Proxy through query/update of annotations in C version of wrapper.

src/_wrappers.c

@@ -301,6 +301,32 @@ static int WraptWrapperBase_set_doc(WraptWrapperBaseObject *self,
 
 /* ------------------------------------------------------------------------- */
 
+static PyObject *WraptWrapperBase_get_annotations(
+        WraptWrapperBaseObject *self)
+{
+    if (!self->wrapped) {
+      PyErr_SetString(PyExc_ValueError, "wrapper has not been initialised");
+      return NULL;
+    }
+
+    return PyObject_GetAttrString(self->wrapped, "__annotations__");
+}
+
+/* ------------------------------------------------------------------------- */
+
+static int WraptWrapperBase_set_annotations(WraptWrapperBaseObject *self,
+        PyObject *value)
+{
+    if (!self->wrapped) {
+      PyErr_SetString(PyExc_ValueError, "wrapper has not been initialised");
+      return -1;
+    }
+
+    return PyObject_SetAttrString(self->wrapped, "__annotations__", value);
+}
+
+/* ------------------------------------------------------------------------- */
+
 static PyObject *WraptWrapperBase_getattro(
         WraptWrapperBaseObject *self, PyObject *name)
 {
@@ -398,6 +424,8 @@ static PyGetSetDef WraptWrapperBase_getset[] = {
                             (setter)WraptWrapperBase_set_module, 0 },
     { "__doc__",            (getter)WraptWrapperBase_get_doc,
                             (setter)WraptWrapperBase_set_doc, 0 },
+    { "__annotations__",    (getter)WraptWrapperBase_get_annotations,
+                            (setter)WraptWrapperBase_set_annotations, 0 },
     { NULL },
 };
 
@@ -640,6 +668,8 @@ static PyGetSetDef WraptFunctionWrapper_getset[] = {
                             (setter)WraptWrapperBase_set_module, 0 },
     { "__doc__",            (getter)WraptWrapperBase_get_doc,
                             (setter)WraptWrapperBase_set_doc, 0 },
+    { "__annotations__",    (getter)WraptWrapperBase_get_annotations,
+                            (setter)WraptWrapperBase_set_annotations, 0 },
     { NULL },
 };
 
@@ -850,6 +880,8 @@ static PyGetSetDef WraptBoundFunctionWrapper_getset[] = {
                             (setter)WraptWrapperBase_set_module, 0 },
     { "__doc__",            (getter)WraptWrapperBase_get_doc,
                             (setter)WraptWrapperBase_set_doc, 0 },
+    { "__annotations__",    (getter)WraptWrapperBase_get_annotations,
+                            (setter)WraptWrapperBase_set_annotations, 0 },
     { NULL },
 };
 
@@ -1112,6 +1144,8 @@ static PyGetSetDef WraptBoundMethodWrapper_getset[] = {
                             (setter)WraptWrapperBase_set_module, 0 },
     { "__doc__",            (getter)WraptWrapperBase_get_doc,
                             (setter)WraptWrapperBase_set_doc, 0 },
+    { "__annotations__",    (getter)WraptWrapperBase_get_annotations,
+                            (setter)WraptWrapperBase_set_annotations, 0 },
     { NULL },
 };
 

tests/test_update_attributes.py

@@ -129,5 +129,48 @@ class TestUpdateAttributes(unittest.TestCase):
         self.assertEqual(function.__doc__, 'override_doc')
         self.assertEqual(instance.__doc__, 'override_doc')
 
+    def test_update_annotations(self):
+        @passthru_decorator
+        def function():
+            pass
+
+        if six.PY3:
+            self.assertEqual(function.__annotations__, {})
+
+        else:
+            def run(*args):
+                function.__annotations__
+
+            self.assertRaises(AttributeError, run, ())
+
+        override_annotations = { 'override_annotations': '' }
+        function.__annotations__ = override_annotations
+
+        self.assertEqual(function.__annotations__, override_annotations)
+
+    def test_update_annotations_modified_on_original(self):
+        def function():
+            pass
+
+        def wrapper(wrapped, instance, args, kwargs):
+            return wrapped(*args, **kwargs)
+
+        instance = wrapt.FunctionWrapper(function, wrapper)
+
+        if six.PY3:
+            self.assertEqual(instance.__annotations__, {})
+
+        else:
+            def run(*args):
+                instance.__annotations__
+
+            self.assertRaises(AttributeError, run, ())
+
+        override_annotations = { 'override_annotations': '' }
+        instance.__annotations__ = override_annotations
+
+        self.assertEqual(function.__annotations__, override_annotations)
+        self.assertEqual(instance.__annotations__, override_annotations)
+
 if __name__ == '__main__':
     unittest.main()