Extract diverging_commit_counts into a service class

This change makes sure Gitaly includes a fix to make rebase work again
properly.

Part of: https://gitlab.com/gitlab-org/gitlab-ce/issues/62353

Disabling because of https://gitlab.com/gitlab-org/gitlab-ce/issues/62353

If `merge_error` is ever set after a failure, it is never cleared, even
after a subsequent, successful rebase. We now clear this field whenever
a successful rebase occurs.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/56139

We want to optimize the query for the CountDivergingCommits rpc by
removing the --max-count argument now that we have commit graphs
enabled for all repositories during housekeeping. However, we want to
test this first behind a feature flag.

Fixes #60425

The new two-step Gitaly `Rebase` RPC yields the rebase commit SHA to the
client before proceeding with the rebase.

This avoids an issue where the rebase commit SHA was returned when the
RPC had fully completed, and in some cases this would be after the Rails
`post_receive` worker services had already run. In these situations,
the merge request did not yet have its rebase_commit_sha attribute set
introducing the possibility for bugs (such as previous approvals being
reset).

https://gitlab.com/gitlab-org/gitlab-ee/issues/5966

Updates the EnvironmentController#metrics_dashboard endpoint
to support a "dashboard" param, which can be used to specify
the filepath of a dashboard configuration from a project
repository. Dashboard configurations are expected to be
stored in .gitlab/dashboards/.

Updates dashboard post-processing steps to exclude custom
metrics, which should only display on the system dashboard.

This ports the changes from
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10462/
to CE

This reverts commit 171818df.

This reverts commit 6c75bd01, reversing
changes made to 1be7f5aa.

Add `GetArchiveRequest` to git-archive params.

Modifies `Git::Repository#archive_metadata` to append `path`
to `ArchivePrefix` so it'll not hit the cache of repository archive
when it already exists.

This changes the repository type from a binary `wiki?` to a type. So
we can have more than 2 repository types.

Now everywhere we called `.wiki?` and expected a boolean, we check
that type.

This reverts merge request !26183

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

When an empty project is loaded in the UI, there are 15 separate Gitaly
FindDefaultBranch calls to determine the root_ref. Previously, it was
not cached even within the request. This change caches it within the
request so only a single FindDefaultBranch RPC is needed.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/58684

This style change enforces `return if ...` instead of
`return nil if ...` to save maintainers a few minor review points

Adds the ground work for writing into
the merge ref refs/merge-requests/:iid/merge the
merge result between source and target branches of
a MR, without further side-effects such as
mailing, MR updates and target branch changes.

Adds the client call for the gitaly rpc CountDivergingCommits

fixing signature

simplifying commit logic

adding test for max-count

refactoring tests

When hashed storage is in use, it's helpful to have the project
name associated with the request.

Closes https://gitlab.com/gitlab-org/gitaly/issues/1394

This engine was replaced with CommonMarker in 11.4, it was deprecated
since then.

The data migration looks for code owner file and errs
if repository is missing.

This reverts commit e65e1842, reversing
changes made to 646ba241.

This implements Repository#ambiguous_ref? and checks if a ref is
ambiguous before trying to resolve the ref in Project#protected_for?

Reworks Project#resolve_ref to return Gitlab::Git::Branch,
Gitlab::Git::Tag or raise an AmbiguousRef error.

Determined by running the script:

```
included = `git grep --name-only ShellAdapter`.chomp.split("\n")
used = `git grep --name-only gitlab_shell`.chomp.split("\n")
included - used
```

Caches repository.path into Repository#readme_path

Use shelling out to git to write refs instead of rugged, hoping to
avoid creating invalid refs.

To update HEAD we switched to using `git symbolic-ref`.

This new endpoint allow users to update a submodule's reference.

The MR involves adding a new operation RPC operation in gitaly-proto
(see gitlab-org/gitaly-proto!233) and change Gitaly to use this
new version (see gitlab-org/gitaly!936).

See gitlab-org/gitlab-ce!20949

This indirection doesn't provide any value, so remove it

GitLab keeps a cache of the rendered HTML for a repository's README as
stored in the HEAD branch. However, it was not used in all
circumstances. In particular, the new blob viewer framework bypassed
this cache entirely.

This MR ensures a ::ReadmeBlob is returned instead of a ::Blob when
asking a repository for an individual blob, if the commit and path
match the readme for HEAD. This makes the cached HTML available to
consumers, including the blob viewer.

The ReadmeBlob is a simple delegator to the Blob, so should be
compatible in all cases. Adding the rendered_markdown method is the
only additional behaviour it contains.