If a user upgraded to any GitLab 11.x EE version but switched
back to CE, it's possible the state of the EE tables are not
in the right state for the EE backport migration to work properly.
In particular, there were three tables that had trouble:
* epics
* geo_event_log
* vulnerability_feedback
The EE backport migration would fail while trying to add foreign key
constraints because a key didn't exist in the table. This happens
because any EE migration that add or removed columns between v11.0.0 and
v11.11.3 are not guaranteed to be applied in an CE installation. The EE
backport schema does not individually backport these migrations.
We now check if certain columns are present to determine whether
the backport migration is in the proper state. CE users are required
to upgrade to v11.11.3 EE if they ever installed EE previously before
they can go back to v12.x CE.
Tested via:
```
git checkout -f v11.0.0-ee
bundle exec rake db:reset
git checkout .; git checkout -f v11.11.3
bundle exec rake db:migrate
git checkout .; git checkout -f v12.0.0
bundle exec rake db:migrate
<failure happens>
```
This backports all EE schema changes to CE, including EE migrations,
ensuring both use the same schema.
== Updated tests
A spec related to ghost and support bot users had to be modified to make
it pass. The spec in question assumes that the "support_bot" column
exists when defining the spec. In the single codebase setup this is not
the case, as the column is backported in a later migration. Any attempt
to use a different schema version or use of "around" blocks to
conditionally disable specs won't help, as reverting the backport
migration would also drop the "support_bot" column. Removing the
"support_bot" tests entirely appears to be the only solution.
We also need to update some foreign key tests now that we have
backported the EE columns. Fortunately, these changes are very minor.
== Backporting migrations
This commit moves EE specific migrations (except those for the Geo
tracking database) and related files to CE, and also removes any traces
of the ee/db directory.
Some migrations had to be modified or removed, as they no longer work
with the schema being backported. These migrations were all quite old,
so we opted for removing them where modifying them would take too much
time and effort.
Some old migrations were modified in EE, while also existing in CE. In
these cases we took the EE code, and in one case removed them entirely.
It's not worth spending time trying to merge these changes somehow as we
plan to remove old migrations around the release of 12.0, see
https://gitlab.com/gitlab-org/gitlab-ce/issues/59177 for more details.
GitLab Bot