view tests/test-empty-file @ 9725:3f522d2fa633

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

hg init a
cd a
touch empty1
hg add empty1
hg commit -m 'add empty1' -d '1000000 0'

touch empty2
hg add empty2
hg commit -m 'add empty2' -d '1000000 0'

hg up -C 0
touch empty3
hg add empty3
hg commit -m 'add empty3' -d '1000000 0'

hg heads

hg merge 1
# before changeset 05257fd28591, we didn't notice the
# empty file that came from rev 1.
hg status
hg commit -m merge -d '1000000 0'
hg manifest --debug tip