Merge branch '335496-expose-mergerequestscount-field-in-graphql-issue-type' into 'master'

Expose `mergeRequestsCount` field in GraphQL Issue type

See merge request gitlab-org/gitlab!65931

app/graphql/resolvers/merge_requests_count_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  class MergeRequestsCountResolver < BaseResolver
+    type GraphQL::Types::Int, null: true
+
+    def resolve
+      BatchLoader::GraphQL.for(object.id).batch do |ids, loader, args|
+        counts = MergeRequestsClosingIssues.count_for_collection(ids, context[:current_user]).to_h
+
+        ids.each do |id|
+          loader.call(id, counts[id] || 0)
+        end
+      end
+    end
+  end
+end

app/graphql/types/issue_type.rb

@@ -60,6 +60,9 @@ module Types
           description: 'Number of upvotes the issue has received.'
     field :downvotes, GraphQL::Types::Int, null: false,
           description: 'Number of downvotes the issue has received.'
+    field :merge_requests_count, GraphQL::Types::Int, null: false,
+          description: 'Number of merge requests that close the issue on merge.',
+          resolver: Resolvers::MergeRequestsCountResolver
     field :user_notes_count, GraphQL::Types::Int, null: false,
           description: 'Number of user notes of the issue.',
           resolver: Resolvers::UserNotesCountResolver

doc/api/graphql/reference/index.md

@@ -9080,6 +9080,7 @@ Relationship between an epic and an issue.
 | <a id="epicissueiid"></a>`iid` | [`ID!`](#id) | Internal ID of the issue. |
 | <a id="epicissueiteration"></a>`iteration` | [`Iteration`](#iteration) | Iteration of the issue. |
 | <a id="epicissuelabels"></a>`labels` | [`LabelConnection`](#labelconnection) | Labels of the issue. (see [Connections](#connections)) |
+| <a id="epicissuemergerequestscount"></a>`mergeRequestsCount` | [`Int!`](#int) | Number of merge requests that close the issue on merge. |
 | <a id="epicissuemetricimages"></a>`metricImages` | [`[MetricImage!]`](#metricimage) | Metric images associated to the issue. |
 | <a id="epicissuemilestone"></a>`milestone` | [`Milestone`](#milestone) | Milestone of the issue. |
 | <a id="epicissuemoved"></a>`moved` | [`Boolean`](#boolean) | Indicates if issue got moved from other project. |
@@ -10153,6 +10154,7 @@ Returns [`VulnerabilitySeveritiesCount`](#vulnerabilityseveritiescount).
 | <a id="issueiid"></a>`iid` | [`ID!`](#id) | Internal ID of the issue. |
 | <a id="issueiteration"></a>`iteration` | [`Iteration`](#iteration) | Iteration of the issue. |
 | <a id="issuelabels"></a>`labels` | [`LabelConnection`](#labelconnection) | Labels of the issue. (see [Connections](#connections)) |
+| <a id="issuemergerequestscount"></a>`mergeRequestsCount` | [`Int!`](#int) | Number of merge requests that close the issue on merge. |
 | <a id="issuemetricimages"></a>`metricImages` | [`[MetricImage!]`](#metricimage) | Metric images associated to the issue. |
 | <a id="issuemilestone"></a>`milestone` | [`Milestone`](#milestone) | Milestone of the issue. |
 | <a id="issuemoved"></a>`moved` | [`Boolean`](#boolean) | Indicates if issue got moved from other project. |

spec/graphql/resolvers/merge_requests_count_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::MergeRequestsCountResolver do
+  include GraphqlHelpers
+
+  describe '#resolve' do
+    let_it_be(:user) { create(:user) }
+    let_it_be(:project1) { create(:project, :repository, :public) }
+    let_it_be(:project2) { create(:project, :repository, repository_access_level: ProjectFeature::PRIVATE) }
+    let_it_be(:issue) { create(:issue, project: project1) }
+    let_it_be(:merge_request_closing_issue1) { create(:merge_requests_closing_issues, issue: issue) }
+    let_it_be(:merge_request_closing_issue2) do
+      merge_request = create(:merge_request, source_project: project2)
+      create(:merge_requests_closing_issues, issue: issue, merge_request: merge_request)
+    end
+
+    specify do
+      expect(described_class).to have_nullable_graphql_type(GraphQL::Types::Int)
+    end
+
+    subject { batch_sync { resolve_merge_requests_count(issue) } }
+
+    context "when user can only view an issue's closing merge requests that are public" do
+      it 'returns the count of the merge requests closing the issue' do
+        expect(subject).to eq(1)
+      end
+    end
+
+    context "when user can view an issue's closing merge requests that are both public and private" do
+      before do
+        project2.add_reporter(user)
+      end
+
+      it 'returns the count of the merge requests closing the issue' do
+        expect(subject).to eq(2)
+      end
+    end
+  end
+
+  def resolve_merge_requests_count(obj)
+    resolve(described_class, obj: obj, ctx: { current_user: user })
+  end
+end

spec/graphql/types/issue_type_spec.rb

@@ -15,7 +15,7 @@ RSpec.describe GitlabSchema.types['Issue'] do
 
   it 'has specific fields' do
     fields = %i[id iid title description state reference author assignees updated_by participants labels milestone due_date
-                confidential discussion_locked upvotes downvotes user_notes_count user_discussions_count web_path web_url relative_position
+                confidential discussion_locked upvotes downvotes merge_requests_count user_notes_count user_discussions_count web_path web_url relative_position
                 emails_disabled subscribed time_estimate total_time_spent human_time_estimate human_total_time_spent closed_at created_at updated_at task_completion_status
                 design_collection alert_management_alert severity current_user_todos moved moved_to
                 create_note_email timelogs project_id]

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

@@ -476,6 +476,17 @@ RSpec.describe 'getting an issue list for a project' do
       include_examples 'N+1 query check'
     end
 
+    context 'when requesting `merge_requests_count`' do
+      let(:requested_fields) { [:merge_requests_count] }
+
+      before do
+        create_list(:merge_requests_closing_issues, 2, issue: issue_a)
+        create_list(:merge_requests_closing_issues, 3, issue: issue_b)
+      end
+
+      include_examples 'N+1 query check'
+    end
+
     context 'when requesting `timelogs`' do
       let(:requested_fields) { 'timelogs { nodes { timeSpent } }' }