#12818: remove escaping of () in quoted strings in formataddr

The quoting of ()s inside quoted strings is allowed by the RFC, but is not
needed.  There seems to be no reason to add needless escapes.

Lib/email/utils.py

@@ -55,7 +55,7 @@ CRLF = '\r\n'
 TICK = "'"
 
 specialsre = re.compile(r'[][\\()<>@,:;".]')
-escapesre = re.compile(r'[][\\()"]')
+escapesre = re.compile(r'[\\"]')
 
 
 

Lib/test/test_email/test_email.py

@@ -2702,7 +2702,10 @@ class TestMiscellaneous(TestEmailBase):
     def test_escape_dump(self):
         self.assertEqual(
             utils.formataddr(('A (Very) Silly Person', 'person@dom.ain')),
-            r'"A \(Very\) Silly Person" <person@dom.ain>')
+            r'"A (Very) Silly Person" <person@dom.ain>')
+        self.assertEqual(
+            utils.parseaddr(r'"A \(Very\) Silly Person" <person@dom.ain>'),
+            ('A (Very) Silly Person', 'person@dom.ain'))
         a = r'A \(Special\) Person'
         b = 'person@dom.ain'
         self.assertEqual(utils.parseaddr(utils.formataddr((a, b))), (a, b))
@@ -2800,6 +2803,15 @@ class TestMiscellaneous(TestEmailBase):
         self.assertEqual(('', 'merwok.wok.wok@xample.com'),
             utils.parseaddr('merwok. wok .  wok@xample.com'))
 
+    def test_formataddr_does_not_quote_parens_in_quoted_string(self):
+        addr = ("'foo@example.com' (foo@example.com)",
+                'foo@example.com')
+        addrstr = ('"\'foo@example.com\' '
+                            '(foo@example.com)" <foo@example.com>')
+        self.assertEqual(utils.parseaddr(addrstr), addr)
+        self.assertEqual(utils.formataddr(addr), addrstr)
+
+
     def test_multiline_from_comment(self):
         x = """\
 Foo

Misc/NEWS

@@ -24,6 +24,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #12818: format address no longer needlessly \ escapes ()s in names when
+  the name ends up being quoted.
+
 - Issue #14062: BytesGenerator now correctly folds Header objects,
   including using linesep when folding.