don't return uninitialized memory from bdiff.blocks() bdiff.blocks() returns a dummy match at the end of both files; the length of that chunk is never set, so it will sometimes contain random heap garbage. There are apparently workarounds for this elsewhere: # bdiff sometimes gives huge matches past eof, this check eats them,

#!/bin/sh

hg init

mkdir alpha
touch alpha/one
mkdir beta
touch beta/two

hg add alpha/one beta/two
hg ci -m "start" -d "1000000 0"

echo 1 > alpha/one
echo 2 > beta/two

echo EVERYTHING
hg diff --nodates

echo BETA ONLY
hg diff --nodates beta

echo INSIDE BETA
cd beta
hg diff --nodates .