[MERGE] Fix bug #248427 by adding a --change option to log.

[Vincent Ladeuil]

>>>>> "aaron" == Aaron Bentley <aaron at aaronbentley.com> writes:

    aaron> Vincent Ladeuil wrote:
    >> Aaron said:
    >> > log uses an inclusive set, so log -r 1..2 displays the log
    >> > messages for revisions 1 and 2. diff -r 1..2 displays only the
    >> > changes introduced by 2. diff -c 2 is equivalent to "diff -r
    >> > 1..2".
    >> 
    >> In order to be consistent, from an *UI* POV, log -c 2 should
    >> therefore display the logs for revision 2 only.

    aaron> From my UI POV, this makes it inconsistent.

Sorry, citing you like this was awkward, let's start again.

My rationale here is:

You can't be inconsistent with void. There was *no* --change
option for log. 

Both diff and log use --revision. They implement it
differently. 

--change is a time saver for diff, not providing it to log is...
strange. 

I view --change as a syntactic sugar for --revision, since diff
and log implement --revision differently, that means, IMHO, that
we should do the same with --change.

On top of that, when I read in the bug comments: "I find myself
typing bzr log -c $whatever _all the time_ and it's very
frustrating that it doesn't work." and thinks: "Doh, of course,
I'd like to do the same !!!", I scratch the itch.

I looked at the code trying to understand the difference between
diff and log, saw it was an easy fix, tried, succeed, sent the
patch.

     Vincent