Re: limit the number of log entries displayed by C-x v l

[Dan Nicolaescu <dann@ics.uci.edu>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

  > >> > With the proposed backend change that just needs
  > >> > vc-annotate-show-log-revision-at-line to pass a 1 as the last argument
  > >> > to vc-print-log-internal.
  > >> Assuming we retarget the `working-revision' argument to specify the
  > >> "starting" revision, I guess.  Yes, that could work.
  > > Actually, after looking a bit more we'd need more changes, the
  > > `working-revision' is not passed to the `print-log' VC method, so a bit
  > > more work would be needed for that :-(
  > > But this does not affect my original proposal, which is still needed.
  > 
  > Yes, I'm not opposing it,

I checked a patch that adds the LIMIT argument.
LIMIT defaults to the value of new variable vc-log-show-limit (not a
very good name).  vc-log-show-limit is set to 0 (meaning no limit), so
the default behavior has not changed.  Please feel free to change the
default value.

The limit can be set interactively when using a prefix argument.

I changed all the backends that do not support LIMIT to ignore it.  And
I added support for it for all the ones that do, except for Git.  Git
has enough fans on this list, so surely someone else will do it.

I'll work on adding button(s) to request more entries.

  >  I'm just trying to get a better general
  > picture.  Some of the problems we may encounter is that some backends
  > don't support the `limit' argument.  Hopefully all those backends can
  > easily turn a "print-log FILE REV LIMIT=1" request into "print-log FILE
  > REV1 REV2" instead, tho.  Not sure what to do for other values of LIMIT,
  > but maybe that's doable as well.

It seems that for this we need to add another argument to the
`print-log' VC method: START-REVISION.
Do we want to also add END-REVISION?

Given that vc-annotate would only use START-REVISION in conjunction with
LIMIT==1, we can document that the backends should only support that
combination, at least for the time being.