Element#replace with CDATA raises error on JRuby

[mrzasa]

Summary

When I try to replace element with CDATA on JRuby, I got an error RuntimeError: org.jruby.exceptions.RaiseException: (RuntimeError) could not replace child: org.w3c.dom.DOMException: NOT_SUPPORTED_ERR: The implementation does not support the requested type of object or operation.. What is even more strange, element is replaced. It works without problems on MRI. Please, see examples below.

Examples

# replace.rb
require 'rubygems'
require 'nokogiri'
doc = Nokogiri::XML('<parent><child>text</child></parent>')
doc.children.first.children.first.replace(doc.create_cdata("<b>text</b>"))
puts doc

Expected behaviour (MRI)

$ ruby replace.rb 
<?xml version="1.0"?>
<parent><![CDATA[<b>text</b>]]></parent>

Actual behaviour (JRuby)

$ ruby replace.rb 
RuntimeError: org.jruby.exceptions.RaiseException: (RuntimeError) could not replace child: org.w3c.dom.DOMException: NOT_SUPPORTED_ERR: The implementation does not support the requested type of object or operation. 
  replace_node at nokogiri/XmlNode.java:1730
       replace at /home/user/.rvm/gems/jruby-9.1.5.0/gems/nokogiri-1.8.0-java/lib/nokogiri/xml/node.rb:281
        <main> at replace.rb:4

When I run the script line by line in console, it appears that puts doc gives the same result as on MRI:

<?xml version="1.0"?>
<parent><![CDATA[<b>text</b>]]></parent>

element is replaced, but error is raised afterwards.

Env info

Ubuntu 16.10

JRuby Nokogiri:

$ nokogiri -v
# Nokogiri (1.8.0)
    ---
    warnings: []
    nokogiri: 1.8.0
    ruby:
      version: 2.3.1
      platform: java
      description: jruby 9.1.5.0 (2.3.1) 2016-09-07 036ce39 Java HotSpot(TM) 64-Bit Server VM 25.131-b11 on 1.8.0_131-b11 +jit [linux-x86_64]
      engine: jruby
      jruby: 9.1.5.0
    xerces: Xerces-J 2.11.0
    nekohtml: NekoHTML 1.9.21

MRI Nokogiri:

$ nokogiri -v
# Nokogiri (1.8.0)
    ---
    warnings: []
    nokogiri: 1.8.0
    ruby:
      version: 2.3.3
      platform: x86_64-linux
      description: ruby 2.3.3p222 (2016-11-21 revision 56859) [x86_64-linux]
      engine: ruby
    libxml:
      binding: extension
      source: packaged
      libxml2_path: "/home/user/.rvm/gems/ruby-2.3.3/gems/nokogiri-1.8.0/ports/x86_64-pc-linux-gnu/libxml2/2.9.4"
      libxslt_path: "/home/user/.rvm/gems/ruby-2.3.3/gems/nokogiri-1.8.0/ports/x86_64-pc-linux-gnu/libxslt/1.1.29"
      libxml2_patches:
      - 0001-Fix-comparison-with-root-node-in-xmlXPathCmpNodes.patch
      - 0002-Fix-XPointer-paths-beginning-with-range-to.patch
      - 0003-Disallow-namespace-nodes-in-XPointer-ranges.patch
      libxslt_patches:
      - 0001-Fix-heap-overread-in-xsltFormatNumberConversion.patch
      - 0002-Check-for-integer-overflow-in-xsltAddTextString.patch
      compiled: 2.9.4
      loaded: 2.9.4

[mrzasa]

I've found a workaround: if CDATA element is wrapped in NodeSet, no exception is raised:

# replace.rb
require 'rubygems'
require 'nokogiri'
doc = Nokogiri::XML('<parent><child>text</child></parent>')
set = Nokogiri::XML::NodeSet.new(doc, [doc.create_cdata("<b>text</b>")])
doc.children.first.children.first.replace(set)
puts doc

[flavorjones]

Apologies for the embarrassingly long response time.

I've confirmed this behavior, investigating.

[flavorjones]

OK, the offending code is at https://github.com/sparklemotion/nokogiri/blob/v1.8.2/ext/java/nokogiri/XmlNode.java#L1707-L1710 which I'll reproduce here:

parentNode.replaceChild(otherNode, thisNode);
if (otherNode.getNodeType() != Node.TEXT_NODE) {
    NokogiriHelpers.renameNode(otherNode, thisNode.getNamespaceURI(), otherNode.getNodeName());
}

The first function call, replaceChild(), succeeds (which explains why the document structure is as-expected). It's the second call, renameNode(), which is failing. This makes sense, because renameNode() attempts to make sure the node's namespace matches what we'd expect from a real tag, and not from a CDATA node.

The solution is going to be skipping that call for CDATA as well as text nodes.

[flavorjones]

Closed by 80205c4

[mrzasa]

Thanks, @flavorjones :)