libxml2 2.7.8 / libxml++ 2.35 and changes in DTD validation

Question

Lately my Fedora 16 auto-upgraded libxml2 from a previous version to the latest rpm libxml2-2.7.8-8.fc16.i686, and suddenly the dtd validation starts to complain about missing declarations in the DTD file. Before this upgrade everything worked fine. And of course when I disable the validation it also works fine, but that is not the idea. I don't use libxml2 directly, I actually use libxml++ which is a wrapper for libxml2.

I tried to search for some changes in the code of libxml2 that might cause this problem, but the recent changes on the libxml2 site and the changes on the Fedora site for this package do not mention any changes in the DTD code (in recent releases)

The xml message below suddenly is not valid anymore:

<?xml version="1.0"?><!DOCTYPE MYAPP SYSTEM "myapp.dtd"><MYAPP><Command type="Connect"/></MYAPP>

It gives the following error messages:

No declaration for attribute type of element Command
No declaration for element Command
No declaration for element MYAPP

Here is a (stripped) snippet from the myapp.dtd I use:

<!ELEMENT MYAPP (Command|Result)>
<!ELEMENT Command (Parameters?)>
<!ELEMENT Parameters (..a lot of other types and records..)>
<!ATTLIST Command type (None|
                    Connect|
                    Disconnect
                    ) "None">

Anybody has some pointers about what might suddenly cause this, does anybody has some pointer/links of the changes in this version. Is it a known bug, any clues??

As suggested I re-compiled (the latest version) libxml2 and no changes, I also recompiled the latest version of libxml++ (2.35-3), it now nicely prints the line number and column of the error, but that is all that has changed. The parser still doesn't accept my (previously accepted) xml file/message.

Answer 1

But libxml 2.7.8 (on Windows) that I use validates your file properly. No messages. First it complained about .. on the third line of your dtd file, so I needed to remove that line. And now it gives a clean output.

So maybe your auto-upgrade actually screwed up the library. If you compile 2.7.8 from source it would be put in /usr/local and would override your current installation. Then you could try again. I don't know how you could try to fix the existing installation. Anyway 2.7.8 release is not responsible for the errors you get.

My testing command line: xmllint ikku.xml -dtdvalid

A quick thought: maybe your parser takes another dtd file into consideration, due to some catalog problems. Try to change the dtd filename.