I18N: avoid trying to downconvert all-ascii domain names.

With the IDNA-2008 handling downconversion results in lowercasing;
so avoid doing that if possible.

diff --git a/src/src/utf8.c b/src/src/utf8.c
index be5bcb0788176a22bc884502fda86a9ad2a5a27d..e8690fc39da290006dbd5f7448780ebc88181d67 100644 (file)
--- a/src/src/utf8.c
+++ b/src/src/utf8.c
@@ -52,6 +52,10 @@ uschar * s1, * s;
 int rc;
 
 #ifdef SUPPORT_I18N_2008
+/* Avoid lowercasing plain-ascii domains */
+if (!string_is_utf8(utf8))
+  return string_copy(utf8);
+
 /* Only lowercase is accepted by the library call.  A pity since we lose
 any mixed-case annotation.  This does not really matter for a domain. */
   {