Submitted by: @mrotteveel

The COMMENT ON USER statement can only put comments on users of the default usermanager. The syntax should be extended to include an optional USING PLUGIN <pluginname> clause. For example `COMMENT ON USER x USING PLUGIN pluginname IS 'comment'`

With setting UserManager = Srp,Legacy_UserManager.

create user test1 password 'test1' using plugin srp;
create user test2 password 'test2' using plugin legacy_usermanager;

commit;

The following will succeed:

comment on user test1 is 'comment on user test1';

The following will fail:

comment on user test2 is `comment on user test2';

[336723990] [HY000]: Resource Exception. record not found for user: TEST2

Commits: 8dfaf3a f9b7cd5

====== Test Details ======

There is no sense to check for Legacy_UserManarer: comment for user will not be stored in the sec$users for this plugin.
Test verifies only Srp.