<img src="hoge.png" alt="ほげ" />
ってタグが含まれてると落ちるような気配がする。
irb(main):001:0> require 'text/hatena' => true irb(main):002:0> p=Text::Hatena.new => #<Text::Hatena:0x55c134 @sectionanchor="o-", @ilevel=0, @baseuri="", @texthandler=#<Proc:0x00358f5c@./text/hatena.rb:16>, @html="", @invalidnode=[], @permalink=""> irb(main):003:0> p.parse('<img src="hoge.png" alt="ほげ" />') NoMethodError: undefined method `empty?' for true:TrueClass from ./text/hatena/html_filter.rb:121:in `sanitize' from ./text/hatena/html_filter.rb:111:in `emptyelemtaghandler' from ./text/hatena/html_filter.rb:105:in `emptyelemtaghandler' from ./text/hatena/html_filter.rb:50:in `parse' from ./text/hatena/html_filter.rb:44:in `parse' from ./text/hatena.rb:46:in `parse' from (irb):3
<img src="hoge.png" alt="ほげ">
なら大丈夫。