Merge pull request zendesk#669 from zendesk/shender/webhook_commit_co…

…mpare

Use the Github API to check if last release already contains a new commit

app/models/project.rb

@@ -66,7 +66,11 @@ def docker_repo
 
   def last_release_contains_commit?(commit)
     last_release = releases.order(:id).last
-    last_release && repository.downstream_commit?(last_release.commit, commit)
+    # status values documented here: http://stackoverflow.com/questions/23943855/github-api-to-compare-commits-response-status-is-diverged
+    last_release && %w(behind identical).include?(GITHUB.compare(github_repo, last_release.commit, commit).status)
+  rescue Octokit::Error => e
+    Airbrake.notify(e, parameters: { github_repo: github_repo, last_commit: last_release.commit, commit: commit })
+    false # Err on side of caution and cause a new release to be created.
   end
 
   def auto_release_stages

test/controllers/integrations/base_controller_test.rb

@@ -36,6 +36,7 @@
     end
 
     it 're-uses last release if commit already present' do
+      stub_github_api("repos/bar/foo/compare/#{sha}...#{sha}", { status: 'identical' })
       base_controller.expects(:head).with(:ok).twice
       base_controller.create
 

test/models/project_test.rb

@@ -21,14 +21,26 @@ def clone_repository(project)
 
     before do
       project.stubs(:repository).returns(repository)
-      repository.stubs(:downstream_commit?).with('LAST', 'NEW').returns(true)
     end
 
     it "returns true if the last release contains that commit" do
+      stub_github_api('repos/bar/foo/compare/LAST...NEW', { status: 'behind' })
       project.releases.create!(commit: "LAST", author: author)
       assert project.last_release_contains_commit?("NEW")
     end
 
+    it "returns false if last release does not contain commit" do
+      stub_github_api('repos/bar/foo/compare/LAST...NEW', { status: 'ahead' })
+      project.releases.create!(commit: "LAST", author: author)
+      refute project.last_release_contains_commit?("NEW")
+    end
+
+    it "returns true if last release has the same commit" do
+      stub_github_api('repos/bar/foo/compare/LAST...LAST', { status: 'identical' })
+      project.releases.create!(commit: "LAST", author: author)
+      assert project.last_release_contains_commit?("LAST")
+    end
+
     it "returns false if there have been no releases" do
       project.releases.destroy_all
       refute project.last_release_contains_commit?("NEW")