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
echo foo > foo
hg add foo
hg commit -m1 -d"0 0"
echo "# should show copy"
hg copy foo bar
hg debugstate|grep '^copy'
echo "# shouldn't show copy"
hg commit -m2 -d"0 0"
hg debugstate|grep '^copy'
echo "# should match"
hg debugindex .hg/store/data/foo.i
hg debugrename bar
echo bleah > foo
echo quux > bar
hg commit -m3 -d"0 0"
echo "# should not be renamed"
hg debugrename bar
hg copy -f foo bar
echo "# should show copy"
hg debugstate|grep '^copy'
hg commit -m3 -d"0 0"
echo "# should show no parents for tip"
hg debugindex .hg/store/data/bar.i
echo "# should match"
hg debugindex .hg/store/data/foo.i
hg debugrename bar
echo "# should show no copies"
hg debugstate|grep '^copy'
exit 0