Redirect to external issue tracker from `/issues`

Prior, in order to display the correct link to "Issues" in the project
navigation, we were performing a check against the project to see if it
used an external issue tracker, and if so, we used that URL. This was
inefficient.

Now, we simply _always_ link to `namespace_project_issues_path`, and
then in the controller we redirect to the external tracker if it's
present.

This also removes the need for the url_for_issue helper. Bonus! :tada:

1 files changed, 7 insertions, 0 deletions

diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index 7f5c3ff3d6a..cb1e514c60e 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -5,6 +5,7 @@ class Projects::IssuesController < Projects::ApplicationController
   include ToggleAwardEmoji
   include IssuableCollections
 
+  before_action :redirect_to_external_issue_tracker, only: [:index]
   before_action :module_enabled
   before_action :issue, only: [:edit, :update, :show, :referenced_merge_requests,
                                :related_branches, :can_create_branch]
@@ -201,6 +202,12 @@ class Projects::IssuesController < Projects::ApplicationController
     return render_404 unless @project.issues_enabled && @project.default_issues_tracker?
   end
 
+  def redirect_to_external_issue_tracker
+    return unless @project.external_issue_tracker
+
+    redirect_to @project.external_issue_tracker.issues_url
+  end
+
   # Since iids are implemented only in 6.1
   # user may navigate to issue page using old global ids.
   #