The nightly test artifacts don't currently contain everything needed to recompile the sources, this is a known issue...
https://issues.apache.org/jira/browse/SOLR-1989 ...if you want to compile from source off hte trunk or 3x branch, you need to check out the *entire* branch (not just the "solr" directory, but it's parent including lucene and the modules) This is the problem with the source in the nightly artifacts at the moment: they only include the solr source. -Hoss
