MDEV-8392: Couldn't alter field with default value for make it not nullable.

Analysis; Problem is that InnoDB does not have support for generating
CURRENT_TIMESTAMP or constant default.

Fix: Add additional check if column has changed from NULL -> NOT NULL
and column default has changed. If this is is first column definition
whose SQL type is TIMESTAMP and it is defined as NOT NULL and
it has either constant default or function default we must use
"Copy" method for alter table.

1 files changed, 29 insertions, 0 deletions

diff --git a/mysql-test/suite/innodb/r/innodb-alter-timestamp.result b/mysql-test/suite/innodb/r/innodb-alter-timestamp.result
new file mode 100644
index 00000000000..2ab81136d1f
--- /dev/null
+++ b/mysql-test/suite/innodb/r/innodb-alter-timestamp.result
@@ -0,0 +1,29 @@
+CREATE TABLE t1 (
+`i1` INT(10) UNSIGNED NOT NULL,
+`d1` TIMESTAMP NULL DEFAULT NULL
+) ENGINE=innodb;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `i1` int(10) unsigned NOT NULL,
+  `d1` timestamp NULL DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+INSERT INTO t1 (i1) VALUES (1), (2), (3), (4), (5);
+select * from t1;
+i1	d1
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+5	NULL
+set sql_mode = 'STRICT_ALL_TABLES,NO_ZERO_DATE';
+ALTER TABLE t1 CHANGE `d1` `d1` TIMESTAMP DEFAULT CURRENT_TIMESTAMP  NOT NULL;
+drop table t1;
+CREATE TABLE t1 (
+`i1` INT(10) UNSIGNED NOT NULL,
+`d1` TIMESTAMP NULL DEFAULT NULL
+) ENGINE=innodb;
+INSERT INTO t1 (i1) VALUES (1), (2), (3), (4), (5);
+ALTER TABLE t1 CHANGE `d1` `d1` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP;
+drop table t1;
+set sql_mode = '';