From e119c6e01e77cef972fe474b0d4254876093442f Mon Sep 17 00:00:00 2001
From: Sam <sam.saffron@gmail.com>
Date: Thu, 20 Apr 2017 10:31:23 -0400
Subject: [PATCH] FIX: embedded comments not working when theme is missing

---
 lib/stylesheet/manager.rb                  | 10 +++++++---
 spec/components/stylesheet/manager_spec.rb | 12 ++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/stylesheet/manager.rb b/lib/stylesheet/manager.rb
index 59b078e58b2..e84a0ed0e83 100644
--- a/lib/stylesheet/manager.rb
+++ b/lib/stylesheet/manager.rb
@@ -41,10 +41,14 @@ class Stylesheet::Manager
 
     @lock.synchronize do
       builder = self.new(target, theme_key)
-      builder.compile unless File.exists?(builder.stylesheet_fullpath)
-      tag = %[<link href="#{builder.stylesheet_path}" media="#{media}" rel="stylesheet" data-target="#{target}"/>]
-      cache[cache_key] = tag
+      if builder.is_theme? && !builder.theme
+        tag = ""
+      else
+        builder.compile unless File.exists?(builder.stylesheet_fullpath)
+        tag = %[<link href="#{builder.stylesheet_path}" media="#{media}" rel="stylesheet" data-target="#{target}"/>]
+      end
 
+      cache[cache_key] = tag
       tag.dup.html_safe
     end
   end
diff --git a/spec/components/stylesheet/manager_spec.rb b/spec/components/stylesheet/manager_spec.rb
index 3098e6000c7..8634216cc3e 100644
--- a/spec/components/stylesheet/manager_spec.rb
+++ b/spec/components/stylesheet/manager_spec.rb
@@ -2,6 +2,18 @@ require 'rails_helper'
 require 'stylesheet/compiler'
 
 describe Stylesheet::Manager do
+
+  it 'does not crash for missing theme' do
+    link = Stylesheet::Manager.stylesheet_link_tag(:embedded_theme)
+    expect(link).to eq("")
+
+    theme = Theme.create(name: "embedded", user_id: -1)
+    SiteSetting.default_theme_key = theme.key
+
+    link = Stylesheet::Manager.stylesheet_link_tag(:embedded_theme)
+    expect(link).not_to eq("")
+  end
+
   it 'can correctly compile theme css' do
     theme = Theme.new(
       name: 'parent',