Fix label serialisation in issue and note hooks

We were not calling hook_attrs on the labels correctly. Specs were
passing because the issues under test did not have any labels!

changelogs/unreleased/fix-labels-in-hooks.yml

+---
+title: Fix label serialization in issue and note hooks
+merge_request: 29850
+author:
+type: fixed

lib/gitlab/data_builder/note.rb

@@ -44,7 +44,7 @@ module Gitlab
           data[:commit] = build_data_for_commit(project, user, note)
         elsif note.for_issue?
           data[:issue] = note.noteable.hook_attrs
-          data[:issue][:labels] = note.noteable.labels(&:hook_attrs)
+          data[:issue][:labels] = note.noteable.labels.map(&:hook_attrs)
         elsif note.for_merge_request?
           data[:merge_request] = note.noteable.hook_attrs
         elsif note.for_snippet?

lib/gitlab/hook_data/issue_builder.rb

@@ -45,7 +45,7 @@ module Gitlab
             human_time_estimate: issue.human_time_estimate,
             assignee_ids: issue.assignee_ids,
             assignee_id: issue.assignee_ids.first, # This key is deprecated
-            labels: issue.labels
+            labels: issue.labels.map(&:hook_attrs)
         }
 
         issue.attributes.with_indifferent_access.slice(*self.class.safe_hook_attributes)

spec/lib/gitlab/data_builder/note_spec.rb

@@ -38,9 +38,11 @@ describe Gitlab::DataBuilder::Note do
   end
 
   describe 'When asking for a note on issue' do
+    let(:label) { create(:label, project: project) }
+
     let(:issue) do
-      create(:issue, created_at: fixed_time, updated_at: fixed_time,
-                     project: project)
+      create(:labeled_issue, created_at: fixed_time, updated_at: fixed_time,
+             project: project, labels: [label])
     end
 
     let(:note) do
@@ -48,13 +50,16 @@ describe Gitlab::DataBuilder::Note do
     end
 
     it 'returns the note and issue-specific data' do
+      without_timestamps = lambda { |label| label.except('created_at', 'updated_at') }
+      hook_attrs = issue.reload.hook_attrs
+
       expect(data).to have_key(:issue)
-      expect(data[:issue].except('updated_at'))
-        .to eq(issue.reload.hook_attrs.except('updated_at'))
+      expect(data[:issue].except('updated_at', 'labels'))
+        .to eq(hook_attrs.except('updated_at', 'labels'))
       expect(data[:issue]['updated_at'])
-        .to be >= issue.hook_attrs['updated_at']
-      expect(data[:issue]['labels'])
-        .to eq(issue.hook_attrs['labels'])
+        .to be >= hook_attrs['updated_at']
+      expect(data[:issue]['labels'].map(&without_timestamps))
+        .to eq(hook_attrs['labels'].map(&without_timestamps))
     end
 
     context 'with confidential issue' do

spec/lib/gitlab/hook_data/issue_builder_spec.rb

 require 'spec_helper'
 
 describe Gitlab::HookData::IssueBuilder do
-  set(:issue) { create(:issue) }
+  set(:label) { create(:label) }
+  set(:issue) { create(:labeled_issue, labels: [label], project: label.project) }
   let(:builder) { described_class.new(issue) }
 
   describe '#build' do
@@ -39,6 +40,7 @@ describe Gitlab::HookData::IssueBuilder do
       expect(data).to include(:human_time_estimate)
       expect(data).to include(:human_total_time_spent)
       expect(data).to include(:assignee_ids)
+      expect(data).to include('labels' => [label.hook_attrs])
     end
 
     context 'when the issue has an image in the description' do