Add symlink method to util.opener. Differences from os.symlink: - the symlink name is relative to the opener base directory - if a file with that name already exists, it's removed - if necessary, parent directories are created - if the system (OS or filesystem) doesn't support symlinks, a regular file is created. Its contents are the symlink target.

#!/bin/sh
#
mkdir t
cd t
hg init
echo 0 > a
echo 0 > b
hg ci -A -m m -d "1000000 0"
hg rm a
hg cat a
sleep 1 # make sure mtime is changed
echo 1 > b
hg ci -m m -d "1000000 0"
echo 2 > b
hg cat -r 0 a
hg cat -r 0 b
hg cat -r 1 a
hg cat -r 1 b