Simplify issue types fetching logic

Jira API exposes `issueTypes` on Project details API which means we can
simplify the logic used to fetch issue types available for any given
project.

ee/app/models/ee/integrations/jira.rb

@@ -87,71 +87,22 @@ module EE
         end
       end
 
-      # Returns list of Issue Type Scheme IDs in selected JIRA Project
-      #
-      # @return [Array] the array of IDs
-      def project_issuetype_scheme_ids
-        raise NotImplementedError unless data_fields.deployment_cloud?
-
-        query_url = Addressable::URI.join("#{client.options[:rest_base_path]}/", 'issuetypescheme/', 'project')
-        query_url.query_values = { 'projectId' => jira_project_id }
-
-        client
-          .get(query_url.to_s)
-          .fetch('values', [])
-          .map { |schemes| schemes.dig('issueTypeScheme', 'id') }
-      end
-
-      # Returns list of Issue Type IDs available in active Issue Type Scheme in selected JIRA Project
-      #
-      # @return [Array] the array of IDs
-      def project_issuetype_ids
-        strong_memoize(:project_issuetype_ids) do
-          if data_fields.deployment_server?
-            project_issuetype_ids_from_project_details
-          elsif data_fields.deployment_cloud?
-            # According to https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-issue-type-schemes/#api-rest-api-3-issuetypescheme-project-get
-            # only classic projects has issue type schemes
-            next project_issuetype_ids_from_project_details if jira_project.style == "next-gen"
-
-            project_issuetype_ids_from_issuetypescheme_mappings
-          else
-            raise NotImplementedError
-          end
-        end
-      end
-
-      def project_issuetype_ids_from_issuetypescheme_mappings
-        query_url = Addressable::URI.join("#{client.options[:rest_base_path]}/", 'issuetypescheme/', 'mapping')
-        query_url.query_values = { 'issueTypeSchemeId' => project_issuetype_scheme_ids }
-
-        client
-          .get(query_url.to_s)
-          .fetch('values', [])
-          .map { |schemes| schemes['issueTypeId'] }
-      end
-
-      def project_issuetype_ids_from_project_details
-        query_url = Addressable::URI.join("#{client.options[:rest_base_path]}/", 'project/', project_key)
-
-        client
-          .get(query_url.to_s)
-          .fetch('issueTypes', [])
-          .map { |issue_type| issue_type['id'] }
-      end
-
       # Returns list of available Issue types in selected JIRA Project
       #
       # @return [Array] the array of objects with JIRA Issuetype ID, Name and Description
       def issue_types
         return [] if jira_project.blank?
 
-        client
-          .Issuetype
-          .all
-          .select { |issue_type| issue_type.id.in?(project_issuetype_ids) }
+        jira_project
+          .issuetypes
           .reject { |issue_type| issue_type.subtask }
-          .map { |issue_type| { id: issue_type.id, name: issue_type.name, description: issue_type.description } }
+          .map do |issue_type|
+          {
+            id: issue_type.id,
+            name: issue_type.name,
+            description: issue_type.description
+          }
+        end
       end
     end
   end

ee/spec/models/ee/integrations/jira_spec.rb

@@ -111,16 +111,10 @@ RSpec.describe Integrations::Jira do
             }
           end
 
-          let(:classic_issuetypes) do
+          context 'when JIRA project style is classic' do
+            let(:jira_project_style) { 'classic' }
+            let(:project_issue_types) do
               [
-              {
-                id: '10004',
-                description: 'A new feature of the product, which has yet to be developed.',
-                name: 'New Feature',
-                untranslatedName: 'New Feature',
-                subtask: false,
-                avatarId: 10311
-              },
                 {
                   id: '10001',
                   description: 'Jira Bug',
@@ -140,7 +134,22 @@ RSpec.describe Integrations::Jira do
               ]
             end
 
-          let(:nextgen_issuetypes) do
+            let(:expected_data) do
+              {
+                issuetypes: project_issue_types.select { |it| !it[:subtask] }.map { |it| it.slice(*%i[id name description]) }
+              }
+            end
+
+            before do
+              WebMock.stub_request(:get, %r{api/2/project/GL}).with(basic_auth: %w(gitlab_jira_username gitlab_jira_password)).to_return(body: project_info_result.to_json )
+            end
+
+            it { is_expected.to eq(success: true, result: { jira: true }, data: { issuetypes: [{ id: '10001', name: 'Bug', description: 'Jira Bug' }] }) }
+          end
+
+          context 'when JIRA project style is next-gen' do
+            let(:jira_project_style) { 'next-gen' }
+            let(:project_issue_types) do
               [
                 {
                   id: '2137',
@@ -169,67 +178,14 @@ RSpec.describe Integrations::Jira do
               ]
             end
 
-          let(:issue_types_response) { classic_issuetypes + nextgen_issuetypes }
-
-          context 'when JIRA project style is classic' do
-            let(:jira_project_style) { 'classic' }
-            let(:project_issue_types) { classic_issuetypes }
-
-            let(:issue_type_scheme_response) do
-              {
-                values: [
-                  {
-                    issueTypeScheme: {
-                      id: '10126',
-                      name: 'GV: Software Development Issue Type Scheme',
-                      defaultIssueTypeId: '10001'
-                    },
-                    projectIds: [
-                      '10000'
-                    ]
-                  }
-                ]
-              }
-            end
-
-            let(:issue_type_mapping_response) do
-              {
-                values: [
-                  {
-                    issueTypeSchemeId: '10126',
-                    issueTypeId: '10003'
-                  },
-                  {
-                    issueTypeSchemeId: '10126',
-                    issueTypeId: '10001'
-                  }
-                ]
-              }
-            end
-
-            before do
-              WebMock.stub_request(:get, %r{api/2/project/GL}).with(basic_auth: %w(gitlab_jira_username gitlab_jira_password)).to_return(body: project_info_result.to_json )
-              WebMock.stub_request(:get, %r{api/2/issuetype\z}).to_return(body: issue_types_response.to_json, headers: headers)
-              WebMock.stub_request(:get, %r{api/2/issuetypescheme/project\?projectId\=10000\z}).to_return(body: issue_type_scheme_response.to_json, headers: headers)
-              WebMock.stub_request(:get, %r{api/2/issuetypescheme/mapping\?issueTypeSchemeId\=10126\z}).to_return(body: issue_type_mapping_response.to_json, headers: headers)
-            end
-
-            it { is_expected.to eq(success: true, result: { jira: true }, data: { issuetypes: [{ id: '10001', name: 'Bug', description: 'Jira Bug' }] }) }
-          end
-
-          context 'when JIRA project style is next-gen' do
-            let(:jira_project_style) { 'next-gen' }
-            let(:project_issue_types) { nextgen_issuetypes }
-
             let(:expected_data) do
               {
-                issuetypes: nextgen_issuetypes.select { |issue_type| !issue_type[:subtask] }.map { |issue_type| issue_type.slice(*%i[id name description]) }
+                issuetypes: project_issue_types.select { |it| !it[:subtask] }.map { |it| it.slice(*%i[id name description]) }
               }
             end
 
             before do
               WebMock.stub_request(:get, %r{api/2/project/GL}).with(basic_auth: %w(gitlab_jira_username gitlab_jira_password)).to_return(body: project_info_result.to_json, headers: headers)
-              WebMock.stub_request(:get, %r{api/2/issuetype\z}).to_return(body: issue_types_response.to_json, headers: headers)
             end
 
             it { is_expected.to eq(success: true, result: { jira: true }, data: expected_data) }