support hooks written in python. to write hook in python, create module with hook function inside. make sure mercurial can import module (put it in $PYTHONPATH or load it as extension). hook function should look like this: def myhook(ui, repo, hooktype, **kwargs): if hook_passes: return True elif hook_explicitly_fails: return False elif some_other_failure: import util raise util.Abort('helpful failure message') else: return # implicit return of None makes hook fail! then in .hgrc, add hook with "python:" prefix: [hooks] commit = python:mymodule.myhook

#!/bin/sh

hg init
echo 123 > a
hg add a
hg commit -m "first" -d "1000000 0" a
mkdir sub
echo 321 > sub/b
hg add sub/b
hg commit -m "second" -d "1000000 0" sub/b
cat sub/b
hg co 0
cat sub/b 2>/dev/null || echo "sub/b not present"
ls sub 2>/dev/null || echo "sub not present"

true