Merge branch '325470-optimize-confidentiality-filter-on-issue-finder' into 'master'

Optimize IssuesFinder redundent confidential check when assigned [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!57073

app/finders/issues_finder.rb

@@ -47,6 +47,15 @@ class IssuesFinder < IssuableFinder
   # rubocop: disable CodeReuse/ActiveRecord
   def with_confidentiality_access_check
     return Issue.all if params.user_can_see_all_confidential_issues?
+
+    if Feature.enabled?(:optimize_issue_filter_assigned_to_self, default_enabled: :yaml)
+      # If already filtering by assignee we can skip confidentiality since a user
+      # can always see confidential issues assigned to them. This is just an
+      # optimization since a very common usecase of this Finder is to load the
+      # count of issues assigned to the user for the header bar.
+      return Issue.all if current_user && params.assignees.include?(current_user)
+    end
+
     return Issue.where('issues.confidential IS NOT TRUE') if params.user_cannot_see_confidential_issues?
 
     Issue.where('

changelogs/unreleased/325470-optimize-confidentiality-filter-on-issue-finder.yml

+---
+title: Optimize database performance of loading assigned issue count on header bar
+merge_request: 57073
+author:
+type: performance

config/feature_flags/development/optimize_issue_filter_assigned_to_self.yml

+---
+name: optimize_issue_filter_assigned_to_self
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/57073
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/325470
+milestone: '13.11'
+type: development
+group: group::global search
+default_enabled: false

spec/support/shared_examples/finders/assignees_filter_shared_examples.rb

 # frozen_string_literal: true
 
 RSpec.shared_examples 'assignee ID filter' do
+  context 'when optimize_issue_filter_assigned_to_self is disabled' do
+    before do
+      stub_feature_flags(optimize_issue_filter_assigned_to_self: false)
+    end
+
+    it 'returns issuables assigned to that user' do
+      expect(issuables).to contain_exactly(*expected_issuables)
+    end
+  end
+
   it 'returns issuables assigned to that user' do
     expect(issuables).to contain_exactly(*expected_issuables)
   end
@@ -13,6 +23,16 @@ RSpec.shared_examples 'assignee NOT ID filter' do
 end
 
 RSpec.shared_examples 'assignee username filter' do
+  context 'when optimize_issue_filter_assigned_to_self is disabled' do
+    before do
+      stub_feature_flags(optimize_issue_filter_assigned_to_self: false)
+    end
+
+    it 'returns issuables assigned to those users' do
+      expect(issuables).to contain_exactly(*expected_issuables)
+    end
+  end
+
   it 'returns issuables assigned to those users' do
     expect(issuables).to contain_exactly(*expected_issuables)
   end