Fix for bug #9566 "explicit LOCK TABLE and store procedures result in

illegal state".

We should not assume that mysql.proc table does not exist if we are
unable to open it under LOCK TABLES or in prelocked mode (and
remember this fact by setting mysql_proc_table_exists to zero).

mysql-test/r/sp.result

@@ -2779,4 +2779,14 @@ a
 3.2000
 drop procedure bug8937|
 delete from t1|
+drop procedure if exists bug9566|
+create procedure bug9566()
+begin
+select * from t1;
+end|
+lock table t1 read|
+call bug9566()|
+ERROR HY000: Table 'proc' was not locked with LOCK TABLES
+unlock tables|
+drop procedure bug9566|
 drop table t1,t2;

mysql-test/t/sp.test

@@ -3397,6 +3397,29 @@ call bug8937()|
 drop procedure bug8937|
 delete from t1|
 
+#
+# BUG#9566: explicit LOCK TABLE and store procedures result in illegal state
+#
+# We should not think that mysql.proc table does not exist if we are unable
+# to open it under LOCK TABLE or in prelocked mode. Probably this test
+# should be removed when Monty will allow access to mysql.proc without
+# locking it.
+#
+--disable_warnings
+drop procedure if exists bug9566|
+--enable_warnings
+create procedure bug9566()
+begin
+  select * from t1;
+end|
+lock table t1 read|
+# This should fail because we forgot to lock mysql.proc table explicitly
+--error 1100
+call bug9566()|
+unlock tables|
+# This should succeed
+drop procedure bug9566|
+
 
 #
 # BUG#NNNN: New bug synopsis

sql/sp.cc

@@ -70,9 +70,8 @@ db_find_routine_aux(THD *thd, int type, sp_name *name,
 		       type, name->m_name.length, name->m_name.str));
 
   /*
-    Speed up things if mysql.proc doesn't exists
-    mysql_proc_table_exists is set when on creates a stored procedure
-    or on flush privileges
+    Speed up things if mysql.proc doesn't exists. mysql_proc_table_exists
+    is set when we create or read stored procedure or on flush privileges.
   */
   if (!mysql_proc_table_exists && ltype == TL_READ)
     DBUG_RETURN(SP_OPEN_TABLE_FAILED);
@@ -98,7 +97,13 @@ db_find_routine_aux(THD *thd, int type, sp_name *name,
     if (! (table= open_ltable(thd, &tables, ltype)))
     {
       *tablep= NULL;
-      mysql_proc_table_exists= 0;
+      /*
+        Under explicit LOCK TABLES or in prelocked mode we should not
+        say that mysql.proc table does not exist if we are unable to
+        open it since this condition may be transient.
+      */
+      if (!(thd->locked_tables || thd->prelocked_mode))
+        mysql_proc_table_exists= 0;
       DBUG_RETURN(SP_OPEN_TABLE_FAILED);
     }
     *opened= TRUE;