Get a first classmethod extraction working

jedi/api/refactoring.py

@@ -8,6 +8,7 @@ from parso import split_lines
 from jedi import debug
 from jedi.api.exceptions import RefactoringError
 from jedi.common.utils import indent_block
+from jedi.parser_utils import function_is_classmethod, function_is_staticmethod
 
 _EXPRESSION_PARTS = (
     'or_test and_test not_test comparison '
@@ -380,8 +381,6 @@ def _is_not_extractable_syntax(node):
 
 
 def extract_function(inference_state, path, module_context, name, pos, until_pos):
-    is_class_method = False
-    is_method = False
     is_expression = True
     nodes = _find_nodes(module_context.tree_node, pos, until_pos)
     return_variables = []
@@ -405,13 +404,14 @@ def extract_function(inference_state, path, module_context, name, pos, until_pos
         output_var_str = ', '.join(return_variables)
         code_block += '\nreturn ' + output_var_str + '\n'
 
-    if not context.is_bound_method():
+    decorator = ''
+    if context.is_bound_method():
+        if function_is_classmethod(context.tree_node):
+            decorator = '@classmethod\n'
+    else:
         code_block += '\n'
 
     function_call = '%s(%s)' % (name, ', '.join(params))
-    decorator = ''
-    if is_class_method:
-        decorator = '@classmethod\n'
     function_code = '%sdef %s:\n%s' % (decorator, function_call, indent_block(code_block))
 
     if is_expression:

test/refactor/extract_function.py

@@ -61,3 +61,19 @@ class X:
     def f(x):
         #? 11 text {'new_name': 'ab'}
         return ab()
+# -------------------------------------------------- in-classmethod-1
+class X:
+    @classmethod
+    def f(x):
+        #? 16 text {'new_name': 'ab'}
+        return 25
+# ++++++++++++++++++++++++++++++++++++++++++++++++++
+class X:
+    @classmethod
+    def ab():
+        return 25
+
+    @classmethod
+    def f(x):
+        #? 16 text {'new_name': 'ab'}
+        return x.ab()