Merge branch 'fix-graphql-mr-merge-user-field' into 'master'

Fix GraphQL API mergeUser is null when mergeWhenPipelineSucceeds is false

See merge request gitlab-org/gitlab!76043

app/graphql/types/merge_request_type.rb

@@ -196,7 +196,7 @@ module Types
     field :auto_merge_strategy, GraphQL::Types::String, null: true,
           description: 'Selected auto merge strategy.'
     field :merge_user, Types::UserType, null: true,
-          description: 'User who merged this merge request.'
+          description: 'User who merged this merge request or set it to merge when pipeline succeeds.'
     field :timelogs, Types::TimelogType.connection_type, null: false,
           description: 'Timelogs on the merge request.'
 
@@ -276,6 +276,10 @@ module Types
     def reviewers
       object.reviewers
     end
+
+    def merge_user
+      object.metrics&.merged_by || object.merge_user
+    end
   end
 end
 

doc/api/graphql/reference/index.md

@@ -11704,7 +11704,7 @@ Maven metadata.
 | <a id="mergerequestmergestatus"></a>`mergeStatus` **{warning-solid}** | [`String`](#string) | **Deprecated** in 14.0. This was renamed. Use: [`MergeRequest.mergeStatusEnum`](#mergerequestmergestatusenum). |
 | <a id="mergerequestmergestatusenum"></a>`mergeStatusEnum` | [`MergeStatus`](#mergestatus) | Merge status of the merge request. |
 | <a id="mergerequestmergetrainscount"></a>`mergeTrainsCount` | [`Int`](#int) | Number of merge requests in the merge train. |
-| <a id="mergerequestmergeuser"></a>`mergeUser` | [`UserCore`](#usercore) | User who merged this merge request. |
+| <a id="mergerequestmergeuser"></a>`mergeUser` | [`UserCore`](#usercore) | User who merged this merge request or set it to merge when pipeline succeeds. |
 | <a id="mergerequestmergewhenpipelinesucceeds"></a>`mergeWhenPipelineSucceeds` | [`Boolean`](#boolean) | Indicates if the merge has been set to be merged when its pipeline succeeds (MWPS). |
 | <a id="mergerequestmergeable"></a>`mergeable` | [`Boolean!`](#boolean) | Indicates if the merge request is mergeable. |
 | <a id="mergerequestmergeablediscussionsstate"></a>`mergeableDiscussionsState` | [`Boolean`](#boolean) | Indicates if all discussions in the merge request have been resolved, allowing the merge request to be merged. |

spec/graphql/types/merge_request_type_spec.rb

@@ -133,4 +133,28 @@ RSpec.describe GitlabSchema.types['MergeRequest'] do
       end
     end
   end
+
+  describe '#merge_user' do
+    let_it_be(:project) { create(:project, :public) }
+
+    context 'when MR is merged' do
+      let(:merge_request) { create(:merge_request, :with_merged_metrics, target_project: project, source_project: project) }
+
+      it 'is not nil' do
+        value = resolve_field(:merge_user, merge_request)
+
+        expect(value).not_to be_nil
+      end
+    end
+
+    context 'when MR is set to merge when pipeline succeeds' do
+      let(:merge_request) { create(:merge_request, :merge_when_pipeline_succeeds, target_project: project, source_project: project) }
+
+      it 'is not nil' do
+        value = resolve_field(:merge_user, merge_request)
+
+        expect(value).not_to be_nil
+      end
+    end
+  end
 end