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
echo 123 > a
hg add a
hg commit -m "first" -d "1000000 0" a
mkdir sub
echo 321 > sub/b
hg add sub/b
hg commit -m "second" -d "1000000 0" sub/b
cat sub/b
hg co 0
cat sub/b 2>/dev/null || echo "sub/b not present"
test -d sub || echo "sub not present"

true