Do not use punycode to encode or decode the local-part of an addr-spec.

Fixes issue #1012

Author: jstedfast

MimeKit/InternetAddress.cs

@@ -367,9 +367,6 @@ internal static bool TryParseLocalPart (byte[] text, ref int index, int endIndex
 
 			localpart = token.ToString ();
 
-			if (ParseUtils.IsIdnEncoded (localpart))
-				localpart = MailboxAddress.IdnMapping.Decode (localpart);
-
 			return true;
 		}
 

MimeKit/MailboxAddress.cs

@@ -307,17 +307,12 @@ static string EncodeAddrspec (string addrspec, int at)
 		{
 			if (at != -1) {
 				var domainEncoded = ParseUtils.IsInternational (addrspec, at + 1);
-				var localEncoded = ParseUtils.IsInternational (addrspec, 0, at);
 
-				if (!localEncoded && !domainEncoded)
+				if (!domainEncoded)
 					return addrspec;
 
-				string local, domain;
-
-				if (localEncoded)
-					local = IdnMapping.Encode (addrspec, 0, at);
-				else
-					local = addrspec.Substring (0, at);
+				var local = addrspec.Substring (0, at);
+				string domain;
 
 				if (domainEncoded)
 					domain = IdnMapping.Encode (addrspec, at + 1);

UnitTests/MailboxAddressTests.cs

@@ -656,27 +656,23 @@ public void TestGetAddress ()
 
 			mailbox = new MailboxAddress ("Unit Test", "點看@domain.com");
 			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@domain.com"), "IDN-decode #1");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (idn.GetAscii ("點看") + "@domain.com"), "IDN-encode #1");
-
-			mailbox = new MailboxAddress ("Unit Test", idn.GetAscii ("點看") + "@domain.com");
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@domain.com"), "IDN-decode #2");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (idn.GetAscii ("點看") + "@domain.com"), "IDN-encode #2");
+			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("點看@domain.com"), "IDN-encode #1");
 
 			mailbox = new MailboxAddress ("Unit Test", "user@名がドメイン.com");
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("user@名がドメイン.com"), "IDN-decode #3");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("user@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #3");
+			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("user@名がドメイン.com"), "IDN-decode #2");
+			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("user@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #2");
 
 			mailbox = new MailboxAddress ("Unit Test", "user@" + idn.GetAscii ("名がドメイン.com"));
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("user@名がドメイン.com"), "IDN-decode #4");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("user@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #4");
+			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("user@名がドメイン.com"), "IDN-decode #3");
+			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("user@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #3");
 
 			mailbox = new MailboxAddress ("Unit Test", "點看@名がドメイン.com");
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@名がドメイン.com"), "IDN-decode #5");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (idn.GetAscii ("點看") + "@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #5");
+			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@名がドメイン.com"), "IDN-decode #4");
+			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("點看@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #4");
 
-			mailbox = new MailboxAddress ("Unit Test", idn.GetAscii ("點看") + "@" + idn.GetAscii ("名がドメイン.com"));
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@名がドメイン.com"), "IDN-decode #6");
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (idn.GetAscii ("點看") + "@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #6");
+			mailbox = new MailboxAddress ("Unit Test", "點看@" + idn.GetAscii ("名がドメイン.com"));
+			Assert.That (mailbox.GetAddress (false), Is.EqualTo ("點看@名がドメイン.com"), "IDN-decode #5");
+			Assert.That (mailbox.GetAddress (true), Is.EqualTo ("點看@" + idn.GetAscii ("名がドメイン.com")), "IDN-encode #5");
 		}
 
 		[Test]
@@ -694,12 +690,6 @@ public void TestIsInternational ()
 			encoded = mailbox.ToString (options, true);
 			Assert.That (encoded, Is.EqualTo ("Unit Test <點看@domain.com>"), "ToString local-part");
 
-			// Test IsInternational IDN-encoded local-parts
-			mailbox = new MailboxAddress ("Unit Test", idn.GetAscii ("點看") + "@domain.com");
-			Assert.That (mailbox.IsInternational, Is.True, "IsInternational IDN-encoded local-part");
-			encoded = mailbox.ToString (options, true);
-			Assert.That (encoded, Is.EqualTo ("Unit Test <點看@domain.com>"), "ToString IDN-encoded local-part");
-
 			// Test IsInternational domain
 			mailbox = new MailboxAddress ("Unit Test", "user@名がドメイン.com");
 			Assert.That (mailbox.IsInternational, Is.True, "IsInternational domain");
@@ -725,8 +715,6 @@ public void TestIsInternational ()
 		[Test]
 		public void TestIdnEncoding ()
 		{
-			const string userAscii = "[email protected]";
-			const string userUnicode = "點看@domain.com";
 			const string domainAscii = "[email protected]";
 			const string domainUnicode = "user@名がドメイン.com";
 			MailboxAddress mailbox;
@@ -744,20 +732,6 @@ public void TestIdnEncoding ()
 			encoded = MailboxAddress.DecodeAddrspec (domainAscii);
 			Assert.That (encoded, Is.EqualTo (domainUnicode), "Domain (Decode)");
 
-			encoded = MailboxAddress.EncodeAddrspec (userUnicode);
-			Assert.That (encoded, Is.EqualTo (userAscii), "Local-part (Encode)");
-
-			encoded = MailboxAddress.DecodeAddrspec (userAscii);
-			Assert.That (encoded, Is.EqualTo (userUnicode), "Local-part (Decode)");
-
-			mailbox = new MailboxAddress (string.Empty, userAscii);
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (userAscii), "Ascii Local-part GetAddress(true)");
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo (userUnicode), "Ascii Local-part GetAddress(false)");
-
-			mailbox = new MailboxAddress (string.Empty, userUnicode);
-			Assert.That (mailbox.GetAddress (true), Is.EqualTo (userAscii), "Unicode Local-part GetAddress(true)");
-			Assert.That (mailbox.GetAddress (false), Is.EqualTo (userUnicode), "Unicode Local-part GetAddress(false)");
-
 			mailbox = new MailboxAddress (string.Empty, domainAscii);
 			Assert.That (mailbox.GetAddress (true), Is.EqualTo (domainAscii), "Ascii Domain GetAddress(true)");
 			Assert.That (mailbox.GetAddress (false), Is.EqualTo (domainUnicode), "Ascii Domain GetAddress(false)");