Fallback to internal issue tracker if config is invalid.

app/helpers/issues_helper.rb

@@ -16,7 +16,7 @@ module IssuesHelper
   def url_for_project_issues
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker?
+    if @project.used_default_issues_tracker? || config_disabled?
       project_issues_path(@project)
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["project_url"]
@@ -28,7 +28,7 @@ module IssuesHelper
   def url_for_new_issue
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker?
+    if @project.used_default_issues_tracker? || config_disabled?
       url = new_project_issue_path project_id: @project
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["new_issue_url"]
@@ -40,7 +40,7 @@ module IssuesHelper
   def url_for_issue(issue_iid)
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker?
+    if @project.used_default_issues_tracker? || config_disabled?
       url = project_issue_url project_id: @project, id: issue_iid
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["issues_url"]
@@ -59,4 +59,9 @@ module IssuesHelper
       ""
     end
   end
+
+  def config_disabled?
+    return false if Gitlab.config.issues_tracker && Gitlab.config.issues_tracker.values.any?
+    true
+  end
 end

spec/helpers/issues_helper_spec.rb

@@ -47,6 +47,17 @@ describe IssuesHelper do
 
       url_for_project_issues.should eq ""
     end
+
+    describe "when external tracker was enabled and then config removed" do
+      before do
+        @project = ext_project
+        Gitlab.config.stub(:issues_tracker).and_return(nil)
+      end
+
+      it "should return path to internal tracker" do
+        url_for_project_issues.should match(polymorphic_path([@project]))
+      end
+    end
   end
 
   describe :url_for_issue do
@@ -75,6 +86,17 @@ describe IssuesHelper do
 
       url_for_issue(issue.iid).should eq ""
     end
+
+    describe "when external tracker was enabled and then config removed" do
+      before do
+        @project = ext_project
+        Gitlab.config.stub(:issues_tracker).and_return(nil)
+      end
+
+      it "should return internal path" do
+        url_for_issue(issue.iid).should match(polymorphic_path([@project, issue]))
+      end
+    end
   end
 
   describe :url_for_new_issue do
@@ -101,6 +123,17 @@ describe IssuesHelper do
 
       url_for_new_issue.should eq ""
     end
+
+    describe "when external tracker was enabled and then config removed" do
+      before do
+        @project = ext_project
+        Gitlab.config.stub(:issues_tracker).and_return(nil)
+      end
+
+      it "should return internal path" do
+        url_for_new_issue.should match(new_project_issue_path(@project))
+      end
+    end
   end
 
 end