Bug#33812: mysql client incorrectly parsing DELIMITER

Revert fix for this bug as it introduced a regression
reported in Bug#38158.

client/mysql.cc

@@ -2081,6 +2081,37 @@ 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

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

mysql-test/t/mysql_delimiter.sql

@@ -60,12 +60,6 @@ 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