MDEV-29069 follow-up: improve DEFAULT rulesbb-10.11-oalter

previously, fields with DEFAULTs were allowed just when expression is
deterministic. In case of online alter, we should recursively check that
underlying fields of expression also either have explicit values, or
have DEFAULT following this validity rule.

1 files changed, 36 insertions, 0 deletions

diff --git a/mysql-test/main/alter_table_online_debug.test b/mysql-test/main/alter_table_online_debug.test
index 663a5293903..2062f1349b0 100644
--- a/mysql-test/main/alter_table_online_debug.test
+++ b/mysql-test/main/alter_table_online_debug.test
@@ -1270,6 +1270,42 @@ set debug_sync= 'now signal goforit';
 --reap
 
 
+--echo #
+--echo # Useful UNIQUE, though a virtual column on another extra field
+--echo #
+create or replace table t (a int primary key, b int default (a+1));
+insert into t values (10, 10),(20, 20),(30, 30);
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+--send
+alter table t drop primary key, add c int default(a),
+              add d int as (c) stored unique, algorithm=copy, lock=none;
+--connection con2
+set debug_sync= 'now wait_for downgraded';
+delete from t where a = 20;
+update t set a = a + 2 where a = 10;
+set debug_sync= 'now signal goforit';
+--connection default
+--reap
+select * from t;
+
+--echo #
+--echo # Now this index is not usable (missing DEFAULT on field c)
+--echo #
+create or replace table t (a int primary key, b int);
+insert into t values (10, 10),(20, 20),(30, 30);
+set debug_sync= 'alter_table_online_downgraded signal downgraded wait_for goforit';
+--send
+alter table t drop primary key, add c real default(rand(a)),
+              add d real as (c) stored unique, algorithm=copy, lock=none;
+--connection con2
+set debug_sync= 'now wait_for downgraded';
+delete from t where a = 20;
+update t set a = a + 2 where a = 10;
+set debug_sync= 'now signal goforit';
+--connection default
+--reap
+select a, b from t;
+
 # Cleanup
 drop table t;
 set debug_sync= reset;