$ hg init $ touch a $ hg add a $ hg ci -m "a" $ echo 123 > b $ hg add b $ hg diff --nodates diff -r 3903775176ed b --- /dev/null +++ b/b @@ -0,0 +1,1 @@ +123 $ hg diff --nodates -r tip diff -r 3903775176ed b --- /dev/null +++ b/b @@ -0,0 +1,1 @@ +123 $ echo foo > a $ hg diff --nodates diff -r 3903775176ed a --- a/a +++ b/a @@ -0,0 +1,1 @@ +foo diff -r 3903775176ed b --- /dev/null +++ b/b @@ -0,0 +1,1 @@ +123 $ hg diff -r "" hg: parse error: empty query [255] $ hg diff -r tip -r "" hg: parse error: empty query [255]