MDEV-6603 SBR failure upon executing a prepared statement with input placeholder under anonymous block

Normally, Prepared_statement object rewrites the query on execution
to replace ?-placeholders with values. The rewritten query may be written
to logs (including binlog) or stored in the query cache.

But for compound statements, the whole block is prepared and executed,
while contained statements are logged individually. So it doesn't make
sense to rewrite the original statement block. Instead, we need to rewrite
every contained statement. SP is already doing it to replace SP variables
with values. Let it rewrite PS parameters too in the same loop.

mysql-test/r/compound.result

@@ -15,6 +15,7 @@ PREPARE stmt FROM "BEGIN NOT ATOMIC
   INSERT INTO t1 VALUES (?);
 END";
 SET @val = 6|
+reset master|
 EXECUTE stmt USING @val|
 SELECT * FROM t1|
 a
@@ -24,6 +25,17 @@ a
 4
 5
 6
+include/show_binlog_events.inc
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO t1 VALUES (4)
+master-bin.000001	#	Query	#	#	COMMIT
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO t1 VALUES (5)
+master-bin.000001	#	Query	#	#	COMMIT
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; INSERT INTO t1 VALUES (6)
+master-bin.000001	#	Query	#	#	COMMIT
 PREPARE stmt FROM "BEGIN NOT ATOMIC
   DECLARE v_res INT;
   SELECT COUNT(*) INTO v_res FROM t1;
@@ -119,3 +131,35 @@ executing:	drop table t1
 executing:	drop table t2
 executing:	drop table t3
 executing:	drop table t4
+create table t1 (x int)|
+create function fn(a int) returns int
+begin
+insert t1 values (a+7);
+return a+8;
+end|
+reset master|
+/**/ if fn(9) > 5 then
+select 1;
+end if|
+1
+1
+prepare stmt from "if fn(?) > 6 then
+ begin
+  declare a int;
+  set a=?*2;
+  insert t1 values(a+?);
+ end;
+end if"|
+set @a=1, @b=2, @c=3|
+execute stmt using @a, @b, @c|
+include/show_binlog_events.inc
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Gtid	#	#	GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; SELECT "test"."fn"(9)
+master-bin.000001	#	Gtid	#	#	GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; SELECT "test"."fn"(1)
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; insert t1 values( NAME_CONST('a',4)+3)
+master-bin.000001	#	Query	#	#	COMMIT
+drop function fn|
+drop table t1|

mysql-test/t/compound.test

@@ -1,6 +1,7 @@
 #
 # MDEV-5317 Compound statement / anonymous blocks
 #
+source include/have_log_bin.inc;
 delimiter |;
 
 CREATE TABLE t1 (a INT PRIMARY KEY)|
@@ -18,9 +19,15 @@ PREPARE stmt FROM "BEGIN NOT ATOMIC
   INSERT INTO t1 VALUES (?);
 END";
 SET @val = 6|
+reset master|
 EXECUTE stmt USING @val|
 SELECT * FROM t1|
 
+# see how ?-placeholder was replaced with the value
+delimiter ;|
+source include/show_binlog_events.inc;
+delimiter |;
+
 PREPARE stmt FROM "BEGIN NOT ATOMIC
   DECLARE v_res INT;
   SELECT COUNT(*) INTO v_res FROM t1;
@@ -113,3 +120,31 @@ do
   execute dt;
 end while|
 --horizontal_results
+
+# see how ?-placeholder and SP variables are replaced with values
+create table t1 (x int)|
+create function fn(a int) returns int
+begin
+  insert t1 values (a+7);
+  return a+8;
+end|
+reset master|
+/**/ if fn(9) > 5 then
+  select 1;
+end if|
+prepare stmt from "if fn(?) > 6 then
+ begin
+  declare a int;
+  set a=?*2;
+  insert t1 values(a+?);
+ end;
+end if"|
+set @a=1, @b=2, @c=3|
+execute stmt using @a, @b, @c|
+delimiter ;|
+source include/show_binlog_events.inc;
+delimiter |;
+
+drop function fn|
+drop table t1|
+

sql/sp_head.cc

@@ -890,7 +890,8 @@ sp_head::create_result_field(uint field_max_length, const char *field_name,
 }
 
 
-int cmp_splocal_locations(Item_splocal * const *a, Item_splocal * const *b)
+int cmp_rqp_locations(Rewritable_query_parameter * const *a,
+                      Rewritable_query_parameter * const *b)
 {
   return (int)((*a)->pos_in_query - (*b)->pos_in_query);
 }
@@ -996,30 +997,29 @@ subst_spvars(THD *thd, sp_instr *instr, LEX_STRING *query_str)
 {
   DBUG_ENTER("subst_spvars");
 
-  Dynamic_array<Item_splocal*> sp_vars_uses;
+  Dynamic_array<Rewritable_query_parameter*> rewritables;
   char *pbuf;
   StringBuffer<512> qbuf;
   Copy_query_with_rewrite acc(thd, query_str->str, query_str->length, &qbuf);
 
-  /* Find all instances of Item_splocal used in this statement */
+  /* Find rewritable Items used in this statement */
   for (Item *item= instr->free_list; item; item= item->next)
   {
-    Item_splocal *item_spl= item->get_item_splocal();
-    if (item_spl && item_spl->pos_in_query)
-      sp_vars_uses.append(item_spl);
+    Rewritable_query_parameter *rqp= item->get_rewritable_query_parameter();
+    if (rqp && rqp->pos_in_query)
+      rewritables.append(rqp);
   }
-  if (!sp_vars_uses.elements())
+  if (!rewritables.elements())
     DBUG_RETURN(FALSE);
 
-  /* Sort SP var refs by their occurences in the query */
-  sp_vars_uses.sort(cmp_splocal_locations);
+  rewritables.sort(cmp_rqp_locations);
 
-  thd->query_name_consts= sp_vars_uses.elements();
+  thd->query_name_consts= rewritables.elements();
 
-  for (Item_splocal **splocal= sp_vars_uses.front(); 
-       splocal <= sp_vars_uses.back(); splocal++)
+  for (Rewritable_query_parameter **rqp= rewritables.front();
+       rqp <= rewritables.back(); rqp++)
   {
-    if (acc.append(*splocal))
+    if (acc.append(*rqp))
       DBUG_RETURN(TRUE);
   }
   if (acc.finalize())

sql/sql_prepare.cc

@@ -3235,6 +3235,8 @@ void Prepared_statement::setup_set_params()
   replace_params_with_values|= opt_log || thd->variables.sql_log_slow;
   // query cache
   replace_params_with_values|= query_cache_is_cacheable_query(lex);
+  // but never for compound statements
+  replace_params_with_values&= lex->sql_command != SQLCOM_COMPOUND;
 
   if (replace_params_with_values)
   {

sql/sql_yacc.yy

@@ -13333,7 +13333,9 @@ param_marker:
               my_error(ER_VIEW_SELECT_VARIABLE, MYF(0));
               MYSQL_YYABORT;
             }
-            item= new (thd->mem_root) Item_param((uint) (lip->get_tok_start() - thd->query()));
+            const char *query_start= lex->sphead ? lex->sphead->m_tmp_query
+                                                 : thd->query();
+            item= new (thd->mem_root) Item_param(lip->get_tok_start() - query_start);
             if (!($$= item) || lex->param_list.push_back(item))
             {
               my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));