gistfile1.sh

# checkout 0.25.1 git
git clone git://github.com/reductivelabs/puppet.git

cd puppet

# start bisecting
# we suspect the problem is a parser issue
# so we'll focus only on the parser
git bisect start 0.24.8 0.25.1 -- lib/puppet/parser

# if you can reproduce with "puppet":
RUBYLIB=./lib time bin/puppet --debug --parseonly /path/to/site.pp

# if slow:
git bisect bad

# if fast as 0.24
git bisect good

# if the commit produces a version that doesn't work:
git bisect skip

# you can automate the system by putting the puppet command in a script that parses
# time output and say from there if it is good or bad.
# see git help bisect for more information