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

[Paul Mackerras <paulus@samba.org>]

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 like the idea but I am not sure if you have implemented it the best
way.

Are we sure that all the commits we had before doing the update will
still be there after the update?  What if I had checked in some
changes and run gitk, and then decided that the commit I just created
was wrong, and so I set HEAD to HEAD^1 and did a git prune, then told
gitk to update - shouldn't I see the top commit disappear?

Maybe it would be better to just clean out everything and re-read all
the commits from scratch.

Also, I'm not convinced that doing ^$id for all tags, heads and other
refs is correct.  Although we have read the reference and know the ID,
that doesn't mean we have seen that commit and displayed it.

The more general problem is to provide a way for the user to change
the set of commits displayed using a dialog box.  That would require
gitk to understand its command-line arguments so that the elements of
the dialog box could be initialized properly, though.

Some other comments:

> +    .bar.file add command -label "Update" -command "updatecommits [list $rargs]"

This would be better as:

    .bar.file add command -label "Update" -command [list updatecommits $rargs]

> +    rereadrefs

We don't need the redrawing part of rereadrefs, just the bit that
unsets tagids etc. and calls readrefs.

Regards,
Paul.