Manually type-check the instance variable during method invocations on Python 3HEADpy3k

1 files changed, 59 insertions, 0 deletions

diff --git a/gi/pygi-info.c b/gi/pygi-info.c
index 6f89e51..454b06c 100644
--- a/gi/pygi-info.c
+++ b/gi/pygi-info.c
@@ -710,6 +710,65 @@ _wrap_g_function_info_invoke (PyGIBaseInfo *self,
         g_assert(py_args_pos == n_py_args);
     }
 
+#if PY_MAJOR_VERSION >= 3
+    if (is_method) {
+        /*
+          In Python 2, type-checking of the instance is done for us by
+          Objects/classobject.c:instancemethod_call, which will raise
+          a TypeError of the form 
+              "unbound method %s%s must be called with "
+              "%s instance as first argument "
+              "(got %s%s instead)",
+
+          In Python 3, it appears that this checking isn't done for us,
+          so we do it here:
+        */
+        GIBaseInfo *container_info;
+        PyObject *py_expected_type;
+        PyObject *py_arg;
+        int is_instance;
+
+        container_info = g_base_info_get_container(self->info);            
+        py_expected_type = _pygi_type_import_by_gi_info (container_info);
+        
+        if (py_expected_type == NULL) {
+            goto out;
+        }
+        
+        py_arg = PyTuple_GetItem(py_args, 0);
+        if (py_arg == NULL) {
+            Py_DECREF(py_expected_type);
+            goto out;
+        }
+        
+        is_instance = PyObject_IsInstance(py_arg, py_expected_type);
+        if (is_instance == -1) {
+            Py_DECREF(py_expected_type);
+            goto out;
+        }
+        
+        if (is_instance == 0) {
+            gchar *type_name_expected;
+    
+            type_name_expected = _pygi_g_base_info_get_fullname(container_info);
+        
+            PyErr_Format(PyExc_TypeError,
+                         "method must be called with "
+                         "%s instance as first argument "
+                         "(got %s instead)",
+                         type_name_expected,
+                         py_arg->ob_type->tp_name
+                         );
+
+            g_free(type_name_expected);
+
+            Py_DECREF(py_expected_type);
+            goto out;
+        }
+        Py_DECREF(py_expected_type);
+    }
+#endif
+
     args = g_newa(GArgument *, n_args);
     in_args = g_newa(GArgument, n_in_args);
     out_args = g_newa(GArgument, n_out_args);