Cache total issue / MR counts for project by user type

This runs a slightly slower query to get the issue and MR counts in the
navigation, but caches by user type (can see all / none confidential issues) for
two minutes.

3 files changed, 34 insertions, 25 deletions

diff --git a/app/finders/issues_finder.rb b/app/finders/issues_finder.rb
index 3455a75b8bc..328198c026a 100644
--- a/app/finders/issues_finder.rb
+++ b/app/finders/issues_finder.rb
@@ -36,6 +36,19 @@ class IssuesFinder < IssuableFinder
       project_ids: current_user.authorized_projects(CONFIDENTIAL_ACCESS_LEVEL).select(:id))
   end
 
+  def user_can_see_all_confidential_issues?
+    return false unless current_user
+    return true if current_user.full_private_access?
+
+    project? &&
+      project &&
+      project.team.max_member_access(current_user.id) >= CONFIDENTIAL_ACCESS_LEVEL
+  end
+
+  def user_cannot_see_confidential_issues?
+    current_user.blank?
+  end
+
   private
 
   def init_collection
@@ -57,17 +70,4 @@ class IssuesFinder < IssuableFinder
   def item_project_ids(items)
     items&.reorder(nil)&.select(:project_id)
   end
-
-  def user_can_see_all_confidential_issues?
-    return false unless current_user
-    return true if current_user.full_private_access?
-
-    project? &&
-      project &&
-      project.team.max_member_access(current_user.id) >= CONFIDENTIAL_ACCESS_LEVEL
-  end
-
-  def user_cannot_see_confidential_issues?
-    current_user.blank?
-  end
 end
diff --git a/app/helpers/issuables_helper.rb b/app/helpers/issuables_helper.rb
index 3259a9c1933..d99a9bab12f 100644
--- a/app/helpers/issuables_helper.rb
+++ b/app/helpers/issuables_helper.rb
@@ -165,11 +165,7 @@ module IssuablesHelper
     }
 
     state_title = titles[state] || state.to_s.humanize
-
-    count =
-      Rails.cache.fetch(issuables_state_counter_cache_key(issuable_type, state), expires_in: 2.minutes) do
-        issuables_count_for_state(issuable_type, state)
-      end
+    count = issuables_count_for_state(issuable_type, state)
 
     html = content_tag(:span, state_title)
     html << " " << content_tag(:span, number_with_delimiter(count), class: 'badge')
@@ -255,22 +251,35 @@ module IssuablesHelper
     end
   end
 
-  def issuables_count_for_state(issuable_type, state)
+  def issuables_count_for_state(issuable_type, state, finder: nil)
+    finder ||= public_send("#{issuable_type}_finder")
+    cache_key = issuables_state_counter_cache_key(issuable_type, finder, state)
+
     @counts ||= {}
-    @counts[issuable_type] ||= public_send("#{issuable_type}_finder").count_by_state
-    @counts[issuable_type][state]
+    @counts[cache_key] ||= Rails.cache.fetch(cache_key, expires_in: 2.minutes) do
+      finder.count_by_state
+    end
+
+    @counts[cache_key][state]
   end
 
   IRRELEVANT_PARAMS_FOR_CACHE_KEY = %i[utf8 sort page].freeze
   private_constant :IRRELEVANT_PARAMS_FOR_CACHE_KEY
 
-  def issuables_state_counter_cache_key(issuable_type, state)
+  def issuables_state_counter_cache_key(issuable_type, finder, state)
     opts = params.with_indifferent_access
     opts[:state] = state
     opts.except!(*IRRELEVANT_PARAMS_FOR_CACHE_KEY)
     opts.delete_if { |_, value| value.blank? }
 
-    hexdigest(['issuables_count', issuable_type, opts.sort].flatten.join('-'))
+    key_components = ['issuables_count', issuable_type, opts.sort]
+
+    if issuable_type == :issues
+      key_components << finder.user_can_see_all_confidential_issues?
+      key_components << finder.user_cannot_see_confidential_issues?
+    end
+
+    hexdigest(key_components.flatten.join('-'))
   end
 
   def issuable_templates(issuable)
diff --git a/app/views/layouts/nav/_project.html.haml b/app/views/layouts/nav/_project.html.haml
index a2c6e44425a..b095adcfe7e 100644
--- a/app/views/layouts/nav/_project.html.haml
+++ b/app/views/layouts/nav/_project.html.haml
@@ -28,7 +28,7 @@
           %span
             Issues
             - if @project.default_issues_tracker?
-              %span.badge.count.issue_counter= number_with_delimiter(IssuesFinder.new(current_user, project_id: @project.id, state: :opened).execute.count)
+              %span.badge.count.issue_counter= number_with_delimiter(issuables_count_for_state(:issues, :opened, finder: IssuesFinder.new(current_user, project_id: @project.id)))
 
     - if project_nav_tab? :merge_requests
       - controllers = [:merge_requests, 'projects/merge_requests/conflicts']
@@ -37,7 +37,7 @@
         = link_to namespace_project_merge_requests_path(@project.namespace, @project), title: 'Merge Requests', class: 'shortcuts-merge_requests' do
           %span
             Merge Requests
-            %span.badge.count.merge_counter.js-merge-counter= number_with_delimiter(MergeRequestsFinder.new(current_user, project_id: @project.id, state: :opened).execute.count)
+            %span.badge.count.merge_counter.js-merge-counter= number_with_delimiter(issuables_count_for_state(:merge_requests, :opened, finder: MergeRequestsFinder.new(current_user, project_id: @project.id)))
 
     - if project_nav_tab? :pipelines
       = nav_link(controller: [:pipelines, :builds, :environments, :artifacts]) do