Issue a warning if "-r ." is used with two working directory parents. Rationale for not aborting instead: The first parent is usually more important as it is the local branch during a merge and commands like 'hg diff' and 'hg diff -r.' behave still identically (except for the warning of course). Added a test for log -r. with one and two parents.

#!/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