bpo-41194: The _ast module cannot be loaded more than once (GH-21290)

bpo-41194: The _ast module cannot be loaded more than once (GH-21290) · python/cpython@91e1bc1

@@ -691,7 +691,7 @@ def visitModule(self, mod):

691691 Py_ssize_t i, numfields = 0;692692 int res = -1;693693 PyObject *key, *value, *fields;694- astmodulestate *state = astmodulestate_global;694+ astmodulestate *state = get_global_ast_state();695695 if (_PyObject_LookupAttr((PyObject*)Py_TYPE(self), state->_fields, &fields) < 0) {696696 goto cleanup;697697 }

@@ -760,7 +760,7 @@ def visitModule(self, mod):

760760static PyObject *761761ast_type_reduce(PyObject *self, PyObject *unused)762762{763- astmodulestate *state = astmodulestate_global;763+ astmodulestate *state = get_global_ast_state();764764 PyObject *dict;765765 if (_PyObject_LookupAttr(self, state->__dict__, &dict) < 0) {766766 return NULL;

@@ -971,19 +971,7 @@ def visitModule(self, mod):

971971972972self.emit("static int init_types(void)",0)973973self.emit("{", 0)974-self.emit("PyObject *module = PyState_FindModule(&_astmodule);", 1)975-self.emit("if (module == NULL) {", 1)976-self.emit("module = PyModule_Create(&_astmodule);", 2)977-self.emit("if (!module) {", 2)978-self.emit("return 0;", 3)979-self.emit("}", 2)980-self.emit("if (PyState_AddModule(module, &_astmodule) < 0) {", 2)981-self.emit("return 0;", 3)982-self.emit("}", 2)983-self.emit("}", 1)984-self.emit("", 0)985-986-self.emit("astmodulestate *state = get_ast_state(module);", 1)974+self.emit("astmodulestate *state = get_global_ast_state();", 1)987975self.emit("if (state->initialized) return 1;", 1)988976self.emit("if (init_identifiers(state) < 0) return 0;", 1)989977self.emit("state->AST_type = PyType_FromSpec(&AST_type_spec);", 1)

@@ -1061,13 +1049,16 @@ def visitModule(self, mod):

10611049self.emit("PyMODINIT_FUNC", 0)10621050self.emit("PyInit__ast(void)", 0)10631051self.emit("{", 0)1064-self.emit("PyObject *m;", 1)1065-self.emit("if (!init_types()) return NULL;", 1)1066-self.emit('m = PyState_FindModule(&_astmodule);', 1)1067-self.emit("if (!m) return NULL;", 1)1052+self.emit("PyObject *m = PyModule_Create(&_astmodule);", 1)1053+self.emit("if (!m) {", 1)1054+self.emit("return NULL;", 2)1055+self.emit("}", 1)10681056self.emit('astmodulestate *state = get_ast_state(m);', 1)10691057self.emit('', 1)107010581059+self.emit("if (!init_types()) {", 1)1060+self.emit("goto error;", 2)1061+self.emit("}", 1)10711062self.emit('if (PyModule_AddObject(m, "AST", state->AST_type) < 0) {', 1)10721063self.emit('goto error;', 2)10731064self.emit('}', 1)

@@ -1084,6 +1075,7 @@ def visitModule(self, mod):

10841075for dfn in mod.dfns:10851076self.visit(dfn)10861077self.emit("return m;", 1)1078+self.emit("", 0)10871079self.emit("error:", 0)10881080self.emit("Py_DECREF(m);", 1)10891081self.emit("return NULL;", 1)

@@ -1263,9 +1255,11 @@ class PartingShots(StaticVisitor):

12631255CODE = """12641256PyObject* PyAST_mod2obj(mod_ty t)12651257{1266- if (!init_types())1258+ if (!init_types()) {12671259 return NULL;1268- astmodulestate *state = astmodulestate_global;1260+ }1261+1262+ astmodulestate *state = get_global_ast_state();12691263 return ast2obj_mod(state, t);12701264}12711265

@@ -1279,16 +1273,17 @@ class PartingShots(StaticVisitor):

12791273 return NULL;12801274 }128112751282- astmodulestate *state = astmodulestate_global;1276+ astmodulestate *state = get_global_ast_state();12831277 PyObject *req_type[3];12841278 req_type[0] = state->Module_type;12851279 req_type[1] = state->Expression_type;12861280 req_type[2] = state->Interactive_type;1287128112881282 assert(0 <= mode && mode <= 2);128912831290- if (!init_types())1284+ if (!init_types()) {12911285 return NULL;1286+ }1292128712931288 isinstance = PyObject_IsInstance(ast, req_type[mode]);12941289 if (isinstance == -1)

@@ -1308,9 +1303,11 @@ class PartingShots(StaticVisitor):

1308130313091304int PyAST_Check(PyObject* obj)13101305{1311- if (!init_types())1306+ if (!init_types()) {13121307 return -1;1313- astmodulestate *state = astmodulestate_global;1308+ }1309+1310+ astmodulestate *state = get_global_ast_state();13141311 return PyObject_IsInstance(obj, state->AST_type);13151312}13161313"""

@@ -1361,13 +1358,12 @@ def generate_module_def(f, mod):

13611358f.write(' PyObject *' + s + ';\n')13621359f.write('} astmodulestate;\n\n')13631360f.write("""1361+static astmodulestate global_ast_state;1362+13641363static astmodulestate *1365-get_ast_state(PyObject *module)1364+get_ast_state(PyObject *Py_UNUSED(module))13661365{1367- assert(module != NULL);1368- void *state = PyModule_GetState(module);1369- assert(state != NULL);1370- return (astmodulestate *)state;1366+ return &global_ast_state;13711367}1372136813731369static int astmodule_clear(PyObject *module)

@@ -1396,17 +1392,14 @@ def generate_module_def(f, mod):

1396139213971393static struct PyModuleDef _astmodule = {13981394 PyModuleDef_HEAD_INIT,1399- "_ast",1400- NULL,1401- sizeof(astmodulestate),1402- NULL,1403- NULL,1404- astmodule_traverse,1405- astmodule_clear,1406- astmodule_free,1395+ .m_name = "_ast",1396+ .m_size = -1,1397+ .m_traverse = astmodule_traverse,1398+ .m_clear = astmodule_clear,1399+ .m_free = astmodule_free,14071400};140814011409-#define astmodulestate_global get_ast_state(PyState_FindModule(&_astmodule))1402+#define get_global_ast_state() (&global_ast_state)1410140314111404""")14121405f.write('static int init_identifiers(astmodulestate *state)\n')