Prior to this change, this method was called add_namespace, which broke
the CRUD convention and made it harder to grep for what I was looking
for. Given the change was a find and replace kind of fix, this was
changed without opening an issue and on another feature branch.

If more dynamic calls are made to add_namespace, these could've been
missed which might lead to incorrect bahaviour. However, going through
the commit log it seems thats not the case.

Part of the migration as tracked in: gitlab-org/gitaly#1026

A field didn't call the needed encoding helper, thus some UTF-8 encoding
couldn't be encoded to ASCII. Using the helper method this was fixed.

Tests are now run against Gitaly and Rugged too, to ensure both remain
working correctly.

Fixes gitlab-org/gitaly#1032, gitlab-org/gitlab-ce#43278

These are obscuring the real error, which is confusing for everyone.

Adds a test where a branch name is also a valid commit id. Git, the
binary should create an error message which is difficult to parse and
leading to errors later, as seen in: gitlab-org/gitlab-ce#43222

To catch these cases in the future,
gitlab-test@1942eed5cc108b19c7405106e81fa96125d0be22 was created. Which
a branch name matching the commit

26039 - add merge request id


26039 change due to lingust source file updates

We need to ignore the names for renamed files when configuring with sparse
checkout.

When the applied diff contains UTF-8 or some other encoded data, the diff
returned back from the git process may be in ASCII-8BIT format. Writing this
data to stdin may fail if the data because stdin expects this data to be in
UTF-8. By switching the output to binmode, we ensure that the diff will
always be written as-is.

Closes gitlab-org/gitlab-ee#4960

The refs hash is used to determine what branches and tags have a commit
as head in the network graph. The previous implementation depended on
Rugged#references. The problem with this implementation was that it
depended on rugged, but also that it iterated over all references and
thus loading more data than needed if for example the project uses CI/CD
environments, Pipelines, or Merge Requests.

Given only refs are checked the network cares about the GraphHelper#refs
method has no need to reject those, simplifying the method.

Closes gitlab-org/gitaly#880

Gitlab::Git::Repository#find_branch has a similar logic.

Fixes #42609

This was affecting the performance of `Gitlab::Git::Repository#squash`.

- Add tests for Repository#write_config

Closes gitaly#967

This reverts merge request !16525

Closes gitaly#946

Closes gitaly#929

Closes gitaly#851

By importing this Ruby code into gitlab-rails (and gitaly-ruby), we avoid
200ms of startup time for each gitlab_projects subprocess we are eliminating.

By not having a gitlab_projects subprocess between gitlab-rails / sidekiq and
any git subprocesses (e.g. for fork_project, fetch_remote, etc, calls), we can
also manage these git processes more cleanly, and avoid sending SIGKILL to them