diff: add --inverse option
Most of the time, one can reverse a diff by swapping the revisions passed with
-r but it happens that if you use the global -R, and diff against the tip of
the current repo, you can't swap the revisions. One use-case for that is
reviewing changes from a bundle before unbundling. One could also pipe the
output of `hg diff` to a command line filter that reverses the diff, but that
would remove the benefit from color diffs. Therefore, having an option in
`hg diff` to reverse a diff is a good thing.
The option flag selection was tricky. GNU patch uses -R/--reverse but -R is
already used as a global option and --reverse would make --rev ambiguous.
#!/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/"
echo % qdiff filename
hg qdiff --nodates base
echo % revert
hg revert -a
echo % qpop
hg qpop
echo % qdelete mqbase
hg qdelete mqbase
echo % commit 2
printf '1\n2\n3\n4\nhello world\ngoodbye world\n7\n8\n9\n' > lines
hg ci -Amlines -d '2 0'
echo % qnew 2
hg qnew -mmqbase2 mqbase2
printf '\n\n1\n2\n3\n4\nhello world\n goodbye world\n7\n8\n9\n' > lines
echo % qdiff -U 1
hg qdiff --nodates -U 1
echo % qdiff -b
hg qdiff --nodates -b
echo % qdiff -U 1 -B
hg qdiff --nodates -U 1 -B
echo % qdiff -w
hg qdiff --nodates -w
echo % qdiff --inverse
hg qdiff --nodates --inverse