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 a
cd a
echo a > foo
hg rm foo
hg add foo
hg commit -m 1 -d "1000000 0"
hg remove
rm foo
hg remove foo
hg revert --all
rm foo
hg remove --after
hg commit -m 2 -d "1000000 0"
hg export --nodates 0
hg export --nodates 1
hg log -p -r 0
hg log -p -r 1
echo a > a
hg add a
hg rm a
hg rm -f a
echo b > b
hg ci -A -m 3 -d "1000001 0"
echo c >> b
hg rm b
hg rm -f b
cd ..
hg clone a b