Allow resetting issue labels

Add the ability to set an array of lables to an issue, without having
to remove/add labels to do that.

Changelog :added

app/graphql/mutations/issues/update.rb

@@ -23,6 +23,10 @@ module Mutations
                required: false,
                description: 'The IDs of labels to be removed from the issue.'
 
+      argument :label_ids, [GraphQL::Types::ID],
+               required: false,
+               description: 'The IDs of labels to be set. Replaces existing issue labels.'
+
       argument :state_event, Types::IssueStateEventEnum,
                description: 'Close or reopen an issue.',
                required: false
@@ -31,6 +35,8 @@ module Mutations
         issue = authorized_find!(project_path: project_path, iid: iid)
         project = issue.project
 
+        args = parse_arguments(args)
+
         spam_params = ::Spam::SpamParams.new_from_request(request: context[:request])
         ::Issues::UpdateService.new(project: project, current_user: current_user, params: args, spam_params: spam_params).execute(issue)
 
@@ -39,6 +45,32 @@ module Mutations
           errors: errors_on_object(issue)
         }
       end
+
+      def ready?(label_ids: [], add_label_ids: [], remove_label_ids: [], **args)
+        if label_ids.any? && (add_label_ids.any? || remove_label_ids.any?)
+          raise Gitlab::Graphql::Errors::ArgumentError, 'labelIds is mutually exclusive with any of addLabelIds or removeLabelIds'
+        end
+
+        super
+      end
+
+      private
+
+      def parse_arguments(args)
+        args[:add_label_ids] = parse_label_ids(args[:add_label_ids])
+        args[:remove_label_ids] = parse_label_ids(args[:remove_label_ids])
+        args[:label_ids] = parse_label_ids(args[:label_ids])
+
+        args
+      end
+
+      def parse_label_ids(ids)
+        ids&.map do |gid|
+          GitlabSchema.parse_gid(gid, expected_type: ::Label).model_id
+        rescue Gitlab::Graphql::Errors::ArgumentError
+          gid
+        end
+      end
     end
   end
 end

doc/api/graphql/reference/index.md

@@ -4176,6 +4176,7 @@ Input type: `UpdateIssueInput`
 | <a id="mutationupdateissueepicid"></a>`epicId` | [`EpicID`](#epicid) | The ID of the parent epic. NULL when removing the association. |
 | <a id="mutationupdateissuehealthstatus"></a>`healthStatus` | [`HealthStatus`](#healthstatus) | The desired health status. |
 | <a id="mutationupdateissueiid"></a>`iid` | [`String!`](#string) | The IID of the issue to mutate. |
+| <a id="mutationupdateissuelabelids"></a>`labelIds` | [`[ID!]`](#id) | The IDs of labels to be set. Replaces existing issue labels. |
 | <a id="mutationupdateissuelocked"></a>`locked` | [`Boolean`](#boolean) | Indicates discussion is locked on the issue. |
 | <a id="mutationupdateissuemilestoneid"></a>`milestoneId` | [`ID`](#id) | The ID of the milestone to assign to the issue. On update milestone will be removed if set to null. |
 | <a id="mutationupdateissueprojectpath"></a>`projectPath` | [`ID!`](#id) | The project the issue to mutate is in. |

spec/graphql/mutations/issues/update_spec.rb

@@ -131,6 +131,28 @@ RSpec.describe Mutations::Issues::Update do
 
           expect(issue.reload.labels).to match_array([project_label, label_2])
         end
+
+        context 'when setting labels with label_ids' do
+          it 'replaces existing labels with provided ones' do
+            expect(issue.reload.labels).to match_array([project_label])
+
+            mutation_params[:label_ids] = [label_1.id, label_2.id]
+
+            subject
+
+            expect(issue.reload.labels).to match_array([label_1, label_2])
+          end
+
+          it 'raises error when label_ids is combined with remove_label_ids' do
+            expect { mutation.ready?(label_ids: [label_1.id, label_2.id], remove_label_ids: [label_1.id]) }
+              .to raise_error(Gitlab::Graphql::Errors::ArgumentError, 'labelIds is mutually exclusive with any of addLabelIds or removeLabelIds')
+          end
+
+          it 'raises error when label_ids is combined with add_label_ids' do
+            expect { mutation.ready?(label_ids: [label_1.id, label_2.id], add_label_ids: [label_2.id]) }
+              .to raise_error(Gitlab::Graphql::Errors::ArgumentError, 'labelIds is mutually exclusive with any of addLabelIds or removeLabelIds')
+          end
+        end
       end
 
