fix B024 & B027 on python < 3.8

Author: jakkdl

README.rst

@@ -296,23 +296,21 @@ MIT
 
 Change Log
 ----------
+Future
+~~~~~~~~~
+
+* Add B027: Empty method in abstract base class with no abstract decorator
 
-<<<<<<< HEAD
 22.9.23
 ~~~~~~~~~~
 
-* add B026: find argument unpacking after keyword argument (#287)
+* Add B026: find argument unpacking after keyword argument (#287)
 * Move to setup.cfg like flake8 (#288)
 
 22.9.11
 ~~~~~~~~~~
 
-* add B025: find duplicate except clauses (#284)
-=======
-Future
-~~~~~~~~~
-* Add B025: Empty method in abstract base class with no abstract decorator.
->>>>>>> 0937a2d (Adding B025: empty method in abstract base class with no abstract decorator)
+* Add B025: find duplicate except clauses (#284)
 
 22.8.23
 ~~~~~~~~~~

bugbear.py

@@ -635,17 +635,17 @@ def is_abstract_decorator(expr):
             )
 
         def empty_body(body) -> bool:
+            def is_str_or_ellipsis(node):
+                # ast.Ellipsis and ast.Str used in python<3.8
+                return isinstance(node, (ast.Ellipsis, ast.Str)) or (
+                    isinstance(node, ast.Constant)
+                    and (node.value is Ellipsis or isinstance(node.value, str))
+                )
+
             # Function body consist solely of `pass`, `...`, and/or (doc)string literals
             return all(
                 isinstance(stmt, ast.Pass)
-                or (
-                    isinstance(stmt, ast.Expr)
-                    and isinstance(stmt.value, ast.Constant)
-                    and (
-                        stmt.value.value is Ellipsis
-                        or isinstance(stmt.value.value, str)
-                    )
-                )
+                or (isinstance(stmt, ast.Expr) and is_str_or_ellipsis(stmt.value))
                 for stmt in body
             )
 

tests/test_bugbear.py

@@ -407,7 +407,7 @@ def test_b027(self):
             B027(16, 4, vars=("empty_2",)),
             B027(19, 4, vars=("empty_3",)),
             B027(23, 4, vars=("empty_4",)),
-            B027(31, 4, vars=("empty_5",)),
+            B027(31 if sys.version_info >= (3, 8) else 30, 4, vars=("empty_5",)),
         )
         self.assertEqual(errors, expected)