Schema Generator touches nullable properties with each update

[jasperroloff]

Describe the bug
When generating a migration or running a schema upgrade directly, the schema generator alters the nullable properties of the entity each time.

Stack trace
The generated schema update is the following (even if executed already):

set names utf8;
set foreign_key_checks = 0;

alter table `foo_entity` modify `nullable_string_property` varchar(255), modify `nullable_boolean_property` tinyint(1), modify `nullable_number_property` int(11);

set foreign_key_checks = 1;

To Reproduce
I've created a sample repository. Use ts-node src/main.ts to run.
https://github.com/jasperroloff/mikro-orm-nullable-issue

Expected behavior
Since the entity didn't change, the schema generator should generate an empty update (without the "alter table ..." statements).

Additional context
I discovered this behavior with both metadata providers: TsMorph, ReflectMetadata and with both database drivers: mysql, mariadb.

Versions

Dependency	Version
node	v13.13.0
typescript	^3.8.3
mikro-orm	^3.6.8
mariadb	^2.3.1
mysql2	^2.1.0
ts-node	^8.8.2

(see package.json in sample repo)

[B4nan]

Well it does not produce any additional queries for me. What version of MySQL are you using (not the driver)? Maybe you use MySQL 8?

edit: it works ok for me even with MySQL 8. also tried to run it in the repo you provided, same result.

[jasperroloff]

Hi, thanks for your reply.

I am using MariaDB, select version() returns the following: 10.4.11-MariaDB.

Edit: I just tested it with MySQL 8.0.19 as server, I am getting the same result as you did (everything works as it should).
So it looks like this problem does only happen with MariaDB servers.

[B4nan]

Interesting, tried it with mariadb 10.1 first and it passed, but with 10.4 it does behave like you described.