From 74f71ccf296c2b01e1a8455b4107b02316a7c7fb Mon Sep 17 00:00:00 2001
From: Peter Zhang <zpregister@gmail.com>
Date: Sat, 21 Mar 2020 00:38:14 +0100
Subject: add a condition to avoid FrozenError

nil.to_s in Ruby 2.7.0 now always return a frozen String ""
a=nil.to_s
a.gsub!(//,'')
will raise a FrozenError (can't modify frozen String: "")
---
 lib/wikicloth/wiki_buffer/var.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/wikicloth/wiki_buffer/var.rb b/lib/wikicloth/wiki_buffer/var.rb
index 2e0f5d1..7a39527 100644
--- a/lib/wikicloth/wiki_buffer/var.rb
+++ b/lib/wikicloth/wiki_buffer/var.rb
@@ -80,7 +80,7 @@ def to_html
 
         ret = @options[:link_handler].include_resource(key,key_options).to_s
 
-        ret.gsub!(/<!--(.|\s)*?-->/,"")
+        ret.gsub!(/<!--(.|\s)*?-->/,"") unless ret.frozen?
         count = 0
         tag_attr = key_options.collect { |p|
           if p.instance_of?(Hash)