Raw changes calculation is Gitaly only now

Closes https://gitlab.com/gitlab-org/gitaly/issues/1138

lib/gitlab/git/repository.rb

@@ -529,30 +529,15 @@ module Gitlab
       def raw_changes_between(old_rev, new_rev)
         @raw_changes_between ||= {}
 
-        @raw_changes_between[[old_rev, new_rev]] ||= begin
+        @raw_changes_between[[old_rev, new_rev]] ||=
+          begin
             return [] if new_rev.blank? || new_rev == Gitlab::Git::BLANK_SHA
 
-          gitaly_migrate(:raw_changes_between) do |is_enabled|
-            if is_enabled
+            wrapped_gitaly_errors do
               gitaly_repository_client.raw_changes_between(old_rev, new_rev)
                 .each_with_object([]) do |msg, arr|
                 msg.raw_changes.each { |change| arr << ::Gitlab::Git::RawDiffChange.new(change) }
               end
-            else
-              result = []
-
-              circuit_breaker.perform do
-                Open3.pipeline_r(git_diff_cmd(old_rev, new_rev), format_git_cat_file_script, git_cat_file_cmd) do |last_stdout, wait_threads|
-                  last_stdout.each_line { |line| result << ::Gitlab::Git::RawDiffChange.new(line.chomp!) }
-
-                  if wait_threads.any? { |waiter| !waiter.value&.success? }
-                    raise ::Gitlab::Git::Repository::GitError, "Unabled to obtain changes between #{old_rev} and #{new_rev}"
-                  end
-                end
-              end
-
-              result
-            end
             end
           end
       rescue ArgumentError => e

spec/lib/gitlab/git/repository_spec.rb

@@ -1043,7 +1043,6 @@ describe Gitlab::Git::Repository, seed_helper: true do
   end
 
   describe '#raw_changes_between' do
-    shared_examples 'raw changes' do
     let(:old_rev) { }
     let(:new_rev) { }
     let(:changes) { repository.raw_changes_between(old_rev, new_rev) }
@@ -1081,15 +1080,6 @@ describe Gitlab::Git::Repository, seed_helper: true do
     end
   end
 
-    context 'when gitaly is enabled' do
-      it_behaves_like 'raw changes'
-    end
-
-    context 'when gitaly is disabled', :disable_gitaly do
-      it_behaves_like 'raw changes'
-    end
-  end
-
   describe '#merge_base' do
     shared_examples '#merge_base' do
       where(:from, :to, :result) do