Git 1.7.9 has an annoying bug in that it uses absolute paths when initializing submodules. In the best case, this breaks git within the submodule when the full checkout is transferred to another host. In the worst case, it leads to incorrect git behavior within the submodule.
This affects parsoid round-trip testing. We currently use rsync to distribute the code from the central checkout, which provokes this issue. Clients are checking the git revision of the submodule and exit if it has changed. They also report the revision to the round-trip test server. In the worst case this means that test results are attributed to the wrong revision.
This was fixed in git 1.7.10, March 2012: