(xml/emit-str (xml/cdata "fooo]]>bar"))

"<?xml version=\"1.0\" encoding=\"UTF-8\"?><![CDATA[fooo]]>bar]]>"

This is invalid xml. The contract for cdata states that it cannot contain the end tag "]]>", so if the cdata function gets passed content that contains it, it should do the right thing, which is probably this:

http://stackoverflow.com/questions/223652/is-there-a-way-to-escape-a-cdata-end-token-in-xml

(split the content so it is emitted as multiple cdata blocks, none of which contain the entire end-tag "]]>").

This is not a purely academic bug report - I actually hit this problem in prxml and fixed it on my fork.