back-port from 5.1.

Bug#33812: mysql client incorrectly parsing DELIMITER
      
Remove unnecessary and incorrect code that tried
to pull delimiter commands out of the middle of
statements.

client/mysql.cc

@@ -2081,37 +2081,6 @@ static bool add_line(String &buffer,char *line,char *in_string,
 	continue;
       }
     }
-    else if (!*ml_comment && !*in_string &&
-             (end_of_line - pos) >= 10 &&
-             !my_strnncoll(charset_info, (uchar*) pos, 10,
-                           (const uchar*) "delimiter ", 10))
-    {
-      // Flush previously accepted characters
-      if (out != line)
-      {
-        buffer.append(line, (uint32) (out - line));
-        out= line;
-      }
-
-      // Flush possible comments in the buffer
-      if (!buffer.is_empty())
-      {
-        if (com_go(&buffer, 0) > 0) // < 0 is not fatal
-          DBUG_RETURN(1);
-        buffer.length(0);
-      }
-
-      /*
-        Delimiter wants the get rest of the given line as argument to
-        allow one to change ';' to ';;' and back
-      */
-      buffer.append(pos);
-      if (com_delimiter(&buffer, pos) > 0)
-        DBUG_RETURN(1);
-
-      buffer.length(0);
-      break;
-    }
     else if (!*ml_comment && !*in_string && is_prefix(pos, delimiter))
     {
       // Found a statement. Continue parsing after the delimiter

mysql-test/r/mysql.result

@@ -38,6 +38,8 @@ t2
 t3
 Tables_in_test
 t1
+delimiter
+1
 _
 Test delimiter : from command line
 a

mysql-test/t/mysql_delimiter.sql

@@ -60,6 +60,12 @@ use test//
 show tables//
 delimiter ; # Reset delimiter
 
+#
+# Bug #33812: mysql client incorrectly parsing DELIMITER
+#
+select a as delimiter from t1
+delimiter ; # Reset delimiter
+
 #
 # Bug #36244: MySQL CLI doesn't recognize standalone -- as comment
 #             before DELIMITER statement