Merge pull request #856 from asottile/versioned-branches-module-level

dead versioned if statements can be deleted at module scope

pyupgrade/_plugins/versioned_branches.py

@@ -65,6 +65,11 @@ def _fix_py3_block_else(i: int, tokens: list[Token]) -> None:
         if_block.replace_condition(tokens, [Token('NAME', 'else')])
 
 
+def _fix_remove_block(i: int, tokens: list[Token]) -> None:
+    block = Block.find(tokens, i)
+    del tokens[block.start:block.end]
+
+
 def _eq(test: ast.Compare, n: int) -> bool:
     return (
         isinstance(test.ops[0], ast.Eq) and
@@ -152,6 +157,8 @@ def visit_If(
     ):
         if node.orelse and not isinstance(node.orelse[0], ast.If):
             yield ast_to_offset(node), _fix_py2_block
+        elif node.col_offset == 0 and not node.orelse:
+            yield ast_to_offset(node), _fix_remove_block
     elif (
             # if six.PY3:
             is_name_attr(

tests/features/versioned_branches_test.py

@@ -9,10 +9,7 @@
 @pytest.mark.parametrize(
     's',
     (
-        # we timidly skip `if` without `else` as it could cause a SyntaxError
-        'if six.PY2:\n'
-        '    pass',
-        # here's the case where it causes a SyntaxError
+        # skip `if` without `else` as it could cause a SyntaxError
         'if True:\n'
         '    if six.PY2:\n'
         '        pass\n',
@@ -570,6 +567,16 @@ def test_fix_py3_only_code(s, expected):
             'pass',
             id='sys.version_info >= (3, 6), noelse',
         ),
+        pytest.param(
+            'print("before")\n'
+            'if six.PY2:\n'
+            '    pass\n'
+            'print("after")\n',
+
+            'print("before")\n'
+            'print("after")\n',
+            id='can remove no-else if at module scope',
+        ),
     ),
 )
 def test_fix_py3x_only_code(s, expected):