[GQL] Add author and merged_at to MergeRequest Type

This adds the author and merged_at fields to the graphql API.

The authorize field service is changed to support arrays of lazy values,
which is a bug that had gone unnoticed.

app/graphql/types/merge_request_type.rb

@@ -28,6 +28,8 @@ module Types
           description: 'Timestamp of when the merge request was created'
     field :updated_at, Types::TimeType, null: false,
           description: 'Timestamp of when the merge request was last updated'
+    field :merged_at, Types::TimeType, null: true, complexity: 5,
+          description: 'Timestamp of when the merge request was merged, null if not merged'
     field :source_project, Types::ProjectType, null: true,
           description: 'Source project of the merge request'
     field :target_project, Types::ProjectType, null: false,
@@ -109,6 +111,8 @@ module Types
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchModelLoader.new(Milestone, obj.milestone_id).find }
     field :assignees, Types::UserType.connection_type, null: true, complexity: 5,
           description: 'Assignees of the merge request'
+    field :author, Types::UserType, null: true,
+          description: 'User who created this merge request'
     field :participants, Types::UserType.connection_type, null: true, complexity: 5,
           description: 'Participants in the merge request'
     field :subscribed, GraphQL::BOOLEAN_TYPE, method: :subscribed?, null: false, complexity: 5,

changelogs/unreleased/ajk-gql-add-mr-author.yml

+---
+title: Add missing Merge Request fields
+merge_request: 30935
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -5767,6 +5767,11 @@ type MergeRequest implements Noteable {
     last: Int
   ): UserConnection
 
+  """
+  User who created this merge request
+  """
+  author: User
+
   """
   Timestamp of when the merge request was created
   """
@@ -5917,6 +5922,11 @@ type MergeRequest implements Noteable {
   """
   mergeableDiscussionsState: Boolean
 
+  """
+  Timestamp of when the merge request was merged, null if not merged
+  """
+  mergedAt: Time
+
   """
   The milestone of the merge request
   """

doc/api/graphql/reference/gitlab_schema.json

@@ -16085,6 +16085,20 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "author",
+              "description": "User who created this merge request",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "OBJECT",
+                "name": "User",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "createdAt",
               "description": "Timestamp of when the merge request was created",
@@ -16499,6 +16513,20 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "mergedAt",
+              "description": "Timestamp of when the merge request was merged, null if not merged",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "SCALAR",
+                "name": "Time",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "milestone",
               "description": "The milestone of the merge request",

doc/api/graphql/reference/index.md

@@ -860,6 +860,7 @@ Autogenerated return type of MarkAsSpamSnippet
 | Name  | Type  | Description |
 | ---   |  ---- | ----------  |
 | `allowCollaboration` | Boolean | Indicates if members of the target project can push to the fork |
+| `author` | User | User who created this merge request |
 | `createdAt` | Time! | Timestamp of when the merge request was created |
 | `defaultMergeCommitMessage` | String | Default merge commit message of the merge request |
 | `description` | String | Description of the merge request (Markdown rendered as HTML for caching) |
@@ -880,6 +881,7 @@ Autogenerated return type of MarkAsSpamSnippet
 | `mergeStatus` | String | Status of the merge request |
 | `mergeWhenPipelineSucceeds` | Boolean | Indicates if the merge has been set to be merged when its pipeline succeeds (MWPS) |
 | `mergeableDiscussionsState` | Boolean | Indicates if all discussions in the merge request have been resolved, allowing the merge request to be merged |
+| `mergedAt` | Time | Timestamp of when the merge request was merged, null if not merged |
 | `milestone` | Milestone | The milestone of the merge request |
 | `project` | Project! | Alias for target_project |
 | `projectId` | Int! | ID of the merge request project |

lib/gitlab/graphql/authorize/authorize_field_service.rb

@@ -84,13 +84,25 @@ module Gitlab
           elsif resolved_type.is_a? Array
             # A simple list of rendered types  each object being an object to authorize
             resolved_type.select do |single_object_type|
-              allowed_access?(current_user, unpromise(single_object_type).object)
+              allowed_access?(current_user, realized(single_object_type).object)
             end
           else
             raise "Can't authorize #{@field}"
           end
         end
 
+        # Ensure that we are dealing with realized objects, not delayed promises
+        def realized(thing)
+          case thing
+          when BatchLoader::GraphQL
+            thing.sync
+          when GraphQL::Execution::Lazy
+            thing.value # part of the private api, but we need to unwrap it here.
+          else
+            thing
+          end
+        end
+
         def allowed_access?(current_user, object)
           object = object.sync if object.respond_to?(:sync)
 
@@ -113,17 +125,6 @@ module Gitlab
         def scalar_type?
           node_type_for_basic_connection(@field.type).kind.scalar?
         end
-
-        # Sometimes we get promises, and have to resolve them. The dedicated way
-        # of doing this (GitlabSchema.after_lazy) is a private framework method,
-        # and so we use duck-typing interface inference here instead.
-        def unpromise(maybe_promise)
-          if maybe_promise.respond_to?(:value) && !maybe_promise.respond_to?(:object)
-            maybe_promise.value
-          else
-            maybe_promise
-          end
-        end
       end
     end
   end

spec/graphql/types/merge_request_type_spec.rb

@@ -23,7 +23,7 @@ describe GitlabSchema.types['MergeRequest'] do
       source_branch_exists target_branch_exists
       upvotes downvotes head_pipeline pipelines task_completion_status
       milestone assignees participants subscribed labels discussion_locked time_estimate
-      total_time_spent reference
+      total_time_spent reference author merged_at
     ]
 
     expect(described_class).to have_graphql_fields(*expected_fields)

spec/requests/api/graphql/project/merge_request_spec.rb

@@ -37,6 +37,30 @@ describe 'getting merge request information nested in a project' do
     expect(merge_request_graphql_data['webUrl']).to be_present
   end
 
+  it 'includes author' do
+    post_graphql(query, current_user: current_user)
+
+    expect(merge_request_graphql_data['author']['username']).to eq(merge_request.author.username)
+  end
+
+  it 'includes correct mergedAt value when merged' do
+    time = 1.week.ago
+    merge_request.mark_as_merged
+    merge_request.metrics.update_columns(merged_at: time)
+
+    post_graphql(query, current_user: current_user)
+    retrieved = merge_request_graphql_data['mergedAt']
+
+    expect(Time.zone.parse(retrieved)).to be_within(1.second).of(time)
+  end
+
+  it 'includes nil mergedAt value when not merged' do
+    post_graphql(query, current_user: current_user)
+    retrieved = merge_request_graphql_data['mergedAt']
+
+    expect(retrieved).to be_nil
+  end
+
   context 'permissions on the merge request' do
     it 'includes the permissions for the current user on a public project' do
       expected_permissions = {