revlog: generate trivial deltas against null revision To avoid extra memory usage and performance issues with large files, generate a trivial delta header for deltas against the null revision rather than calling the usual delta generator. We append the delta header to meta rather than prepending it to data to avoid a large allocate and copy.

#!/bin/sh

hg init repo
cd repo
touch foo
hg add foo
for i in 0 1 2 3 4 5 6 7 8 9 10 11; do
    echo "foo-$i" >> foo
    hg ci -m "foo-$i" -d "0 0"
done

for out in "%nof%N" "%%%H" "%b-%R" "%h" "%r"; do
    echo "# foo-$out.patch"
    hg export -v -o "foo-$out.patch" 2:tip
done