Re: [PATCH] gitk: add Update menu item.

Sven Verdoolaege writes:

Update will redraw the commits if any commits have been added to any
of the selected heads.  The new commits appear on the top.

I put this in although I'm not completely happy with it (though it is
a good step in the right direction).

Why do we unset children and nchildren in the phase == updatecommits
case?  Wouldn't it give the same result if we set ncleft to nchildren
for each commit and then we didn't call updatechildren in
finishcommits?  I think that would end up simpler.

I tried removing some commits (using git reset --hard) and then doing
selecting update from the menu, and it redrew everything, but the
removed commits were still shown.

Also, what will happen if the user selects update while gitk is still
drawing the graph?  I think that will cause havoc.  At _best_ we'll
end up with a truncated list of commits AFAICS.  We need to make that
robust.

Paul.