Backend review suggestions

Updated api attribute to issue_keys
instead of is_present as it is more verbose
Updated spec descriptions
Using params block in api
Updated use case when Jira enforcement is
not required for MR merge

ee/lib/api/entities/merge_request_jira_issue.rb

@@ -3,8 +3,8 @@
 module API
   module Entities
     class MergeRequestJiraIssue < Grape::Entity
-      expose :is_present do |merge_request|
-        Atlassian::JiraIssueKeyExtractor.has_keys?(merge_request.title, merge_request.description)
+      expose :issue_keys, if: -> (merge_request, _) { merge_request.project&.project_setting&.prevent_merge_without_jira_issue } do |merge_request|
+        Atlassian::JiraIssueKeyExtractor.new(merge_request.title, merge_request.description).issue_keys
       end
     end
   end

ee/lib/api/merge_request_jira_issue.rb

@@ -27,11 +27,14 @@ module API
         # Examples:
         #   GET /projects/:id/merge_requests/:merge_request_iid/jira_issue
         desc 'Get Jira Issue association for merge request'
+        params do
+          requires :id, type: String, desc: 'The ID of a project'
+          requires :merge_request_iid, types: [Integer, String], desc: 'The IID of a merge request'
+        end
         get 'jira_issue' do
           forbidden! unless can?(current_user, :read_merge_request, user_project)
-          not_found! unless user_project.project_setting.prevent_merge_without_jira_issue
 
-          merge_request = find_merge_request_with_access(params[:merge_request_iid])
+          merge_request = find_merge_request_with_access(declared(params)[:merge_request_iid])
 
           present_jira_issue(merge_request)
         end

ee/spec/requests/api/merge_request_jira_issue_spec.rb

@@ -12,14 +12,6 @@ RSpec.describe API::MergeRequestJiraIssue do
 
     subject { get api(url, current_user) }
 
-    shared_examples 'not found' do
-      specify do
-        subject
-
-        expect(response).to have_gitlab_http_status(:not_found)
-      end
-    end
-
     context 'when feature is available' do
       before do
         stub_licensed_features(jira_issue_association_enforcement: true)
@@ -49,7 +41,11 @@ RSpec.describe API::MergeRequestJiraIssue do
             project.create_project_setting(prevent_merge_without_jira_issue: false)
           end
 
-          it_behaves_like 'not found'
+          it 'does not include attribute issue_keys' do
+            subject
+
+            expect(json_response).not_to have_key(:issue_keys)
+          end
         end
 
         context 'when jira issue is required for merge' do
@@ -57,17 +53,17 @@ RSpec.describe API::MergeRequestJiraIssue do
             project.create_project_setting(prevent_merge_without_jira_issue: true)
           end
 
-          it 'responds with not found' do
+          it 'responds with status :ok' do
             subject
 
             expect(response).to have_gitlab_http_status(:ok)
           end
 
           context 'when Jira issue is not provided in MR title/description' do
-            it 'responds with not found' do
+            it 'responds with empty issue key' do
               subject
 
-              expect(json_response["is_present"]).to eq(false)
+              expect(json_response["issue_keys"]).to be_empty
             end
           end
 
@@ -76,22 +72,22 @@ RSpec.describe API::MergeRequestJiraIssue do
               merge_request.update!(title: 'Fix PRODUCT-1234')
             end
 
-            it 'responds with not found' do
+            it 'responds with the issue key in MR title' do
               subject
 
-              expect(json_response["is_present"]).to eq(true)
+              expect(json_response["issue_keys"]).to eq(["PRODUCT-1234"])
             end
           end
 
           context 'when Jira issue is provided in MR description' do
             before do
-              merge_request.update!(description: 'Jira issue associated: PRODUCT-1234')
+              merge_request.update!(description: 'Jira issue associated: FEATURE-1234')
             end
 
-            it 'responds with not found' do
+            it 'responds with the issue key in MR description' do
               subject
 
-              expect(json_response["is_present"]).to eq(true)
+              expect(json_response["issue_keys"]).to eq(["FEATURE-1234"])
             end
           end
         end
@@ -103,6 +99,14 @@ RSpec.describe API::MergeRequestJiraIssue do
 
       let(:current_user) { user }
 
+      shared_examples 'not found' do
+        specify do
+          subject
+
+          expect(response).to have_gitlab_http_status(:not_found)
+        end
+      end
+
       where(:licensed, :feature_flag) do
         false | true
         true  | false