GitLab CI Job GIT_DEPTH

2021-07-21

Failed Message

https://gitlab.com/gitlab-jh/gitlab/-/jobs/1437530056

$ bundle exec danger --fail-on-errors=true --verbose
fatal: couldn't find remote ref refs/heads/danger_base
fatal: couldn't find remote ref refs/heads/danger_head
fatal: couldn't find remote ref refs/heads/danger_base
fatal: couldn't find remote ref refs/heads/danger_head
fatal: couldn't find remote ref refs/heads/danger_base
fatal: couldn't find remote ref refs/heads/danger_head
fatal: couldn't find remote ref refs/heads/danger_base
fatal: couldn't find remote ref refs/heads/danger_head
fatal: protocol error: bad pack header
bundler: failed to load command: danger (/builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/bin/danger)
RuntimeError: Cannot find a merge base between danger_base and danger_head. If you are using shallow clone/fetch, try increasing the --depth
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/scm_source/git_repo.rb:138:in `find_merge_base'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/scm_source/git_repo.rb:22:in `diff_for_folder'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/danger_core/dangerfile.rb:274:in `setup_for_running'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/danger_core/dangerfile.rb:284:in `run'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/danger_core/executor.rb:29:in `run'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/lib/danger/commands/runner.rb:73:in `run'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/claide-1.0.3/lib/claide/command.rb:334:in `run'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/gems/danger-8.3.1/bin/danger:5:in `<top (required)>'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/bin/danger:23:in `load'
  /builds/gitlab-org-forks/gitlab/vendor/ruby/2.7.0/bin/danger:23:in `<top (required)>'

Why

GitLab and GitLab Runner perform a shallow clone by default.

Ideally, you should always use GIT_DEPTH with a small number like 10.

This instructs GitLab Runner to perform shallow clones.


Limit the number of changes fetched during clone

Under Git strategy, under Git shallow clone, enter a value. The maximum value is 1000.

To disable shallow clone and make GitLab CI/CD fetch all branches and tags each time, keep the value empty or set to 0.

In GitLab 12.0 and later, newly created projects automatically have a default git depth value of 50.

This value can be overridden by the GIT_DEPTH variable in the .gitlab-ci.yml file. 


# .gitlab-ci.yml

variables:
  RAILS_ENV: "test"
  NODE_ENV: "test"
  BUNDLE_WITHOUT: "production:development"
  BUNDLE_INSTALL_FLAGS: "--jobs=$(nproc) --retry=3 --quiet"
  NODE_OPTIONS: --max_old_space_size=3584
  GIT_DEPTH: "20"

Source Code

# app/presenters/ci/build_runner_presenter.rb

def git_depth
  if git_depth_variable
    git_depth_variable[:value]
  else
    project.ci_default_git_depth
  end.to_i
end

def git_depth_variable
  strong_memoize(:git_depth_variable) do
    variables&.find { |variable| variable[:key] == 'GIT_DEPTH' }
  end
end

# app/services/ci/register_job_service.rb

# one step of execute method
def present_build!(build)
  # We need to use the presenter here because Gitaly calls in the presenter
  # may fail, and we need to ensure the response has been generated.
  presented_build = ::Ci::BuildRunnerPresenter.new(build)
  build_json = ::API::Entities::Ci::JobRequest::Response.new(presented_build).to_json
  Result.new(build, build_json, true)
end


# lib/api/ci/runner.rb

# trigger
::Ci::RegisterJobService.new(current_runner).execute(runner_params)

Ref

https://gitlab.com/gitlab-org/gitlab/-/issues/14040

https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/28919