       context 'when changing type' do

spec/requests/api/graphql/mutations/issues/update_spec.rb

@@ -8,6 +8,8 @@ RSpec.describe 'Update of an existing issue' do
   let_it_be(:current_user) { create(:user) }
   let_it_be(:project) { create(:project, :public) }
   let_it_be(:issue) { create(:issue, project: project) }
+  let_it_be(:label1) { create(:label, project: project) }
+  let_it_be(:label2) { create(:label, project: project) }
 
   let(:input) do
     {
@@ -20,7 +22,9 @@ RSpec.describe 'Update of an existing issue' do
     }
   end
 
-  let(:mutation) { graphql_mutation(:update_issue, input.merge(project_path: project.full_path, locked: true)) }
+  let(:extra_params) { { project_path: project.full_path, locked: true } }
+  let(:input_params) { input.merge(extra_params) }
+  let(:mutation) { graphql_mutation(:update_issue, input_params) }
   let(:mutation_response) { graphql_mutation_response(:update_issue) }
 
   context 'the user is not allowed to update issue' do
@@ -39,5 +43,82 @@ RSpec.describe 'Update of an existing issue' do
       expect(mutation_response['issue']).to include(input)
       expect(mutation_response['issue']).to include('discussionLocked' => true)
     end
+
+    context 'setting labels' do
+      let(:mutation) do
+        graphql_mutation(:update_issue, input_params) do
+          <<~QL
+              issue {
+                 labels {
+                   nodes {
+                     id
+                   }
+                 }
+              }
+              errors
+          QL
+        end
+      end
+
+      context 'reset labels' do
+        let(:input_params) { input.merge(extra_params).merge({ labelIds: [label1.id, label2.id] }) }
+
+        it 'resets labels' do
+          post_graphql_mutation(mutation, current_user: current_user)
+
+          expect(response).to have_gitlab_http_status(:success)
+          expect(json_response['errors']).to be_nil
+          expect(mutation_response['issue']['labels']).to include({ "nodes" => [{ "id" => label1.to_global_id.to_s }, { "id" => label2.to_global_id.to_s }] })
+        end
+
+        context 'reset labels and add labels' do
+          let(:input_params) { input.merge(extra_params).merge({ labelIds: [label1.id], addLabelIds: [label2.id] }) }
+
+          it 'returns error for mutually exclusive arguments' do
+            post_graphql_mutation(mutation, current_user: current_user)
+
+            expect(response).to have_gitlab_http_status(:success)
+            expect(json_response['errors'].first['message']).to eq('labelIds is mutually exclusive with any of addLabelIds or removeLabelIds')
+            expect(mutation_response).to be_nil
+          end
+        end
+
+        context 'reset labels and remove labels' do
+          let(:input_params) { input.merge(extra_params).merge({ labelIds: [label1.id], removeLabelIds: [label2.id] }) }
+
+          it 'returns error for mutually exclusive arguments' do
+            post_graphql_mutation(mutation, current_user: current_user)
+
+            expect(response).to have_gitlab_http_status(:success)
+            expect(json_response['errors'].first['message']).to eq('labelIds is mutually exclusive with any of addLabelIds or removeLabelIds')
+            expect(mutation_response).to be_nil
+          end
+        end
+
+        context 'with global label ids' do
+          let(:input_params) { input.merge(extra_params).merge({ labelIds: [label1.to_global_id.to_s, label2.to_global_id.to_s] }) }
+
+          it 'resets labels' do
+            post_graphql_mutation(mutation, current_user: current_user)
+
+            expect(response).to have_gitlab_http_status(:success)
+            expect(json_response['errors']).to be_nil
+            expect(mutation_response['issue']['labels']).to include({ "nodes" => [{ "id" => label1.to_global_id.to_s }, { "id" => label2.to_global_id.to_s }] })
+          end
+        end
+      end
+
+      context 'add and remove labels' do
+        let(:input_params) { input.merge(extra_params).merge({ addLabelIds: [label1.id], removeLabelIds: [label2.id] }) }
+
+        it 'returns error for mutually exclusive arguments' do
+          post_graphql_mutation(mutation, current_user: current_user)
+
+          expect(response).to have_gitlab_http_status(:success)
+          expect(json_response['errors']).to be_nil
+          expect(mutation_response['issue']['labels']).to include({ "nodes" => [{ "id" => label1.to_global_id.to_s }] })
+        end
+      end
+    end
   end
 end