Add Project#get_issue

app/models/project.rb

@@ -329,14 +329,18 @@ class Project < ActiveRecord::Base
     self.id
   end
 
-  def issue_exists?(issue_id)
+  def get_issue(issue_id)
     if default_issues_tracker?
-      self.issues.where(iid: issue_id).first.present?
+      issues.find_by(iid: issue_id)
     else
-      true
+      ExternalIssue.new(issue_id, self)
     end
   end
 
+  def issue_exists?(issue_id)
+    get_issue(issue_id).present?
+  end
+
   def default_issue_tracker
     gitlab_issue_tracker_service || create_gitlab_issue_tracker_service
   end
@@ -350,11 +354,7 @@ class Project < ActiveRecord::Base
   end
 
   def default_issues_tracker?
-    if external_issue_tracker
-      false
-    else
-      true
-    end
+    external_issue_tracker.blank?
   end
 
   def external_issues_trackers

lib/gitlab/markdown/issue_reference_filter.rb

@@ -44,21 +44,20 @@ module Gitlab
       # Returns a String with `#123` references replaced with links. All links
       # have `gfm` and `gfm-issue` class names attached for styling.
       def issue_link_filter(text)
-        self.class.references_in(text) do |match, issue, project_ref|
+        self.class.references_in(text) do |match, id, project_ref|
           project = self.project_from_ref(project_ref)
 
-          if project && project.issue_exists?(issue)
-            # FIXME (rspeicher): Law of Demeter
-            push_result(:issue, project.issues.where(iid: issue).first)
+          if project && issue = project.get_issue(id)
+            push_result(:issue, issue)
 
-            url = url_for_issue(issue, project, only_path: context[:only_path])
+            url = url_for_issue(id, project, only_path: context[:only_path])
 
-            title = escape_once("Issue: #{title_for_issue(issue, project)}")
+            title = escape_once("Issue: #{title_for_issue(id, project)}")
             klass = reference_class(:issue)
 
             %(<a href="#{url}"
                  title="#{title}"
-                 class="#{klass}">#{project_ref}##{issue}</a>)
+                 class="#{klass}">#{project_ref}##{id}</a>)
           else
             match
           end

spec/lib/gitlab/markdown/issue_reference_filter_spec.rb

@@ -27,7 +27,7 @@ module Gitlab::Markdown
       let(:reference) { "##{issue.iid}" }
 
       it 'ignores valid references when using non-default tracker' do
-        expect(project).to receive(:issue_exists?).with(issue.iid).and_return(false)
+        expect(project).to receive(:get_issue).with(issue.iid).and_return(nil)
 
         exp = act = "Issue ##{issue.iid}"
         expect(filter(act).to_html).to eq exp
@@ -48,7 +48,7 @@ module Gitlab::Markdown
       it 'ignores invalid issue IDs' do
         exp = act = "Fixed ##{issue.iid + 1}"
 
-        expect(project).to receive(:issue_exists?).with(issue.iid + 1)
+        expect(project).to receive(:get_issue).with(issue.iid + 1).and_return(nil)
         expect(filter(act).to_html).to eq exp
       end
 
@@ -98,8 +98,8 @@ module Gitlab::Markdown
         before { allow_cross_reference! }
 
         it 'ignores valid references when cross-reference project uses external tracker' do
-          expect_any_instance_of(Project).to receive(:issue_exists?).
-            with(issue.iid).and_return(false)
+          expect_any_instance_of(Project).to receive(:get_issue).
+            with(issue.iid).and_return(nil)
 
           exp = act = "Issue ##{issue.iid}"
           expect(filter(act).to_html).to eq exp