gitlab-org--gitlab-foss/app/finders/merge_requests_finder.rb

# Finders::MergeRequest class
#
# Used to filter MergeRequests collections by set of params
#
# Arguments:
#   current_user - which user use
#   params:
#     scope: 'created-by-me' or 'assigned-to-me' or 'all'
#     state: 'open', 'closed', 'merged', or 'all'
#     group_id: integer
#     project_id: integer
#     milestone_title: string
#     author_id: integer
#     assignee_id: integer
#     search: string
#     label_name: string
#     sort: string
#     non_archived: boolean
#     my_reaction_emoji: string
#     source_branch: string
#     target_branch: string
#     created_after: datetime
#     created_before: datetime
#     updated_after: datetime
#     updated_before: datetime
#
class MergeRequestsFinder < IssuableFinder
  def klass
    MergeRequest
  end

  def filter_items(_items)
    items = by_source_branch(super)

    by_target_branch(items)
  end

  private

  def source_branch
    @source_branch ||= params[:source_branch].presence
  end

  def by_source_branch(items)
    return items unless source_branch

    items.where(source_branch: source_branch)
  end

  def target_branch
    @target_branch ||= params[:target_branch].presence
  end

  def by_target_branch(items)
    return items unless target_branch

    items.where(target_branch: target_branch)
  end

  def item_project_ids(items)
    items&.reorder(nil)&.select(:target_project_id)
  end
end