TinyXML(2) might cause problems with the XSD schema now often attached due to the new package format (V2) #77
Description
This is more a general problem caused by the wide use of TinyXML(2).
But to me it became the most apparent in rospack as this package provides the commandline tool and basic library to deal with ROS packages.
The problem is based on the lightweight approach of TinyXML(2) in which they don't support the parsing of schemas. see What it doesn't do
This property combined with the provided schema in REP140 led several developers to add it into their package.xmls.
In my minimal installation I found that this was already done in pluginlib, nodelet_core, bondpy, test_bond, bondcpp, bond_core, smclib, dynamic_reconfigure, bond and class_loader.
The updates containing the schema are quite new and I don't know if their are any changes already planned to address this potential issue.
According particularly to rospack one solution would be to switch to a more complex parser which supports schemas. But this will obviously not affect packages which don't use rospack but using TinyXML(2) themselves to parse package.xmls.
A more global approach would be to avoid the addition of the schema to the package.xml and maybe provide a dedicated library to verify them if needed. Doing so would preserve the wide usage of TinyXML(2).