Fix EmailsOnPush comparison link to include first commit.

app/mailers/emails/projects.rb

@@ -31,8 +31,8 @@ module Emails
       if @commits.length > 1
         @target_url = namespace_project_compare_url(@project.namespace,
                                                     @project,
-                                                    from: @commits.first,
-                                                    to: @commits.last)
+                                                    from: Commit.new(@compare.base),
+                                                    to:   Commit.new(@compare.head))
         @subject << "Deleted " if @reverse_compare
         @subject << "#{@commits.length} commits: #{@commits.first.title}"
       else

spec/mailers/notify_spec.rb

@@ -568,7 +568,7 @@ describe Notify do
     let(:user) { create(:user) }
     let(:compare) { Gitlab::Git::Compare.new(project.repository.raw_repository, sample_image_commit.id, sample_commit.id) }
     let(:commits) { Commit.decorate(compare.commits) }
-    let(:diff_path) { namespace_project_compare_path(project.namespace, project, from: commits.first, to: commits.last) }
+    let(:diff_path) { namespace_project_compare_path(project.namespace, project, from: Commit.new(compare.base), to: Commit.new(compare.head)) }
     let(:send_from_committer_email) { false }
 
     subject { Notify.repository_push_email(project.id, 'devs@company.name', user.id, 'master', compare, false, send_from_committer_email) }