Resolve "Allow reviewers to be updated via API"

changelogs/unreleased/292714-allow-reviewers-to-be-updated-via-api.yml

+---
+title: Allow reviewers to be updated via MergeRequest API
+merge_request: 51186
+author:
+type: added

doc/api/merge_requests.md

@@ -15,6 +15,7 @@ type: reference, api
 > - `reference` was [deprecated](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/20354) in GitLab 12.10 in favour of `references`.
 > - `with_merge_status_recheck` was [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/31890) in GitLab 13.0.
 > - `reviewer_username` and `reviewer_id` were [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/49341) in GitLab 13.8.
+> - `reviewer_ids` was [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/51186) in GitLab 13.8.
 
 Every API call to merge requests must be authenticated.
 
@@ -1060,6 +1061,8 @@ POST /projects/:id/merge_requests
 | `title`                    | string  | yes      | Title of MR.                                                                     |
 | `assignee_id`              | integer | no       | Assignee user ID.                                                                |
 | `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.  |
+| `assignee_ids`             | integer array | no | The ID of the user(s) to assign the MR to. If set to `0` or left empty, there will be no assignees added.  |
+| `reviewer_ids`             | integer array | no | The ID of the user(s) added as a reviewer to the MR. If set to `0` or left empty, there will be no reviewers added.  |
 | `description`              | string  | no       | Description of MR. Limited to 1,048,576 characters. |
 | `target_project_id`        | integer | no       | The target project (numeric ID).                                                 |
 | `labels`                   | string  | no       | Labels for MR as a comma-separated list.                                         |
@@ -1208,6 +1211,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 | `title`                    | string  | no       | Title of MR.                                                                     |
 | `assignee_id`              | integer | no       | The ID of the user to assign the merge request to. Set to `0` or provide an empty value to unassign all assignees.  |
 | `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.  |
+| `reviewer_ids`             | integer array | no | The ID of the user(s) set as a reviewer to the MR. Set the value to `0` or provide an empty value to unset all reviewers.  |
 | `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.                          |

lib/api/merge_requests.rb

@@ -26,6 +26,7 @@ module API
       %i[
         assignee_id
         assignee_ids
+        reviewer_ids
         description
         labels
         add_labels
@@ -160,7 +161,8 @@ module API
       helpers do
         params :optional_params do
           optional :assignee_id, type: Integer, desc: 'The ID of a user to assign the merge request'
-          optional :assignee_ids, type: Array[Integer], coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce, desc: 'The array of user IDs to assign issue'
+          optional :assignee_ids, type: Array[Integer], coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce, desc: 'Comma-separated list of assignee ids'
+          optional :reviewer_ids, type: Array[Integer], coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce, desc: 'Comma-separated list of reviewer ids'
           optional :description, type: String, desc: 'The description of the merge request'
           optional :labels, type: Array[String], coerce_with: Validations::Types::CommaSeparatedToArray.coerce, desc: 'Comma-separated list of label names'
           optional :add_labels, type: Array[String], coerce_with: Validations::Types::CommaSeparatedToArray.coerce, desc: 'Comma-separated list of label names'

spec/requests/api/merge_requests_spec.rb

@@ -1736,6 +1736,36 @@ RSpec.describe API::MergeRequests do
       end
     end
 
+    context 'accepts reviewer_ids' do
+      let(:params) do
+        {
+          title: 'Test merge request',
+          source_branch: 'feature_conflict',
+          target_branch: 'master',
+          author_id: user.id,
+          reviewer_ids: [user2.id]
+        }
+      end
+
+      it 'creates a new merge request with a reviewer' do
+        post api("/projects/#{project.id}/merge_requests", user), params: params
+
+        expect(response).to have_gitlab_http_status(:created)
+        expect(json_response['title']).to eq('Test merge request')
+        expect(json_response['reviewers'].first['name']).to eq(user2.name)
+      end
+
+      it 'creates a new merge request with no reviewer' do
+        params[:reviewer_ids] = []
+
+        post api("/projects/#{project.id}/merge_requests", user), params: params
+
+        expect(response).to have_gitlab_http_status(:created)
+        expect(json_response['title']).to eq('Test merge request')
+        expect(json_response['reviewers']).to be_empty
+      end
+    end
+
     context 'between branches projects' do
       context 'different labels' do
         let(:params) do
@@ -2081,6 +2111,34 @@ RSpec.describe API::MergeRequests do
     it_behaves_like 'issuable update endpoint' do
       let(:entity) { merge_request }
     end
+
+    context 'accepts reviewer_ids' do
+      let(:params) do
+        {
+          title: 'Updated merge request',
+          reviewer_ids: [user2.id]
+        }
+      end
+
+      it 'adds a reviewer to the existing merge request' do
+        put api("/projects/#{project.id}/merge_requests/#{merge_request.iid}", user), params: params
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response['title']).to eq('Updated merge request')
+        expect(json_response['reviewers'].first['name']).to eq(user2.name)
+      end
+
+      it 'removes a reviewer from the existing merge request' do
+        merge_request.reviewers = [user2]
+        params[:reviewer_ids] = []
+
+        put api("/projects/#{project.id}/merge_requests/#{merge_request.iid}", user), params: params
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response['title']).to eq('Updated merge request')
+        expect(json_response['reviewers']).to be_empty
+      end
+    end
   end
 
   describe "POST /projects/:id/merge_requests/:merge_request_iid/context_commits" do