional-only (`whence(id=)`, `get_config(id=)`,
  `set___main___attrs(id=, updates=)`, `capture_exception(exc=)`,
  `_register_end_types(send=, recv=)`), and reproduces the arity messages.
- `O!` slots (`shared`, `updates`, `call`'s `args`/`kwargs`) now reject None,
  and `_PyArg_BadArgument` renders None as "None" rather than "NoneType".
- `new_config` takes at most one positional `str`; `list_all` of
  `_interpchannels` is argument-less.
- Convert arguments in `kwlist` order, so an argument's own error is raised
  ahead of the checks that follow it.

_interpreters:
- Add the `CrossInterpreterBufferView` type and build the received memoryview
  on it, keeping the sending interpreter's exporter out of the destination.
- Build `excinfo.errdisplay` from `traceback.TracebackException`.

Feature flags:
- `os.fork` checks finalization before `allow_fork`, matching `os_fork_impl`.
- `_thread.start_new_thread` and `start_joinable_thread` reject an interpreter
  without `allow_threads`.

Lib/concurrent/interpreters/_crossinterp.py: restore the stripped docstrings
and comments.

Assisted-by: Claude:claude-opus-5

* Correct the stateless checks and error shapes of _interpreters against CPython 3.14

verify_stateless_function follows _PyFunction_VerifyStateless: it rejects
non-dict builtins, a non-empty __defaults__, __kwdefaults__ or __closure__,
and code whose LOAD_GLOBAL names are held by the function's globals or
absent from its builtins.

code_returns_only_none follows _PyCode_ReturnsOnlyNone: generator,
coroutine and async-generator code is rejected up front, the instruction
walk skips inline caches and maps specialized and instrumented opcodes
back, and the LOAD_CONST preceding each RETURN_VALUE is compared against
the index of None in co_consts.

ExcInfo::capture keeps an empty exception message instead of dropping it,
and builds `formatted` as `module.qualname: msg`, leaving out the builtins
and __main__ modules.

_interpreters.call packs the callable through _PyFunction_GetXIData before
pickle and re-raises the stateless-check failure when both fail. A func,
args or kwargs that cannot be rebuilt in the target, and a result without
cross-interpreter data, now raise NotShareableError with the snapshot as
the cause rather than being returned as excinfo.

_interpreters.capture_exception() without an argument returns None.

pickle_loads and _PyFunction_GetXIData attach the underlying failure as
__cause__.

channel_send converts the object to cross-interpreter data after the
channel's `closing` check.

ChannelID rich comparison returns the result of comparing its id with the
other number instead of coercing that result to bool.

PyMemoryView_FromObjectAndFlags raises "memoryview: a bytes-like object is
required, not 'X'" for an object that is not a buffer.

Assisted-by: Claude:claude-opus-5

* Correct cross-interpreter data conversion and channel argument parsing

Bound shareable ints by isize, raising OverflowError("try sending as
bytes") outside that range and keeping it as the NotShareableError cause.

Report an unshareable object by its repr, and attach a failing conversion
as __cause__ of the NotShareableError raised for the object it was called
for, so each level of a nested tuple appears in the chain.

Guard each tuple item conversion with with_recursion("while sharing a
tuple").

Gate the memoryview getdata function on `_interpreters` having been
imported, and route channel_send_buffer through a memoryview so it uses
that function and the resolved fallback.

Create the cross-interpreter exception types from the module_exec of
either module that raises them, instead of only `_interpreters`.

parse_cid raises OverflowError("int too big to convert"); int_arg
reproduces the `i` converter's three overflow messages and is also used
while parsing channel_send arguments.

Add BASETYPE to _queue.Empty, and gate nt.execv/nt.execve on allow_exec.

