MDEV-31194: Server crash or assertion failure with join_cache_level=4

The problem, introduced in patch for MDEV-26301:

When check_join_cache_usage() decides not to use join buffer, it must
adjust the access method accordingly. For BNL-H joins this means switching
from pseudo-"ref access"(with index=MAX_KEY) to some other access method.

Failing to do this will cause assertions down the line when code that is
not aware of BNL-H will try to initialize index use for ref access with
index=MAX_KEY.

The fix is to follow the regular code path to disable the join buffer for
the join_tab ("goto no_join_cache") instead of just returning from
check_join_cache_usage().

mysql-test/main/derived_split_innodb.result

@@ -794,4 +794,20 @@ a	b	a	b	a	b	grp_id	count(*)
 5	5	5	2	5	3	5	100
 drop table t1,t2,t3;
 drop table t10, t11;
+#
+# MDEV-31194: Server crash or assertion failure with join_cache_level=4
+# (a followup to the above bug, MDEV-26301)
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (3),(4);
+CREATE TABLE t2 (id INT PRIMARY KEY) ENGINE=Aria;
+INSERT INTO t2 VALUES (1),(2);
+set @tmp1= @@optimizer_switch, @tmp2= @@join_cache_level;
+set
+optimizer_switch= 'derived_with_keys=off',
+join_cache_level= 4;
+SELECT t1.* FROM t1 JOIN (SELECT id, COUNT(*) FROM t2 GROUP BY id) sq ON sq.id= t1.a;
+a
+set optimizer_switch= @tmp1, join_cache_level= @tmp2;
+DROP TABLE t1, t2;
 # End of 10.4 tests

mysql-test/main/derived_split_innodb.test

@@ -439,4 +439,27 @@ eval $q;
 drop table t1,t2,t3;
 drop table t10, t11;
 
+
+--echo #
+--echo # MDEV-31194: Server crash or assertion failure with join_cache_level=4
+--echo # (a followup to the above bug, MDEV-26301)
+--echo #
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (3),(4);
+
+CREATE TABLE t2 (id INT PRIMARY KEY) ENGINE=Aria;
+INSERT INTO t2 VALUES (1),(2);
+
+set @tmp1= @@optimizer_switch, @tmp2= @@join_cache_level;
+set
+  optimizer_switch= 'derived_with_keys=off',
+  join_cache_level= 4;
+
+SELECT t1.* FROM t1 JOIN (SELECT id, COUNT(*) FROM t2 GROUP BY id) sq ON sq.id= t1.a;
+
+set optimizer_switch= @tmp1, join_cache_level= @tmp2;
+
+# Cleanup
+DROP TABLE t1, t2;
+
 --echo # End of 10.4 tests

sql/sql_select.cc

@@ -12873,7 +12873,7 @@ uint check_join_cache_usage(JOIN_TAB *tab,
   join->return_tab= 0;
 
   if (tab->no_forced_join_cache)
-    return 0;
+    goto no_join_cache;
 
   /*
     Don't use join cache if @@join_cache_level==0 or this table is the first