Commits between in Gitaly only

Prior to this change, most the commits counted were done through Gitaly.
This removes the last point where this wasn't the case.

This makes the `rugged_count_commits` method obsolete, with its tests.

Closes https://gitlab.com/gitlab-org/gitaly/issues/315

lib/gitlab/git/commit.rb

@@ -116,15 +116,9 @@ module Gitlab
         #   Commit.between(repo, '29eda46b', 'master')
         #
         def between(repo, base, head)
-          Gitlab::GitalyClient.migrate(:commits_between) do |is_enabled|
-            if is_enabled
-              repo.gitaly_commit_client.between(base, head)
-            else
-              repo.rugged_commits_between(base, head).map { |c| decorate(repo, c) }
-            end
+          repo.wrapped_gitaly_errors do
+            repo.gitaly_commit_client.between(base, head)
           end
-        rescue Rugged::ReferenceError
-          []
         end
         # Returns commits collection

lib/gitlab/git/repository.rb

@@ -492,27 +492,6 @@ module Gitlab
         Ref.dereference_object(obj)
       end
-      # Return a collection of Rugged::Commits between the two revspec arguments.
-      # See http://git-scm.com/docs/git-rev-parse.html#_specifying_revisions for
-      # a detailed list of valid arguments.
-      #
-      # Gitaly note: JV: to be deprecated in favor of Commit.between
-      def rugged_commits_between(from, to)
-        walker = Rugged::Walker.new(rugged)
-        walker.sorting(Rugged::SORT_NONE | Rugged::SORT_REVERSE)
-
-        sha_from = sha_from_ref(from)
-        sha_to = sha_from_ref(to)
-
-        walker.push(sha_to)
-        walker.hide(sha_from)
-
-        commits = walker.to_a
-        walker.reset
-
-        commits
-      end
-
       # Counts the amount of commits between `from` and `to`.
       def count_commits_between(from, to, options = {})
         count_commits(from: from, to: to, **options)

spec/lib/gitlab/git/repository_spec.rb

@@ -996,46 +996,6 @@ describe Gitlab::Git::Repository, seed_helper: true do
     end
   end
-  describe "#rugged_commits_between" do
-    around do |example|
-      # TODO #rugged_commits_between will be removed, has been migrated to gitaly
-      Gitlab::GitalyClient::StorageSettings.allow_disk_access do
-        example.run
-      end
-    end
-
-    context 'two SHAs' do
-      let(:first_sha) { 'b0e52af38d7ea43cf41d8a6f2471351ac036d6c9' }
-      let(:second_sha) { '0e50ec4d3c7ce42ab74dda1d422cb2cbffe1e326' }
-
-      it 'returns the number of commits between' do
-        expect(repository.rugged_commits_between(first_sha, second_sha).count).to eq(3)
-      end
-    end
-
-    context 'SHA and master branch' do
-      let(:sha) { 'b0e52af38d7ea43cf41d8a6f2471351ac036d6c9' }
-      let(:branch) { 'master' }
-
-      it 'returns the number of commits between a sha and a branch' do
-        expect(repository.rugged_commits_between(sha, branch).count).to eq(5)
-      end
-
-      it 'returns the number of commits between a branch and a sha' do
-        expect(repository.rugged_commits_between(branch, sha).count).to eq(0) # sha is before branch
-      end
-    end
-
-    context 'two branches' do
-      let(:first_branch) { 'feature' }
-      let(:second_branch) { 'master' }
-
-      it 'returns the number of commits between' do
-        expect(repository.rugged_commits_between(first_branch, second_branch).count).to eq(17)
-      end
-    end
-  end
-
   describe '#count_commits_between' do
     subject { repository.count_commits_between('feature', 'master') }