Enable demandimport only in scripts, not in importable modules (issue605) This way other applications can choose if and when they want this feature, because it might be problematic if those applications rely on ImportError.

#!/bin/sh

hg init dir
cd dir
echo bleh > bar
hg add bar
hg ci -m 'add bar'

hg cp bar foo
echo >> bar
hg ci -m 'cp bar foo; change bar'

hg debugrename foo
hg debugindex .hg/store/data/bar.i