Include dry_run error field for failed dry run operation

lib/api/commits.rb

@@ -203,7 +203,7 @@ module API
       params do
         requires :sha, type: String, desc: 'A commit sha, or the name of a branch or tag to be cherry picked'
         requires :branch, type: String, desc: 'The name of the branch', allow_blank: false
-        optional :dry_run, type: Boolean, default: false, desc: "Don't commit any changes"
+        optional :dry_run, type: Boolean, default: false, desc: "Does not commit any changes"
       end
       post ':id/repository/commits/:sha/cherry_pick', requirements: API::COMMIT_ENDPOINT_REQUIREMENTS do
         authorize_push_to_branch!(params[:branch])
@@ -233,7 +233,10 @@ module API
               with: Entities::Commit
           end
         else
-          error!(result.slice(:message, :error_code), 400, header)
+          response = result.slice(:message, :error_code)
+          response[:dry_run] = :error if params[:dry_run]
+
+          error!(response, 400, header)
         end
       end
 
@@ -244,7 +247,7 @@ module API
       params do
         requires :sha, type: String, desc: 'Commit SHA to revert'
         requires :branch, type: String, desc: 'Target branch name', allow_blank: false
-        optional :dry_run, type: Boolean, default: false, desc: "Don't commit any changes"
+        optional :dry_run, type: Boolean, default: false, desc: "Does not commit any changes"
       end
       post ':id/repository/commits/:sha/revert', requirements: API::COMMIT_ENDPOINT_REQUIREMENTS do
         authorize_push_to_branch!(params[:branch])
@@ -274,7 +277,10 @@ module API
               with: Entities::Commit
           end
         else
-          error!(result.slice(:message, :error_code), 400, header)
+          response = result.slice(:message, :error_code)
+          response[:dry_run] = :error if params[:dry_run]
+
+          error!(response, 400, header)
         end
       end
 

spec/requests/api/commits_spec.rb

@@ -1543,6 +1543,14 @@ RSpec.describe API::Commits do
 
           expect(json_response['error_code']).to eq 'empty'
         end
+
+        it 'includes an additional dry_run error field when enabled' do
+          post api(route, current_user), params: { branch: 'markdown', dry_run: true }
+
+          expect(response).to have_gitlab_http_status(:bad_request)
+          expect(json_response['error_code']).to eq 'empty'
+          expect(json_response['dry_run']).to eq 'error'
+        end
       end
 
       context 'when ref contains a dot' do
@@ -1724,6 +1732,18 @@ RSpec.describe API::Commits do
           expect(response).to have_gitlab_http_status(:bad_request)
           expect(json_response['error_code']).to eq 'empty'
         end
+
+        it 'includes an additional dry_run error field when enabled' do
+          # First one actually reverts
+          post api(route, current_user), params: { branch: 'markdown' }
+
+          # Second one is redundant and should be empty
+          post api(route, current_user), params: { branch: 'markdown', dry_run: true }
+
+          expect(response).to have_gitlab_http_status(:bad_request)
+          expect(json_response['error_code']).to eq 'empty'
+          expect(json_response['dry_run']).to eq 'error'
+        end
       end
     end