Fix E721 type comparison pattern handling

autopep8.py

@@ -1300,6 +1300,7 @@ def fix_e721(self, result):
             # NOTE: match objects
             #  * type(a) == type(b)  -> (None, None, 'a', '==')
             #  * str == type(b)      -> ('==', 'b', None, None)
+            #  * type(b) == str      -> (None, None, 'b', '==')
             #  * type("") != type(b) -> (None, None, '""', '!=')
             start = match.start()
             end = match.end()
@@ -1320,6 +1321,10 @@ def fix_e721(self, result):
                 isinstance_stmt = " not isinstance"
 
             _type_comp = f"{_target_obj}, {target[:start]}"
+            indent_match = re.match(r'^\s+', target)
+            indent = ""
+            if indent_match:
+                indent = indent_match.group()
 
             _prefix_tmp = target[:start].split()
             if len(_prefix_tmp) >= 1:
@@ -1332,15 +1337,28 @@ def fix_e721(self, result):
 
             _suffix_tmp = target[end:]
             _suffix_type_match = TYPE_REGEX.search(_suffix_tmp)
-            if len(_suffix_tmp.split()) >= 1 and _suffix_type_match:
-                if _suffix_type_match:
+            if _suffix_type_match:
+                if len(_suffix_tmp.split()) >= 1:
                     type_match_end = _suffix_type_match.end()
                     _suffix = _suffix_tmp[type_match_end:]
-            if _suffix_type_match:
                 cmp_b = _suffix_type_match.groups()[0]
                 _type_comp = f"{_target_obj}, {cmp_b}"
-
-            fix_line = f"{_prefix}{isinstance_stmt}({_type_comp}){_suffix}"
+            else:
+                _else_suffix_match = re.match(
+                    r"^\s*([^\s:]+)(.*)$",
+                    _suffix_tmp,
+                )
+                if _else_suffix_match:
+                    _else_suffix = _else_suffix_match.group(1)
+                    _else_suffix_other = _else_suffix_match.group(2)
+                    _type_comp = f"{_target_obj}, {_else_suffix}"
+                    _else_suffix_end = _suffix_tmp[_else_suffix_match.end():]
+                    _suffix = f"{_else_suffix_other}{_else_suffix_end}"
+                # `else` route is not care
+
+            fix_line = (
+                f"{indent}{_prefix}{isinstance_stmt}({_type_comp}){_suffix}"
+            )
             self.source[line_index] = fix_line
 
     def fix_e722(self, result):

test/test_autopep8.py

@@ -4419,6 +4419,18 @@ def test_e721_in_conditional_pat2(self):
         with autopep8_context(line, options=['--aggressive']) as result:
             self.assertEqual(fixed, result)
 
+    def test_e721_in_conditional_pat3(self):
+        line = "if type(res) == str:\n    pass\n"
+        fixed = "if isinstance(res, str):\n    pass\n"
+        with autopep8_context(line, options=['--aggressive']) as result:
+            self.assertEqual(fixed, result)
+
+    def test_e721_in_conditional_with_indent(self):
+        line = "if True:\n    if str == type(''):\n        pass\n"
+        fixed = "if True:\n    if isinstance('', str):\n        pass\n"
+        with autopep8_context(line, options=['--aggressive']) as result:
+            self.assertEqual(fixed, result)
+
     def test_e721_in_not_conditional(self):
         line = "if type(res) != type(''):\n    pass\n"
         fixed = "if not isinstance(res, type('')):\n    pass\n"