Allow users to use the /merge quick action in the notes api

Issue: gitlab.com/gitlab-org/gitlab/-/issues/354116
MR: gitlab.com/gitlab-org/gitlab/-/merge_requests/82065

doc/api/notes.md

@@ -399,10 +399,11 @@ Parameters:
 
 | Attribute           | Type           | Required | Description                                                                                                                  |
 |---------------------|----------------|----------|------------------------------------------------------------------------------------------------------------------------------|
-| `id`                | integer or string | yes      | The ID or [URL-encoded path of the project](index.md#namespaced-path-encoding)                                              |
-| `merge_request_iid` | integer        | yes      | The IID of a project merge request                                                                                           |
-| `body`              | string         | yes      | The content of a note. Limited to 1,000,000 characters.                                                                      |
-| `created_at`        | string         | no       | Date time string, ISO 8601 formatted. Example: `2016-03-11T03:45:40Z` (requires administrator or project/group owner rights) |
+| `id`                    | integer or string | yes      | The ID or [URL-encoded path of the project](index.md#namespaced-path-encoding)                                              |
+| `merge_request_iid`     | integer        | yes      | The IID of a project merge request                                                                                           |
+| `body`                  | string         | yes      | The content of a note. Limited to 1,000,000 characters.                                                                      |
+| `created_at`            | string         | no       | Date time string, ISO 8601 formatted. Example: `2016-03-11T03:45:40Z` (requires administrator or project/group owner rights) |
+| `merge_request_diff_sha`| string         | no       | The SHA of the head commit which is used to ensure that the merge request hasn't been updated since the API request was sent. This is required for the /merge quick action |
 
 ### Modify existing merge request note
 

lib/api/notes.rb

@@ -75,6 +75,7 @@ module API
           requires :body, type: String, desc: 'The content of a note'
           optional :confidential, type: Boolean, desc: 'Confidentiality note flag, default is false'
           optional :created_at, type: String, desc: 'The creation date of the note'
+          optional :merge_request_diff_head_sha, type: String, desc: 'The SHA of the head commit'
         end
         post ":id/#{noteables_str}/:noteable_id/notes", feature_category: feature_category do
           allowlist =
@@ -87,7 +88,8 @@ module API
             noteable_type: noteables_str.classify,
             noteable_id: noteable.id,
             confidential: params[:confidential],
-            created_at: params[:created_at]
+            created_at: params[:created_at],
+            merge_request_diff_head_sha: params[:merge_request_diff_head_sha]
           }
 
           note = create_note(noteable, opts)

spec/requests/api/notes_spec.rb

@@ -228,44 +228,83 @@ RSpec.describe API::Notes do
     end
 
     let(:request_body) { 'Hi!' }
+    let(:params) { { body: request_body } }
     let(:request_path) { "/projects/#{project.id}/merge_requests/#{merge_request.iid}/notes" }
 
-    subject { post api(request_path, user), params: { body: request_body } }
+    subject { post api(request_path, user), params: params }
 
     context 'a command only note' do
-      let(:request_body) { "/spend 1h" }
+      context '/spend' do
+        let(:request_body) { "/spend 1h" }
 
-      before do
-        project.add_developer(user)
-      end
+        before do
+          project.add_developer(user)
+        end
 
-      it 'returns 202 Accepted status' do
-        subject
+        it 'returns 202 Accepted status' do
+          subject
 
-        expect(response).to have_gitlab_http_status(:accepted)
-      end
+          expect(response).to have_gitlab_http_status(:accepted)
+        end
 
-      it 'does not actually create a new note' do
-        expect { subject }.not_to change { Note.where(system: false).count }
-      end
+        it 'does not actually create a new note' do
+          expect { subject }.not_to change { Note.where(system: false).count }
+        end
 
-      it 'does however create a system note about the change', :sidekiq_inline do
-        expect { subject }.to change { Note.system.count }.by(1)
-      end
+        it 'does however create a system note about the change', :sidekiq_inline do
+          expect { subject }.to change { Note.system.count }.by(1)
+        end
+
+        it 'applies the commands' do
+          expect { subject }.to change { merge_request.reset.total_time_spent }
+        end
+
+        it 'reports the changes' do
+          subject
 
-      it 'applies the commands' do
-        expect { subject }.to change { merge_request.reset.total_time_spent }
+          expect(json_response).to include(
+            'commands_changes' => include(
+              'spend_time' => include('duration' => 3600)
+            ),
+            'summary' => include('Added 1h spent time.')
+          )
+        end
       end
 
-      it 'reports the changes' do
-        subject
+      context '/merge' do
+        let(:request_body) { "/merge" }
+        let(:project) { create(:project, :public, :repository) }
+        let(:merge_request) { create(:merge_request_with_multiple_diffs, source_project: project, target_project: project, author: user) }
+        let(:params) { { body: request_body, merge_request_diff_head_sha: merge_request.diff_head_sha } }
+
+        before do
+          project.add_developer(user)
+        end
+
+        it 'returns 202 Accepted status' do
+          subject
+
+          expect(response).to have_gitlab_http_status(:accepted)
+        end
+
+        it 'does not actually create a new note' do
+          expect { subject }.not_to change { Note.where(system: false).count }
+        end
+
+        it 'applies the commands' do
+          expect { subject }.to change { merge_request.reload.merge_jid.present? }.from(false).to(true)
+        end
 
-        expect(json_response).to include(
-          'commands_changes' => include(
-            'spend_time' => include('duration' => 3600)
-          ),
-          'summary' => include('Added 1h spent time.')
-        )
+        it 'reports the changes' do
+          subject
+
+          expect(json_response).to include(
+            'commands_changes' => include(
+              'merge' => merge_request.diff_head_sha
+            ),
+            'summary' => ['Merged this merge request.']
+          )
+        end
       end
     end