[RFC] UI for logging directories and multiple files

[Ian Clatworthy]

Real soon now, I hope to put a patch up extending log
to support logging of directories and multiple files.
I have the core of this working, though getting fast
performance on large repositories will take a bit longer.
(The latter is important given these issues have been
highlighted by the Emacs community as features they
want/need before moving to Bazaar.)

This email though is about the UI and how *I* expect
the options to work together. If others agree or think
differently, I'd like to hear about it please.

For the record, here's how 'bzr log FILE' behaves now:

1. with no options, just the revision info is shown
2. with -v, the *full* delta is shown as well
3. with -p, the diff *just* for that file is shown.

My feeling is that the -v behaviour ought to be changed.
If someone asks for file/directory filtering, the
status output should be filtered accordingly. FWIW,
that's how status works:

* "bzr status -cX" shows all changed files in revision X
* "bzr status -cX foo" shows just what happened to foo.

When we support multiple files and directories in log, I
think filtered -v and -p output will be most desirable.
After all, for a single file, you know what file changed
(because you're only looking for one of them) and 95% of
the time, the action will be 'modified'. In comparison,
for a directory or several files, showing what changed
- without the noise of every other change in each
revision - will become more important.

Some questions:

1. Is there a genuine need for occasionally seeing the full
delta and/or full diff when logging paths? If so, what UI
would you like for this?

2. When logging paths, is there a desire to see the delta
   implicitly? I considered this but ended up thinking that
   just showing the revisions was sufficient and adding -v
   to see that additional info was no big deal. In fact,
   an implicit delta seems unnecessary noise when using
   "bzr log -p paths" so that was another reason for
   sticking with only showing the delta is it was
   explicitly asked for. Does anyone think otherwise?

Ian C.