"null document" error when parsing an empty IO in jruby 1.7.3

[jcoyne]

Jruby 1.7.3

$ Nokogiri::XML.parse('')
=> #<Nokogiri::XML::Document:0x7fa name="document">
$ Nokogiri::XML.parse(StringIO.new(''))
Java::JavaLang::RuntimeException: null document
...

In Ruby 2.0.0:

$ Nokogiri::XML.parse('')
 => #<Nokogiri::XML::Document:0x3fd424b250b0 name="document"> 
$ Nokogiri::XML.parse(StringIO.new(''))
 => #<Nokogiri::XML::Document:0x3fd424b286c0 name="document"> 

[jcoyne]

I'm looking at https://github.com/sparklemotion/nokogiri/blob/master/lib/nokogiri/xml/document.rb#L52-L53 and wondering if there ought to be a similar code like: return new if string_or_io.eof? in the block beginning on line 49.

[mbklein]

Apparently it's not just read_memory that pukes on empty docs; it's Xerces, too. I can't imagine any harm from moving line 53 to before line 48 and skipping the whole block if the source IO is empty, but I don't have the cycles to try it out right now.

[flavorjones]

@jcoyne You're probably right. Send a pull request?