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

hg init
echo foo > a
hg add a
hg commit -m "1" -d "1000000 0"
hg verify
chmod -r .hg/store/data/a.i
hg verify 2>/dev/null || echo verify failed
chmod +r .hg/store/data/a.i
hg verify 2>/dev/null || echo verify failed
chmod -w .hg/store/data/a.i
echo barber > a
hg commit -m "2" -d "1000000 0" 2>/dev/null || echo commit failed