Remove extraneous parenthesis around keys in dict literals

(Commit adapted from PR #171.)

astor/code_gen.py

@@ -852,6 +852,7 @@ def visit_Dict(self, node):
         with self.delimit('{}'):
             for idx, (key, value) in enumerate(zip(node.keys, node.values)):
                 if key:
+                    set_precedence(Precedence.Comma, key)
                     set_precedence(Precedence.Comma, value)
                 self.write(', ' if idx else '',
                            key if key else '',

docs/changelog.rst

@@ -46,6 +46,14 @@ Bug fixes
 
 .. _`PR 202`: https://github.com/berkerpeksag/astor/pull/202
 
+* Remove extraneous parenthesis around keys in :class:`dict` literals. Astor
+  will now convert ``{(1): 2}`` and ``{(3 + 4): 5}`` to ``{1: 2}`` and
+  ``{3 + 4: 5}`` respectively.
+
+  (Contributed by Venkatesh-Prasad Ranganath in `PR 171`_.)
+
+.. _`PR 170`: https://github.com/berkerpeksag/astor/pull/171
+
 0.8.1 - 2019-12-10
 ------------------
 

tests/test_code_gen.py

@@ -1112,6 +1112,41 @@ def test_type_alias(self):
         '''
         self.assertSrcRoundtrips(source)
 
+    def test_do_not_add_excessive_parenthesis_in_keys_of_dict_literals(self):
+        source = 'spam = {(3):4}'
+        target = 'spam = {3: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {3:4}'
+        target = 'spam = {3: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {(3.0):4}'
+        target = 'spam = {3.0: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {3.0:4}'
+        target = 'spam = {3.0: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {(3+4):4}'
+        target = 'spam = {3 + 4: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {3+4:4}'
+        target = 'spam = {3 + 4: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
+
+        source = 'spam = {(3).foo:4}'
+        target = 'spam = {(3).foo: 4}'
+        astor.to_source(ast.parse(source))
+        self.assertAstEqualsSource(ast.parse(source), target)
 
 if __name__ == '__main__':
     unittest.main()