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 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