Fix: gracefully ignore unverified commits when choosing deploy assignee

Author: joeyAghion

app/services/deploy_service.rb

@@ -99,7 +99,7 @@ def choose_assignee(pull_request)
     github_client
       .pull_request_commits(github_repo, pull_request.number)
       .flat_map { |c| [c.author, c.committer] }
-      .reject { |c| c.type == 'Bot' || c.login == 'web-flow' || c.login == 'artsyit' || c.login[/\bbot\b/] }
+      .reject { |c| c.nil? || c.type == 'Bot' || c.login == 'web-flow' || c.login == 'artsyit' || c.login[/\bbot\b/] }
       .group_by(&:login).map { |k, v| [v.size, k] }.sort.reverse.map(&:last)
       .detect { |l| github_client.check_assignee(github_repo, l) }
   end

spec/features/deploy_spec.rb

@@ -79,6 +79,21 @@
     DeployService.new(strategy).start
   end
 
+  it 'handles unsigned commits' do
+    expect_any_instance_of(Octokit::Client).to receive(:create_pull_request)
+      .with('artsy/candela', 'release', 'staging', anything, anything)
+      .and_return(github_pull_request)
+    allow_any_instance_of(Octokit::Client).to receive(:pull_request_commits)
+      .with('artsy/candela', 42)
+      .and_return([
+                    double(author: nil, committer: renovate),
+                    double(author: jane, committer: web_flow)
+                  ])
+    expect_any_instance_of(Octokit::Client).to receive(:check_assignee).and_return(true)
+    expect_any_instance_of(Octokit::Client).to receive(:add_assignees).with('artsy/candela', 42, 'jane')
+    DeployService.new(strategy).start
+  end
+
   it 'adds assignees to existing deploy PRs when unassigned' do
     expect_any_instance_of(Octokit::Client).to receive(:create_pull_request)
       .with('artsy/candela', 'release', 'staging', anything, anything)