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
youknowone · Aug 30, 2026 · Aug 21, 2026 · Aug 22, 2026 · Aug 22, 2026 · Aug 22, 2026
commit d8a4366122de7789ff4f018be653d68a30fdac9c
diff --git a/.cspell.dict/cpython.txt b/.cspell.dict/cpython.txt
@@ -35,6 +35,8 @@ ceval
 cfield
 cfws
 CFWS
+chans
+cidx
 CLASSDEREF
 classdict
 cmpop
@@ -170,6 +172,7 @@ nseen
 NSIGNALS
 numer
 nvars
+obmalloc
 opname
 opnames
 orelse
@@ -206,6 +209,7 @@ PYTHONTRACEMALLOC
 PYTHONUTF8
 pythonw
 PYTHREAD_NAME
+recvd
 releasebuffer
 repr
 resinfo
@@ -256,6 +260,7 @@ Typeparam
 typeparams
 typeslots
 unaryop
+unboundop
 uncollectable
 Unhandle
 unparse

diff --git a/Lib/concurrent/interpreters/__init__.py b/Lib/concurrent/interpreters/__init__.py
@@ -0,0 +1,6 @@
+"""Subinterpreters High Level Module."""
+
+# The high-level `concurrent.interpreters` API is built on `_interpreters`.
+# This package is introduced incrementally; `_crossinterp` is shared with
+# the low-level `_interpchannels` tests.
+
diff --git a/Lib/concurrent/interpreters/_crossinterp.py b/Lib/concurrent/interpreters/_crossinterp.py
@@ -0,0 +1,96 @@
+"""Common code between queues and channels."""
+
+
+class ItemInterpreterDestroyed(Exception):
+    """Raised when trying to get an item whose interpreter was destroyed."""
+
+
+class classonly:
+    """A non-data descriptor that makes a value only visible on the class."""
+
+    def __init__(self, value):
+        self.value = value
+        self.getter = classmethod(value).__get__
+        self.name = None
+
+    def __set_name__(self, cls, name):
+        if self.name is not None:
+            raise TypeError('already used')
+        self.name = name
+
+    def __get__(self, obj, cls):
+        if obj is not None:
+            raise AttributeError(self.name)
+        return self.getter(None, cls)
+
+
+class UnboundItem:
+    """Represents a cross-interpreter item no longer bound to an interpreter."""
+
+    __slots__ = ()
+
+    @classonly
+    def singleton(cls, kind, module, name='UNBOUND'):
+        doc = cls.__doc__
+        if doc:
+            doc = doc.replace(
+                'cross-interpreter container', kind,
+            ).replace(
+                'cross-interpreter', kind,
+            )
+        subclass = type(
+            f'Unbound{kind.capitalize()}Item',
+            (cls,),
+            {
+                "_MODULE": module,
+                "_NAME": name,
+                "__doc__": doc,
+            },
+        )
+        return object.__new__(subclass)
+
+    _MODULE = __name__
+    _NAME = 'UNBOUND'
+
+    def __new__(cls):
+        raise Exception(f'use {cls._MODULE}.{cls._NAME}')
+
+    def __repr__(self):
+        return f'{self._MODULE}.{self._NAME}'
+
+
+UNBOUND = object.__new__(UnboundItem)
+UNBOUND_ERROR = object()
+UNBOUND_REMOVE = object()
+
+_UNBOUND_CONSTANT_TO_FLAG = {
+    UNBOUND_REMOVE: 1,
+    UNBOUND_ERROR: 2,
+    UNBOUND: 3,
+}
+_UNBOUND_FLAG_TO_CONSTANT = {v: k
+                             for k, v in _UNBOUND_CONSTANT_TO_FLAG.items()}
+
+
+def serialize_unbound(unbound):
+    op = unbound
+    try:
+        flag = _UNBOUND_CONSTANT_TO_FLAG[op]
+    except KeyError:
+        raise NotImplementedError(f'unsupported unbound replacement op {op!r}')
+    return flag,
+
+
+def resolve_unbound(flag, exctype_destroyed):
+    try:
+        op = _UNBOUND_FLAG_TO_CONSTANT[flag]
+    except KeyError:
+        raise NotImplementedError(f'unsupported unbound replacement op {flag!r}')
+    if op is UNBOUND_REMOVE:
+        raise NotImplementedError
+    elif op is UNBOUND_ERROR:
+        raise exctype_destroyed("item's original interpreter destroyed")
+    elif op is UNBOUND:
+        return UNBOUND
+    else:
+        raise NotImplementedError(repr(op))
diff --git a/crates/vm/src/builtins/memory.rs b/crates/vm/src/builtins/memory.rs
@@ -118,6 +118,13 @@ impl PyMemoryView {
         Self::from_object_with_flags(obj, BufferFlags::FULL_RO, vm)
     }
 
+    /// One share of the underlying buffer export. Used for cross-interpreter
+    /// `send_buffer` so the destination memoryview sees the same memory.
+    #[must_use]
+    pub fn clone_buffer(&self) -> PyBuffer {
+        self.buffer.clone()
+    }
+
     // PyMemoryView_FromObjectAndFlags
     pub fn from_object_with_flags(
         obj: &PyObject,

diff --git a/crates/vm/src/lib.rs b/crates/vm/src/lib.rs
@@ -111,8 +111,9 @@ pub use self::object::{
 };
 pub use self::vm::runtime;
 pub use self::vm::{
-    Context, Interpreter, InterpreterBuilder, InterpreterInfo, InterpreterWhence,
-    MAIN_INTERPRETER_ID, Settings, VirtualMachine,
+    Context, InterpFeatureFlags, Interpreter, InterpreterBuilder, InterpreterConfig,
+    InterpreterGil, InterpreterInfo, InterpreterWhence, MAIN_INTERPRETER_ID, Settings,
+    VirtualMachine,
 };
 
 pub use rustpython_common as common;