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
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
echo % init
hg init a
cd a
echo % commit
echo 'base' > base
hg ci -Ambase -d '1 0'
echo % qnew mqbase
hg qnew -mmqbase mqbase
echo % qrefresh
echo 'patched' > base
hg qrefresh
echo % qdiff
hg qdiff | sed -e "s/\(+++ [a-zA-Z0-9_/.-]*\).*/\1/" \
-e "s/\(--- [a-zA-Z0-9_/.-]*\).*/\1/"
echo % qdiff dirname
hg qdiff . | sed -e "s/\(+++ [a-zA-Z0-9_/.-]*\).*/\1/" \
-e "s/\(--- [a-zA-Z0-9_/.-]*\).*/\1/"