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gh-99113: Add a check for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED (gh-10…
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Py_MOD_PER_INTERPRETER_GIL_SUPPORTED is a new supported value for Py_mod_multiple_interpreters, added in gh-104205.
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ericsnowcurrently authored May 6, 2023
1 parent 3b14b51 commit fff193b
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Showing 5 changed files with 99 additions and 2 deletions.
20 changes: 20 additions & 0 deletions Lib/test/test_import/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -1861,6 +1861,26 @@ def test_multi_init_extension_non_isolated_compat(self):
with self.subTest(f'{modname}: not strict'):
self.check_compatible_here(modname, filename, strict=False)

@unittest.skipIf(_testmultiphase is None, "test requires _testmultiphase module")
def test_multi_init_extension_per_interpreter_gil_compat(self):
modname = '_test_shared_gil_only'
filename = _testmultiphase.__file__
loader = ExtensionFileLoader(modname, filename)
spec = importlib.util.spec_from_loader(modname, loader)
module = importlib.util.module_from_spec(spec)
loader.exec_module(module)
sys.modules[modname] = module

require_extension(module)
with self.subTest(f'{modname}: isolated, strict'):
self.check_incompatible_here(modname, filename, isolated=True)
with self.subTest(f'{modname}: not isolated, strict'):
self.check_compatible_here(modname, filename,
strict=True, isolated=False)
with self.subTest(f'{modname}: not isolated, not strict'):
self.check_compatible_here(modname, filename,
strict=False, isolated=False)

def test_python_compat(self):
module = 'threading'
require_pure_python(module)
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2 changes: 2 additions & 0 deletions Lib/test/test_importlib/extension/test_loader.py
Original file line number Diff line number Diff line change
Expand Up @@ -348,6 +348,8 @@ def test_bad_modules(self):
'exec_err',
'exec_raise',
'exec_unreported_exception',
'multiple_create_slots',
'multiple_multiple_interpreters_slots',
]:
with self.subTest(name_base):
name = self.name + '_' + name_base
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
Multi-phase init extension modules may now indicate that they support
running in subinterpreters that have their own GIL. This is done by using
``Py_MOD_PER_INTERPRETER_GIL_SUPPORTED`` as the value for the
``Py_mod_multiple_interpreters`` module def slot. Otherwise the module, by
default, cannot be imported in such subinterpreters. (This does not affect
the main interpreter or subinterpreters that do not have their own GIL.) In
addition to the isolation that multi-phase init already normally requires,
support for per-interpreter GIL involves one additional constraint:
thread-safety. If the module has external (linked) dependencies and those
libraries have any state that isn't thread-safe then the module must do the
additional work to add thread-safety. This should be an uncommon case.
60 changes: 59 additions & 1 deletion Modules/_testmultiphase.c
Original file line number Diff line number Diff line change
Expand Up @@ -681,6 +681,27 @@ PyInit__testmultiphase_export_unreported_exception(void)
return PyModuleDef_Init(&main_def);
}

static PyObject*
createfunc_noop(PyObject *spec, PyModuleDef *def)
{
return PyModule_New("spam");
}

static PyModuleDef_Slot slots_multiple_create_slots[] = {
{Py_mod_create, createfunc_noop},
{Py_mod_create, createfunc_noop},
{0, NULL},
};

static PyModuleDef def_multiple_create_slots = TEST_MODULE_DEF(
"_testmultiphase_multiple_create_slots", slots_multiple_create_slots, NULL);

PyMODINIT_FUNC
PyInit__testmultiphase_multiple_create_slots(void)
{
return PyModuleDef_Init(&def_multiple_create_slots);
}

static PyObject*
createfunc_null(PyObject *spec, PyModuleDef *def)
{
Expand Down Expand Up @@ -892,7 +913,24 @@ PyInit__test_module_state_shared(void)
}


/* multiple interpreters supports */
/* multiple interpreters support */

static PyModuleDef_Slot slots_multiple_multiple_interpreters_slots[] = {
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{0, NULL},
};

static PyModuleDef def_multiple_multiple_interpreters_slots = TEST_MODULE_DEF(
"_testmultiphase_multiple_multiple_interpreters_slots",
slots_multiple_multiple_interpreters_slots,
NULL);

PyMODINIT_FUNC
PyInit__testmultiphase_multiple_multiple_interpreters_slots(void)
{
return PyModuleDef_Init(&def_multiple_multiple_interpreters_slots);
}

static PyModuleDef_Slot non_isolated_slots[] = {
{Py_mod_exec, execfunc},
Expand All @@ -909,3 +947,23 @@ PyInit__test_non_isolated(void)
{
return PyModuleDef_Init(&non_isolated_def);
}


static PyModuleDef_Slot shared_gil_only_slots[] = {
{Py_mod_exec, execfunc},
/* Note that Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED is the default.
We put it here explicitly to draw attention to the contrast
with Py_MOD_PER_INTERPRETER_GIL_SUPPORTED. */
{Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED},
{0, NULL},
};

static PyModuleDef shared_gil_only_def = TEST_MODULE_DEF("_test_shared_gil_only",
shared_gil_only_slots,
testexport_methods);

PyMODINIT_FUNC
PyInit__test_shared_gil_only(void)
{
return PyModuleDef_Init(&shared_gil_only_def);
}
8 changes: 7 additions & 1 deletion Objects/moduleobject.c
Original file line number Diff line number Diff line change
Expand Up @@ -323,7 +323,13 @@ PyModule_FromDefAndSpec2(PyModuleDef* def, PyObject *spec, int module_api_versio
goto error;
}
}
// XXX Do a similar check once we have PyInterpreterState.ceval.own_gil.
else if (multiple_interpreters != Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
&& interp->ceval.own_gil
&& !_Py_IsMainInterpreter(interp)
&& _PyImport_CheckSubinterpIncompatibleExtensionAllowed(name) < 0)
{
goto error;
}

if (create) {
m = create(spec, def);
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