pythongh-92671: Don't omit parentheses when unparsing empty tuples (pythonGH-92673)

Author: isidentical

Lib/ast.py

@@ -1335,7 +1335,11 @@ def write_item(item):
             )
 
     def visit_Tuple(self, node):
-        with self.require_parens(_Precedence.TUPLE, node):
+        with self.delimit_if(
+            "(",
+            ")",
+            len(node.elts) == 0 or self.get_precedence(node) > _Precedence.TUPLE
+        ):
             self.items_view(self.traverse, node.elts)
 
     unop = {"Invert": "~", "Not": "not", "UAdd": "+", "USub": "-"}

Lib/test/test_unparse.py

@@ -648,6 +648,9 @@ def test_star_expr_assign_target(self):
                     self.check_src_roundtrip(source.format(target=target))
 
     def test_star_expr_assign_target_multiple(self):
+        self.check_src_roundtrip("() = []")
+        self.check_src_roundtrip("[] = ()")
+        self.check_src_roundtrip("() = [a] = c, = [d] = e, f = () = g = h")
         self.check_src_roundtrip("a = b = c = d")
         self.check_src_roundtrip("a, b = c, d = e, f = g")
         self.check_src_roundtrip("[a, b] = [c, d] = [e, f] = g")

Misc/NEWS.d/next/Library/2022-05-11-19-33-27.gh-issue-92671.KE4v6a.rst

@@ -0,0 +1 @@
+Fixed :func:`ast.unparse` for empty tuples in the assignment target context.