Breaks several test problems in the test suite, beyond the two we expect to fail (SphericalInfall and DrivenTurbulence3D). It breaks the CoolingTest (three diff. variants), ExtremeAdvectionTest, and PhotonTest.
I don't believe so. If I look at the comments in the hudson run 256 (http://srs.slac.stanford.edu/hudson/job/enzo-dev/256/parameters/), it says "will test PR 285 by John Wise", which is this PR. The hash (ENZO_REV=a5a44797a8b6) also matches the last commit for this PR. The link you've included points toward PR #284. Why the numbers are out of order is anybody's guess, but you should verify that what I'm saying makes sense - otherwise basically all of the messages I posted this morning are suspect.
I was looking at the commit descriptions in (http://srs.slac.stanford.edu/hudson/job/enzo-dev/257/) which are from PR 285. But the changeset hash and comment in the parameters link you posted are from PR 284. I think something is going wrong with hudson to mix up these two PRs.