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:

  > > Logs for some big trees can be huge, the Linux one is millions of lines.
  > 
  > Yes, this is a fairly serious problem.  We need to refine the
  > `print-log' backend op to be able to control it somehow.  E.g. in
  > vc-annotate, it'd be good to be able to get just the log message
  > corresponding to a particular commit.

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.

  > For a generic `vc-print-log' operation where the user doesn't specify
  > any particular revision, I wonder what the best UI should be.  What do
  > other front-ends (e.g. loggerhead, viewCVS, ...) do to cope with the
  > large number of log messages?

Sorry, no idea.
gitk seems to show all the entries, but it shows only the short log by default.

  > Maybe we should show just the first thousand or so by default and then
  > provide a button (and command) in log-view-mode to get more?

That could work.  
It would work with the proposed backend change.

C-x v l call would call the backend to show vc-log-show-entries, then
the button would get the revision id for the last entry in the buffer,
and it would then call the backend starting from that revision to
request more entries.