Re: Itches with the current rev spec

Junio C Hamano [off-list ref] writes:

A much larger issue is that the current setup_revisions()
infrastructure does not let us express an operation that involves
two or more DAGs.  People sometimes wish to say an equivalent of

    git show $(git rev-list A..B) $(git rev-list C..D)

but obviously

    git show A..B C..D

is not the way to say it, and this limitation comes from it.

Just a clarification. Technically, this is _not_ impossible.  With
some (read: quite a lot of) work to move objects.flags out of the
object and to allow unbounded number of flag bits, you could support
arbitrary number of ranges that are UNION'ed together by pretty much
the same code structure as the current revision machinery.  You need
2 x N bits (for the above example, 2 x 2 bits) per commit.

I am not saying it is easy or we should start working on it, though
;-).