Merge pull request #4 from asottile/parenthesized_function

Properly detect parens when the function is parenthesized

add_trailing_comma.py

@@ -179,13 +179,16 @@ def _fix_call(call, i, tokens):
     #
     #     func_name(arg, arg, arg)
     #              ^ outer paren
+    brace_start, brace_end = '(', ')'
     first_paren = None
     paren_stack = []
     for i in range(i, len(tokens)):
         token = tokens[i]
-        if token.src == '(':
+        if token.src == brace_start:
             paren_stack.append(i)
-        elif token.src == ')':
+        # the ast lies to us about the beginning of parenthesized functions.
+        # See #3. (why we make sure there's something to pop here)
+        elif token.src == brace_end and paren_stack:
             paren_stack.pop()
 
         if (token.line, token.utf8_byte_offset) in call.arg_offsets:
@@ -194,7 +197,7 @@ def _fix_call(call, i, tokens):
     else:
         raise AssertionError('Past end?')
 
-    _fix_inner('(', ')', first_paren, tokens)
+    _fix_inner(brace_start, brace_end, first_paren, tokens)
 
 
 def _fix_literal(literal, i, tokens):

tests/add_trailing_comma_test.py

@@ -42,6 +42,10 @@ xfailif_lt_py35 = pytest.mark.xfail(sys.version_info < (3, 5), reason='py35+')
         'x((\n'
         '    1,\n'
         '))',
+        # regression test for #3
+        '(\n'
+        '    a\n'
+        ').f(b)',
     ),
 )
 def test_fix_calls_noops(src):