Improve Add/Remove MR Labels API Feature

Add add_labels and remove_labels options

app/services/issuable_base_service.rb

@@ -22,7 +22,9 @@ class IssuableBaseService < BaseService
       params.delete(:milestone_id)
       params.delete(:labels)
       params.delete(:add_label_ids)
+      params.delete(:add_labels)
       params.delete(:remove_label_ids)
+      params.delete(:remove_labels)
       params.delete(:label_ids)
       params.delete(:assignee_ids)
       params.delete(:assignee_id)

changelogs/unreleased/improve_add_remove_labels_api.yml

+---
+title: Add ability to add or remove MR labels via API
+merge_request: 31522
+author: Lee Tickett
+type: changed

doc/api/merge_requests.md

@@ -1130,6 +1130,8 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 | `assignee_ids`             | integer array | no | The ID of the user(s) to assign the MR to. Set to `0` or provide an empty value to unassign all assignees.  |
 | `milestone_id`             | integer | no       | The global ID of a milestone to assign the merge request to. Set to `0` or provide an empty value to unassign a milestone.|
 | `labels`                   | string  | no       | Comma-separated label names for a merge request. Set to an empty string to unassign all labels.                    |
+| `add_labels`               | string  | no       | Comma-separated label names to add to a merge request.                          |
+| `remove_labels`            | string  | no       | Comma-separated label names to remove from a merge request.                     |
 | `description`              | string  | no       | Description of MR. Limited to 1,048,576 characters. |
 | `state_event`              | string  | no       | New state (close/reopen)                                                        |
 | `remove_source_branch`     | boolean | no       | Flag indicating if a merge request should remove the source branch when merging |

lib/api/merge_requests.rb

@@ -26,6 +26,8 @@ module API
         assignee_ids
         description
         labels
+        add_labels
+        remove_labels
         milestone_id
         remove_source_branch
         state_event
@@ -180,6 +182,8 @@ module API
           optional :assignee_ids, type: Array[Integer], desc: 'The array of user IDs to assign issue'
           optional :milestone_id, type: Integer, desc: 'The ID of a milestone to assign the merge request'
           optional :labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
+          optional :add_labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
+          optional :remove_labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
           optional :remove_source_branch, type: Boolean, desc: 'Remove source branch when merging'
           optional :allow_collaboration, type: Boolean, desc: 'Allow commits from members who can merge to the target branch'
           optional :allow_maintainer_to_push, type: Boolean, as: :allow_collaboration, desc: '[deprecated] See allow_collaboration'

spec/requests/api/merge_requests_spec.rb

@@ -2308,6 +2308,33 @@ describe API::MergeRequests do
       end
     end
 
+    context 'with labels' do
+      include_context 'with labels'
+
+      let(:api_base) { api("/projects/#{project.id}/merge_requests/#{merge_request.iid}", user) }
+
+      it 'when adding labels, keeps existing labels and adds new' do
+        put api_base, params: { add_labels: '1, 2' }
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response['labels']).to contain_exactly(label.title, label2.title, '1', '2')
+      end
+
+      it 'when removing labels, only removes those specified' do
+        put api_base, params: { remove_labels: "#{label.title}" }
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response['labels']).to eq([label2.title])
+      end
+
+      it 'when removing all labels, keeps no labels' do
+        put api_base, params: { remove_labels: "#{label.title}, #{label2.title}" }
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response['labels']).to be_empty
+      end
+    end
+
     it 'does not update state when title is empty' do
       put api("/projects/#{project.id}/merge_requests/#{merge_request.iid}", user), params: { state_event: 'close', title: nil }