Fix the name of attributes in the common ABI module (cythonGH-4376)

Attribute names used to be fully qualified like "_cython_3_0_0a9.cython_function_or_method" instead of the plain name.

Closes cython#4373

Author: da-woods

Cython/Utility/CommonStructures.c

@@ -8,6 +8,7 @@ static PyTypeObject* __Pyx_FetchCommonTypeFromSpec(PyObject *module, PyType_Spec
 
 /////////////// FetchCommonType ///////////////
 //@requires:ExtensionTypes.c::FixUpExtensionType
+//@requires:StringTools.c::IncludeStringH
 
 static PyObject *__Pyx_FetchSharedCythonABIModule(void) {
     PyObject *abi_module = PyImport_AddModule((char*) __PYX_ABI_MODULE_NAME);
@@ -37,15 +38,19 @@ static int __Pyx_VerifyCachedType(PyObject *cached_type,
 #if !CYTHON_USE_TYPE_SPECS
 static PyTypeObject* __Pyx_FetchCommonType(PyTypeObject* type) {
     PyObject* abi_module;
+    const char* object_name;
     PyTypeObject *cached_type = NULL;
 
     abi_module = __Pyx_FetchSharedCythonABIModule();
     if (!abi_module) return NULL;
-    cached_type = (PyTypeObject*) PyObject_GetAttrString(abi_module, type->tp_name);
+    // get the final part of the object name (after the last dot)
+    object_name = strrchr(type->tp_name, '.');
+    object_name = object_name ? object_name+1 : type->tp_name;
+    cached_type = (PyTypeObject*) PyObject_GetAttrString(abi_module, object_name);
     if (cached_type) {
         if (__Pyx_VerifyCachedType(
               (PyObject *)cached_type,
-              type->tp_name,
+              object_name,
               cached_type->tp_basicsize,
               type->tp_basicsize) < 0) {
             goto bad;
@@ -56,7 +61,7 @@ static PyTypeObject* __Pyx_FetchCommonType(PyTypeObject* type) {
     if (!PyErr_ExceptionMatches(PyExc_AttributeError)) goto bad;
     PyErr_Clear();
     if (PyType_Ready(type) < 0) goto bad;
-    if (PyObject_SetAttrString(abi_module, type->tp_name, (PyObject *)type) < 0)
+    if (PyObject_SetAttrString(abi_module, object_name, (PyObject *)type) < 0)
         goto bad;
     Py_INCREF(type);
     cached_type = type;
@@ -75,11 +80,14 @@ static PyTypeObject* __Pyx_FetchCommonType(PyTypeObject* type) {
 
 static PyTypeObject *__Pyx_FetchCommonTypeFromSpec(PyObject *module, PyType_Spec *spec, PyObject *bases) {
     PyObject *abi_module, *cached_type = NULL;
+    // get the final part of the object name (after the last dot)
+    const char* object_name = strrchr(spec->name, '.');
+    object_name = object_name ? object_name+1 : spec->name;
 
     abi_module = __Pyx_FetchSharedCythonABIModule();
     if (!abi_module) return NULL;
 
-    cached_type = PyObject_GetAttrString(abi_module, spec->name);
+    cached_type = PyObject_GetAttrString(abi_module, object_name);
     if (cached_type) {
         Py_ssize_t basicsize;
 #if CYTHON_COMPILING_IN_LIMITED_API
@@ -95,7 +103,7 @@ static PyTypeObject *__Pyx_FetchCommonTypeFromSpec(PyObject *module, PyType_Spec
 #endif
         if (__Pyx_VerifyCachedType(
               cached_type,
-              spec->name,
+              object_name,
               basicsize,
               spec->basicsize) < 0) {
             goto bad;
@@ -110,7 +118,7 @@ static PyTypeObject *__Pyx_FetchCommonTypeFromSpec(PyObject *module, PyType_Spec
     cached_type = __Pyx_PyType_FromModuleAndSpec(abi_module, spec, bases);
     if (unlikely(!cached_type)) goto bad;
     if (unlikely(__Pyx_fix_up_extension_type_from_spec(spec, (PyTypeObject *) cached_type) < 0)) goto bad;
-    if (PyObject_SetAttrString(abi_module, spec->name, cached_type) < 0) goto bad;
+    if (PyObject_SetAttrString(abi_module, object_name, cached_type) < 0) goto bad;
 
 done:
     Py_DECREF(abi_module);

tests/run/common_utility_types.srctree

@@ -36,3 +36,16 @@ assert type(a.funcA) is type(b.funcB)
 
 assert a.funcA.func_globals is a.__dict__
 assert b.funcB.func_globals is b.__dict__
+
+# Test that it's possible to look up the name of the class
+from sys import modules
+cy_modules = [ mod for n, mod in modules.items() if n.startswith("_cython_") ]
+# In principle it's possible to have "_cython_" internal modules for multiple
+# different versions of Cython. However, since this is run in an end-to-end test
+# with a very short list of imports it should not happen here.
+assert(len(cy_modules)==1)
+mod = cy_modules[0]
+
+assert '.' not in type(a.funcA).__name__
+func_t = getattr(mod, type(a.funcA).__name__)
+assert func_t is type(a.funcA)