Method for returning issues readable by a user

The method Ability.issues_readable_by_user takes a list of users and an
optional user and returns an Array of issues readable by said user. This
method in turn is used by
Banzai::ReferenceParser::IssueParser#nodes_visible_to_user so this
method no longer needs to get all the available abilities just to check
if a user has the "read_issue" ability.

To test this I benchmarked an issue with 222 comments on my development
environment. Using these changes the time spent in nodes_visible_to_user
was reduced from around 120 ms to around 40 ms.

1 files changed, 5 insertions, 1 deletions

diff --git a/spec/models/concerns/mentionable_spec.rb b/spec/models/concerns/mentionable_spec.rb
index 5e652660e2c..549b0042038 100644
--- a/spec/models/concerns/mentionable_spec.rb
+++ b/spec/models/concerns/mentionable_spec.rb
@@ -68,7 +68,7 @@ describe Issue, "Mentionable" do
 
   describe '#create_cross_references!' do
     let(:project) { create(:project) }
-    let(:author)  { double('author') }
+    let(:author)  { build(:user) }
     let(:commit)  { project.commit }
     let(:commit2) { project.commit }
 
@@ -88,6 +88,10 @@ describe Issue, "Mentionable" do
     let(:author)  { create(:author) }
     let(:issues)  { create_list(:issue, 2, project: project, author: author) }
 
+    before do
+      project.team << [author, Gitlab::Access::DEVELOPER]
+    end
+
     context 'before changes are persisted' do
       it 'ignores pre-existing references' do
         issue = create_issue(description: issues[0].to_reference)