Bug#13639125 DELIMITER STRIPS THE NEXT NEW LINE

IN A SQL STATEMENT

While processing each lines entered at the prompt,
mysql client appends a '\n' to all the lines except
for delimiter commands. However the same logic must
not apply if 'delimiter' is part of a string or a
comment, for which a '\n' should be added.

Fixed by adding appropriate checks.

Added a test case.

client/mysql.cc

@@ -2283,17 +2283,19 @@ static bool add_line(String &buffer,char *line,char *in_string,
   {
     uint length=(uint) (out-line);
 
-    if (!truncated &&
-        (length < 9 || 
-         my_strnncoll (charset_info, 
-                       (uchar *)line, 9, (const uchar *) "delimiter", 9)))
+    if (!truncated && (length < 9 ||
+                       my_strnncoll (charset_info, (uchar *)line, 9,
+                                     (const uchar *) "delimiter", 9) ||
+                       (*in_string || *ml_comment)))
     {
       /* 
         Don't add a new line in case there's a DELIMITER command to be 
         added to the glob buffer (e.g. on processing a line like 
         "<command>;DELIMITER <non-eof>") : similar to how a new line is 
         not added in the case when the DELIMITER is the first command 
-        entered with an empty glob buffer. 
+        entered with an empty glob buffer. However, if the delimiter is
+        part of a string or a comment, the new line should be added. (e.g.
+        SELECT '\ndelimiter\n';\n)
       */
       *out++='\n';
       length++;