[Buildbot-devel] Cleaning, but not every build

[Henry]

Is there any way to make a builder that builds incrementally every  
time it detects changes, only rebuilding things that have changed,   
but also cleans everything and rebuilds regularly (say, daily). I know  
how to make a builder that does one and another that does the the  
other, but that leaves the incremental builder never cleaning.  
buildbot doesn't seem to like having two builders use the same  
directory.

Also, is there any way to make it so instead of detecting a change,  
building, and then detecting and building all of the changes since the  
first build, it downloads and builds all the changes one by one, so  
you can tell exactly which one broke it?