Merge branch 'issue_25900_2' into 'master'

Gather issuable  metadata to avoid n+ queries on index view

Closes #25900

See merge request !9006

5 files changed, 117 insertions, 0 deletions

diff --git a/spec/controllers/dashboard_controller_spec.rb b/spec/controllers/dashboard_controller_spec.rb
new file mode 100644
index 00000000000..566d8515198
--- /dev/null
+++ b/spec/controllers/dashboard_controller_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe DashboardController do
+  let(:user) { create(:user) }
+  let(:project) { create(:project) }
+
+  before do
+    project.team << [user, :master]
+    sign_in(user)
+  end
+
+  describe 'GET issues' do
+    it_behaves_like 'issuables list meta-data', :issue, :issues
+  end
+
+  describe 'GET merge requests' do
+    it_behaves_like 'issuables list meta-data', :merge_request, :merge_requests
+  end
+end
diff --git a/spec/controllers/projects/issues_controller_spec.rb b/spec/controllers/projects/issues_controller_spec.rb
index 4b89381eb96..e576bf9ef79 100644
--- a/spec/controllers/projects/issues_controller_spec.rb
+++ b/spec/controllers/projects/issues_controller_spec.rb
@@ -24,6 +24,8 @@ describe Projects::IssuesController do
         project.team << [user, :developer]
       end
 
+      it_behaves_like "issuables list meta-data", :issue
+
       it "returns index" do
         get :index, namespace_id: project.namespace.path, project_id: project.path
 
diff --git a/spec/controllers/projects/merge_requests_controller_spec.rb b/spec/controllers/projects/merge_requests_controller_spec.rb
index 63780802cfa..bfd134e406e 100644
--- a/spec/controllers/projects/merge_requests_controller_spec.rb
+++ b/spec/controllers/projects/merge_requests_controller_spec.rb
@@ -147,6 +147,8 @@ describe Projects::MergeRequestsController do
   end
 
   describe 'GET index' do
+    let!(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
+
     def get_merge_requests(page = nil)
       get :index,
           namespace_id: project.namespace.to_param,
@@ -154,6 +156,8 @@ describe Projects::MergeRequestsController do
           state: 'opened', page: page.to_param
     end
 
+    it_behaves_like "issuables list meta-data", :merge_request
+
     context 'when page param' do
       let(:last_page) { project.merge_requests.page().total_pages }
       let!(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
diff --git a/spec/features/issuables/issuable_list_spec.rb b/spec/features/issuables/issuable_list_spec.rb
new file mode 100644
index 00000000000..e31bc40adc3
--- /dev/null
+++ b/spec/features/issuables/issuable_list_spec.rb
@@ -0,0 +1,57 @@
+require 'rails_helper'
+
+describe 'issuable list', feature: true do
+  let(:project) { create(:empty_project) }
+  let(:user)    { create(:user) }
+
+  issuable_types = [:issue, :merge_request]
+
+  before do
+    project.add_user(user, :developer)
+    login_as(user)
+    issuable_types.each { |type| create_issuables(type) }
+  end
+
+  issuable_types.each do |issuable_type|
+    it "avoids N+1 database queries for #{issuable_type.to_s.humanize.pluralize}" do
+      control_count = ActiveRecord::QueryRecorder.new { visit_issuable_list(issuable_type) }.count
+
+      create_issuables(issuable_type)
+
+      expect { visit_issuable_list(issuable_type) }.not_to exceed_query_limit(control_count)
+    end
+
+    it "counts upvotes, downvotes and notes count for each #{issuable_type.to_s.humanize}" do
+      visit_issuable_list(issuable_type)
+
+      expect(first('.fa-thumbs-up').find(:xpath, '..')).to have_content(1)
+      expect(first('.fa-thumbs-down').find(:xpath, '..')).to have_content(1)
+      expect(first('.fa-comments').find(:xpath, '..')).to have_content(2)
+    end
+  end
+
+  def visit_issuable_list(issuable_type)
+    if issuable_type == :issue
+      visit namespace_project_issues_path(project.namespace, project)
+    else
+      visit namespace_project_merge_requests_path(project.namespace, project)
+    end
+  end
+
+  def create_issuables(issuable_type)
+    3.times do
+      if issuable_type == :issue
+        issuable = create(:issue, project: project, author: user)
+      else
+        issuable = create(:merge_request, title: FFaker::Lorem.sentence, source_project: project, source_branch: FFaker::Name.name)
+      end
+
+      2.times do
+        create(:note_on_issue, noteable: issuable, project: project, note: 'Test note')
+      end
+
+      create(:award_emoji, :downvote, awardable: issuable)
+      create(:award_emoji, :upvote, awardable: issuable)
+    end
+  end
+end
diff --git a/spec/support/issuables_list_metadata_shared_examples.rb b/spec/support/issuables_list_metadata_shared_examples.rb
new file mode 100644
index 00000000000..dac94dfc31e
--- /dev/null
+++ b/spec/support/issuables_list_metadata_shared_examples.rb
@@ -0,0 +1,35 @@
+shared_examples 'issuables list meta-data' do |issuable_type, action = nil|
+  before do
+    @issuable_ids = []
+
+    2.times do
+      if issuable_type == :issue
+        issuable = create(issuable_type, project: project)
+      else
+        issuable = create(issuable_type, title: FFaker::Lorem.sentence, source_project: project, source_branch: FFaker::Name.name)
+      end
+
+      @issuable_ids << issuable.id
+
+      issuable.id.times       { create(:note, noteable: issuable, project: issuable.project) }
+      (issuable.id + 1).times { create(:award_emoji, :downvote, awardable: issuable) }
+      (issuable.id + 2).times { create(:award_emoji, :upvote, awardable: issuable) }
+    end
+  end
+
+  it "creates indexed meta-data object for issuable notes and votes count" do
+    if action
+      get action
+    else
+      get :index, namespace_id: project.namespace.path, project_id: project.path
+    end
+
+    meta_data = assigns(:issuable_meta_data)
+
+    @issuable_ids.each do |id|
+      expect(meta_data[id].notes_count).to eq(id)
+      expect(meta_data[id].downvotes).to eq(id + 1)
+      expect(meta_data[id].upvotes).to eq(id + 2)
+    end
+  end
+end