Assisted-by: Claude:claude-opus-5

* Correct interpreter ID parsing and the channel_send defaults lookup

_PyInterpreterState_ObjectToID accepts any object with __index__, raises
OverflowError("int too big to convert") outside the int64 range, and
reports a negative ID with the repr of the original object.

channelsmod_send reads the channel's default unboundop and fallback only
when one of the two arguments is negative, so an explicit pair is
validated before the channel is looked up.

Assisted-by: Claude:claude-opus-5

* Add the _interpqueues module and concurrent.interpreters._queues

_interpqueues holds a process-wide queue table and exposes create,
destroy, list_all, put, get, bind, release, get_maxsize,
get_queue_defaults, is_full, get_count and _register_heap_types, raising
QueueError and QueueNotFoundError.  QueueEmpty and QueueFull, which
subclass queue.Empty and queue.Full, are registered per interpreter by
concurrent.interpreters._queues.

Cross-interpreter data carries a queue as a refcounted queue ID that
binds when the data is captured and releases when it is dropped, and
is_shareable reports a registered Queue as shareable.

Queue and channel items owned by an interpreter are now cleared from
Interpreter::finalize, after module finalization, rather than from
destroy_owned_interpreter, so values sent by an atexit callback also
become unbound.

is_shareable gates memoryview on the same registration flag as the
getdata lookup.

Assisted-by: Claude:claude-opus-5

* Add the high-level concurrent.interpreters API

Interpreter, ExecutionFailed and the queue aliases, copied verbatim from
CPython 3.14.

Assisted-by: Claude:claude-opus-5

* Destroy leftover subinterpreters when the main interpreter finalizes

Interpreter::finalize now runs finalize_subinterpreters between the atexit
handlers and the finalizing flag: when the main interpreter still owns
subinterpreters it emits the RuntimeWarning "remaining subinterpreters;
close them with Interpreter.close()" and then finalizes each of them.

runtime::owned_interpreter_ids lists the runtime-owned interpreters.

Assisted-by: Claude:claude-opus-5

* Absolutize the script path in run_file

_Py_abspath and _PyPathConfig_ComputeSysPath0 arrive as abs_path and
script_sys_path0. run_file hands the absolutized path to get_importer
and to the runner, so __file__ and co_filename no longer stay relative,
and inserts the symlink-resolved script directory as sys.path[0]
instead of the argument's parent.

test_cmd_line_script.test_script_abspath no longer expects a failure.

Assisted-by: Claude:claude-opus-5

* Name types in error messages the way tp_name does

The object, number, sequence and mapping protocols, the
unsupported-operand helpers, and the type-specific messages fed from
them now read PyType::slot_name() where they read PyType::name(),
so a type declared with a module keeps it.

Message texts corrected along the way:
- PySequence_Size, PyMapping_Size, PySequence_GetItem and
  PySequence_SetItem/DelItem split their merged wording in two, and
  PyObject_SetItem/DelItem say "object".
- PyObject_GenericSetAttr reports a read-only attribute and the
  missing __dict__.
- check_class drops the type name it appended.
- __int__ and __index__ drop the class prefix; __float__ keeps it.
- float(), complex(), round(), next(), str subscripting and list
  subscripting take their own wording.
- str.join and bytes.join number the item they turn down and name what
  they wanted, and report a non-iterable as "can only join an
  iterable".

test_class.testObjectAttributeAccessErrorMessages,
string_tests.test_subscript and the test_descrtut doctest no longer
expect a failure.

Assisted-by: Claude:claude-opus-5

* Gate script_code's source compilation on the compiler feature

crossinterp::script_code called vm.compile unconditionally, which only
exists with the rustpython-compiler feature. Builds without it, such as
example_projects/barebone, now raise a TypeError instead of failing to
compile.

Assisted-by: Claude:claude-opus-5

* Skip test_pyinit_function_raises_exception

The test imports _testsinglephase in its body without a decorator
guarding it, and now that _interpreters exists requires_subinterpreters
no longer skips it.

Assisted-by: Claude:claude-opus-5