Since extending a class means including on the singleton class of the
class, this should now complain this:

``` ruby
module M
  extend Gitlab::Utils::Override

  override :f
  def f
    super.succ
  end
end

class C
  extend M

  def self.f
    0
  end
end
```

It should complain because `C.f` wasn't calling `M#f`.
This should pass verification:

``` ruby
module M
  extend Gitlab::Utils::Override

  override :f
  def f
    super.succ
  end
end

class B
  def self.f
    0
  end
end

class C < B
  extend M
end
```

Because `C.f` would now call `M#f`, and `M#f` does override something.

This currently causes 500's errors when loading the MR page
(Discussion) in a few scenarios.

We were not considering detailed diff headers such as
"--- a/doc/update/mysql_to_postgresql.md\n+++ b/doc/update/mysql_to_postgresql.md"
to crop the diff. In order to address it, we're now using
Gitlab::Diff::Parser, clean the diffs and builds Gitlab::Diff::Line objects
we can iterate and filter on.

When importing a GitHub pull request we would perform all work in a
single database transaction. This is less than ideal, because we perform
various slow Git operations when creating a merge request. This in turn
can lead to many DB connections being used, while just waiting for an IO
operation to complete.

To work around this, we now move most of the heavy lifting out of the
database transaction. Some extra error handling is added to ensure we
can resume importing a partially imported pull request, instead of just
throwing an error.

This commit also changes the specs for IssueImporter so they don't rely
on deprecated RSpec methods.

There was a race condition in the spec where if the commit is created on disk
within a second of the frozen `Timecop` time, the test fails.

Closes #43981

Signed-off-by: NRémy Coutable <remy@rymai.me>

* Replace `require` or `require_relative` with `require_dependency`
* Remove unneeded `autoload`

This mimics the same thing the RailsQueueDuration does for Rails controller
requests and will help diagnose issues with API delays.

Closes #46601

This commit does a number of things:

1. Reduces the number of queries needed by perform a single query to get all
the tuples for the relevant rows.

2. Uses a transaction to query the tuple counts to ensure that the data
is retrieved from the primary.

Closes #46742

We request Gitaly in a N+1 manner to build discussion diffs. Once the diffs are from different revisions, it's hard to make a single request to the service in order to build the whole response.
With this change we solve this problem and simplify a lot fetching this piece of info.

This will make it clearer to users which account is being used to make
the API/git call. So they know which account needs to be used to
accept the terms.

Closes #46649

For these kind of issues, the "reporter" field is present but zero.
In such a case, "fetch" will not return the default value, but it will
return nil.
Hence, importing fails, because the "username" field of nil is referenced

Fixes issue #44381

Signed-off-by: NRémy Coutable <remy@rymai.me>

Signed-off-by: NRémy Coutable <remy@rymai.me>