From 2d35364c02003ccbb9c5b06c291b65c2f6c3b278 Mon Sep 17 00:00:00 2001
From: fen <fen@nice.lgbt>
Date: Wed, 2 Nov 2016 00:22:41 +0100
Subject: [PATCH] implement warning about missing keys in url drops

---
 lib/jekyll/url.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/jekyll/url.rb b/lib/jekyll/url.rb
index c74e11c8..32bcfb8f 100644
--- a/lib/jekyll/url.rb
+++ b/lib/jekyll/url.rb
@@ -86,7 +86,11 @@ module Jekyll
 
     def generate_url_from_drop(template)
       template.gsub(%r!:([a-z_]+)!) do |match|
-        replacement = @placeholders.public_send(match.sub(":".freeze, "".freeze))
+        begin
+          replacement = @placeholders.public_send(match.sub(":".freeze, "".freeze))
+        rescue NoMethodError
+          Jekyll.logger.warn "", "#{match} is not defined!"
+        end
         if replacement.nil?
           "".freeze
         else