changegroup: avoid large copies - handle chunk headers separately rather than prepending them to (potentially large) chunks - break large chunks into 1M pieces for compression - don't prepend file metadata onto (potentially large) file data

#!/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