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
touch unknown

touch a
hg add a
hg ci -m "1" -d "1000000 0"

touch b
hg add b
hg ci -m "2" -d "1000000 0"

echo %% Should show unknown
hg status
hg revert -r 0 --all
echo %% Should show unknown and b removed
hg status
echo %% Should show a and unknown
ls