[ci skip]

[ci skip]

Fix #33441

This reduces the time spent waiting for Sidekiq jobs to complete in
JobWaiter, and reduces the sleep interval when trying to acquire the
lease for refreshing authorizations. These changes should reduce the
time spent just waiting for a lock, which we seem to be spending most
time in when running the AuthorizedProjectsWorker.

Submodules have a name in the configuration, but this name is simply
the path at which the submodule was initially checked in (by default
-- the name is totally arbitrary).  If a submodule is moved, it
retains its original name, but its path changes.  Since we discover
submodules inside trees, we have their path but not necessarily their
name.

Make the submodules() function return the submodule hash indexed by
path rather than name, so that renamed submodules can be looked up.
Signed-off-by: NDavid Turner <novalis@novalis.org>

This changes ProjectsFinder#init_collection so it no longer relies on a
UNION. For example, to get starred projects of a user we used to run:

    SELECT projects.*
    FROM projects
    WHERE projects.pending_delete = 'f'
    AND (
        projects.id IN (
            SELECT projects.id
            FROM projects
            INNER JOIN users_star_projects
                ON users_star_projects.project_id = projects.id
            INNER JOIN project_authorizations
                ON projects.id = project_authorizations.project_id
            WHERE projects.pending_delete = 'f'
            AND project_authorizations.user_id = 1
            AND users_star_projects.user_id = 1

            UNION

            SELECT projects.id
            FROM projects
            INNER JOIN users_star_projects
                ON users_star_projects.project_id = projects.id
            WHERE projects.visibility_level IN (20, 10)
            AND users_star_projects.user_id = 1
        )
    )
    ORDER BY projects.id DESC;

With these changes the above query is turned into the following instead:

    SELECT projects.*
    FROM projects
    INNER JOIN users_star_projects
        ON users_star_projects.project_id = projects.id
    WHERE projects.pending_delete = 'f'
    AND (
        EXISTS (
            SELECT 1
            FROM project_authorizations
            WHERE project_authorizations.user_id = 1
            AND (project_id = projects.id)
        )
        OR projects.visibility_level IN (20,10)
    )
    AND users_star_projects.user_id = 1
    ORDER BY projects.id DESC;

This query in turn produces a better execution plan and takes less time,
though the difference is only a few milliseconds (this however depends
on the amount of data involved and additional conditions that may be
added).

We removed calls from our code to Rugged::Repository#fetch_attributes:
<https://gitlab.com/gitlab-org/gitlab_git/commit/340e111e040ae847b614d35b4d3173ec48329015>

However, we didn't remove calls from within Linguist. This method is only called
when calculating the languages for a repository on the Charts page:
<https://github.com/github/linguist/blob/v4.7.0/lib/linguist/lazy_blob.rb#L33-L36>

We can safely use our own Gitlab::Git::Attributes here. On staging, for the
GitLab CE repo, this makes the calculation take about a third of the time:

    # Before
    Benchmark.realtime do
      Linguist::Repository.new(repository.rugged,
                               repository.rugged.head.target_id).languages
    end
    #=> 23.67193900188431

    # After
    Benchmark.realtime do
      Linguist::Repository.new(repository.rugged,
                               repository.rugged.head.target_id).languages
    end
    #=> 8.945212290156633

[ci skip]

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/27070

Deprecate "chat commands" in favor of "slash commands"

We looked for things like:

 - `slash commmand`
 - `slash_command`
 - `slash-command`
 - `SlashCommand`