sql_table.cc:

  Return a sensible error code from DISCARD TABLESPACE, if it fails because the table is referenced by a FOREIGN KEY


sql/sql_table.cc:
  Return a sensible error code from DISCARD TABLESPACE, if it fails because the table is referenced by a FOREIGN KEY

sql/sql_table.cc

@@ -2465,7 +2465,11 @@ err:
     send_ok(thd);
     DBUG_RETURN(0);
   }
-  DBUG_RETURN(error);
+
+  if (error == HA_ERR_ROW_IS_REFERENCED)
+    my_error(ER_ROW_IS_REFERENCED, MYF(0));
+  
+  DBUG_RETURN(-1);
 }