Merge pull request github#17809 from github/tausbn/python-fix-kwargs-in-class-bases

Python: Fix bug in handling of `**kwargs` in class bases

Author: tausbn

python/extractor/tests/parser/class.py

@@ -1,2 +1,2 @@
-class Foo(int, object, metaclass=type):
+class Foo(int, object, metaclass=type, **kwargs):
     x = 5

python/extractor/tsg-python/python.tsg

@@ -1277,16 +1277,18 @@
     attr (@class.inner_scope -> @stmt.node) body = (named-child-index @stmt)
 }
 
-; Class.bases - using `(_ !name)` as a proxy for all non-keyword arguments.
+; Class.bases - using `(_  !value !name)` as a proxy for all non-keyword arguments.
+; In particular, `keyword_argument` nodes have a `name` field, and `dictionary_splat`
+; nodes have a `value` field.
 (class_definition
-    superclasses: (argument_list element: (_ !name) @arg)
+    superclasses: (argument_list element: (_ !value !name) @arg)
 ) @class
 {
     edge @class.class_expr -> @arg.node
     attr (@class.class_expr -> @arg.node) bases = (named-child-index @arg)
 }
 
-; Class.keywords
+; Class.keywords of the form `foo=bar`
 (class_definition
     superclasses: (argument_list element: (keyword_argument) @arg)
 ) @class
@@ -1295,6 +1297,15 @@
     attr (@class.class_expr -> @arg.node) keywords = (named-child-index @arg)
 }
 
+; Class.keywords of the form `**kwargs`
+(class_definition
+    superclasses: (argument_list element: (dictionary_splat) @arg)
+) @class
+{
+    edge @class.class_expr -> @arg.node
+    attr (@class.class_expr -> @arg.node) keywords = (named-child-index @arg)
+}
+
 ;;;;;; End of Class
 
 ;;;;;; Assign statements