gh-157047: Support sharing of complex types in subinterpreters

Doc/library/concurrent.interpreters.rst

@@ -189,6 +189,7 @@ objects are either directly shared or copied efficiently.  For example:
 * :class:`str`
 * :class:`int`
 * :class:`float`
+* :class:`complex`
 * :class:`tuple` (of similarly supported objects)
 
 There are a small number of Python types that actually share mutable

Lib/test/test__interpreters.py

@@ -104,6 +104,7 @@ def test_default_shareables(self):
                 True,
                 False,
                 100.0,
+                1+2j,
                 (1, ('spam', 'eggs')),
                 ]
         for obj in shareables:
@@ -603,6 +604,7 @@ def test_shareable_types(self):
             'spam',
             b'spam',
             42,
+            1+2j,
         ]
         for obj in objects:
             with self.subTest(obj):

Lib/test/test_crossinterp.py

@@ -124,6 +124,10 @@ def ignore_byteswarning():
     -1.0,
     0.12345678,
     -0.12345678,
+    # complex
+    0j,
+    1+2j,
+    -1-2j,
 ]
 TUPLE_EXCEPTION = (0, 1.0, EXCEPTION)
 TUPLE_OBJECT = (0, 1.0, OBJECT)
@@ -1326,6 +1330,9 @@ def test_float(self):
             -0.12345678,
         ])
 
+    def test_complex(self):
+        self.assert_roundtrip_equal([0j, 1+2j, -1-2j, 1.5+2.5j])
+
     def test_tuple(self):
         self.assert_roundtrip_equal([
             (),

Lib/test/test_interpreters/test_api.py

@@ -1306,6 +1306,7 @@ def test_stateless_func_returns_arg(self):
         for arg in [
             None,
             10,
+            1+2j,
             'spam!',
             b'spam!',
             (1, 2, 'spam!'),
@@ -1903,6 +1904,7 @@ def test_default_shareables(self):
                 True,
                 False,
                 100.0,
+                1+2j,
                 (),
                 (1, ('spam', 'eggs'), True),
                 ]

Misc/NEWS.d/next/Core_and_Builtins/2026-09-06-22-43-15.gh-issue-157047.ecyJp1.rst

@@ -0,0 +1 @@
+Support sharing of :class:`complex` types in subinterpreters.

Python/crossinterp_data_lookup.h

@@ -555,6 +555,30 @@ _float_shared(PyThreadState *tstate, PyObject *obj, _PyXIData_t *xidata)
     return 0;
 }
 
+// complex
+
+static PyObject *
+_new_complex_object(_PyXIData_t *xidata)
+{
+    Py_complex * value_ptr = xidata->data;
+    return PyComplex_FromCComplex(*value_ptr);
+}
+
+static int
+_complex_shared(PyThreadState *tstate, PyObject *obj, _PyXIData_t *xidata)
+{
+    if (_PyXIData_InitWithSize(
+            xidata, tstate->interp, sizeof(Py_complex), NULL,
+            _new_complex_object
+            ) < 0)
+    {
+        return -1;
+    }
+    Py_complex *shared = (Py_complex *)xidata->data;
+    *shared = PyComplex_AsCComplex(obj);
+    return 0;
+}
+
 // None
 
 static PyObject *
@@ -825,6 +849,11 @@ _register_builtins_for_crossinterpreter_data(dlregistry_t *xidregistry)
         Py_FatalError("could not register float for cross-interpreter sharing");
     }
 
+    // complex
+    if (REGISTER(&PyComplex_Type, _complex_shared) != 0) {
+        Py_FatalError("could not register complex for cross-interpreter sharing");
+    }
+
     // tuple
     if (REGISTER_FALLBACK(&PyTuple_Type, _tuple_shared) != 0) {
         Py_FatalError("could not register tuple for cross-interpreter sharing");