Merge branch 'feature/migrate-merge-base-to-gitaly' into 'master'

Migrate Gitlab::Git::Repository#merge_base_commit to Gitaly

Closes gitaly#808

See merge request gitlab-org/gitlab-ce!15770

3 files changed, 19 insertions, 2 deletions

diff --git a/lib/gitlab/git/operation_service.rb b/lib/gitlab/git/operation_service.rb
index 7e8fe173056..ef5bdbaf819 100644
--- a/lib/gitlab/git/operation_service.rb
+++ b/lib/gitlab/git/operation_service.rb
@@ -126,7 +126,7 @@ module Gitlab
 
         oldrev = branch.target
 
-        if oldrev == repository.rugged.merge_base(newrev, branch.target)
+        if oldrev == repository.merge_base(newrev, branch.target)
           oldrev
         else
           raise Gitlab::Git::CommitError.new('Branch diverged')
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index 0e0a1987c7d..369bb16f719 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -517,8 +517,15 @@ module Gitlab
 
       # Returns the SHA of the most recent common ancestor of +from+ and +to+
       def merge_base_commit(from, to)
-        rugged.merge_base(from, to)
+        gitaly_migrate(:merge_base) do |is_enabled|
+          if is_enabled
+            gitaly_repository_client.find_merge_base(from, to)
+          else
+            rugged.merge_base(from, to)
+          end
+        end
       end
+      alias_method :merge_base, :merge_base_commit
 
       # Gitaly note: JV: check gitlab-ee before removing this method.
       def rugged_is_ancestor?(ancestor_id, descendant_id)
diff --git a/lib/gitlab/gitaly_client/repository_service.rb b/lib/gitlab/gitaly_client/repository_service.rb
index a477d618f63..c1f95396878 100644
--- a/lib/gitlab/gitaly_client/repository_service.rb
+++ b/lib/gitlab/gitaly_client/repository_service.rb
@@ -69,6 +69,16 @@ module Gitlab
         response.value
       end
 
+      def find_merge_base(*revisions)
+        request = Gitaly::FindMergeBaseRequest.new(
+          repository: @gitaly_repo,
+          revisions: revisions.map { |r| GitalyClient.encode(r) }
+        )
+
+        response = GitalyClient.call(@storage, :repository_service, :find_merge_base, request)
+        response.base.presence
+      end
+
       def fetch_source_branch(source_repository, source_branch, local_ref)
         request = Gitaly::FetchSourceBranchRequest.new(
           repository: @gitaly_repo,