Bug#30632 HANDLER read failure causes hang

If, after the tables are locked, one of the conditions to read from a
HANDLER table is not met, the handler code wrongly jumps to a error path
that won't unlock the tables.

The user-visible effect is that after a error in a handler read command,
all subsequent handler operations on the same table will hang.

The fix is simply to correct the code to jump to the (same) error path that
unlocks the tables.


mysql-test/r/handler.result:
  Bug#30632 test case result
mysql-test/t/handler.test:
  Bug#30632 test case
sql/sql_handler.cc:
  Always unlock the internal and external table level locks if any of the conditions
  (including errors) to read from a HANDLER table are not met.

1 files changed, 3 insertions, 3 deletions

diff --git a/sql/sql_handler.cc b/sql/sql_handler.cc
index 83c141f099f..9aefa71647e 100644
--- a/sql/sql_handler.cc
+++ b/sql/sql_handler.cc
@@ -440,7 +440,7 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
       cond->cleanup();                          // File was reopened
     if ((!cond->fixed &&
 	 cond->fix_fields(thd, &cond)) || cond->check_cols(1))
-      goto err0;
+      goto err;
   }
 
   if (keyname)
@@ -448,13 +448,13 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
     if ((keyno=find_type(keyname, &table->s->keynames, 1+2)-1)<0)
     {
       my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), keyname, tables->alias);
-      goto err0;
+      goto err;
     }
   }
 
   if (insert_fields(thd, &thd->lex->select_lex.context,
                     tables->db, tables->alias, &it, 0))
-    goto err0;
+    goto err;
 
   protocol->send_fields(&list, Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF);