Load commit in batches for pipelines#index

Uses `list_commits_by_oid` on the CommitService, to request the needed
commits for pipelines. These commits are needed to display the user that
created the commit and the commit title.

This includes fixes for tests failing that depended on the commit
being `nil`. However, now these are batch loaded, this doesn't happen
anymore and the commits are an instance of BatchLoader.

1 files changed, 17 insertions, 3 deletions

diff --git a/app/models/commit.rb b/app/models/commit.rb
index 13c31111134..2be07ca7d3c 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -86,6 +86,20 @@ class Commit
     def valid_hash?(key)
       !!(/\A#{COMMIT_SHA_PATTERN}\z/ =~ key)
     end
+
+    def lazy(project, oid)
+      BatchLoader.for({ project: project, oid: oid }).batch do |items, loader|
+        items_by_project = items.group_by { |i| i[:project] }
+
+        items_by_project.each do |project, commit_ids|
+          oids = commit_ids.map { |i| i[:oid] }
+
+          project.repository.commits_by(oids: oids).each do |commit|
+            loader.call({ project: commit.project, oid: commit.id }, commit) if commit
+          end
+        end
+      end
+    end
   end
 
   attr_accessor :raw
@@ -103,7 +117,7 @@ class Commit
   end
 
   def ==(other)
-    (self.class === other) && (raw == other.raw)
+    other.is_a?(self.class) && raw == other.raw
   end
 
   def self.reference_prefix
@@ -224,8 +238,8 @@ class Commit
     notes.includes(:author)
   end
 
-  def method_missing(m, *args, &block)
-    @raw.__send__(m, *args, &block) # rubocop:disable GitlabSecurity/PublicSend
+  def method_missing(method, *args, &block)
+    @raw.__send__(method, *args, &block) # rubocop:disable GitlabSecurity/PublicSend
   end
 
   def respond_to_missing?(method, include_private = false)