RE: [PATCH 1/2] doc: pull: explain what is a fast-forward

[Felipe Contreras <felipe.contreras@gmail.com>]

Kerry, Richard wrote:
> 
> > From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> > Sent: 25 June 2021 11:59

> > Perhaps, it's not like I've got much in the way of a holistic world view with
> > which to replace it.
> > 
> > I do think "perfect" would do a few things it doesn't though, imagine reading
> > about it for the first time and not making the connection to tapes. Is it an
> > optimization? Is there a slow-forward? What if upstream rewound there
> > branch and I merge, is that a merge-backwards?
> > 
> > It's not immediately obvious how rebase/merge/fast-forward relate or
> > if/when (e.g. merge sometimes being a merge-ff) they're incompatible
> > concepts.
> 
> On the one hand, I think fast-forward is an entirely suitable term for git to use, based on what it does.  Instantaneously moving the branch head pointer forward to the new head
> On the other hand I think it is distinctly different from the use with transport controls for linear media (ie tape - video or audio).
> For all of them fast-forward moves the play/record point relative to the media, maybe to the end (or to "now"), maybe not.  There may or may not be a cueing play that happens while the tape is moving.
> For a modern stream (eg podcast) player, such as BBC Sounds (via its web-site) there is no fast-forward control.  There is play/pause, +20 and -20 seconds, go to the start of the stream and (for live broadcasts) go to now.  The latter is very close to Git's fast-forward, but is not labelled as such.  There is also a time-line, where the user can go to an arbitrary point in time and play from there.
> Hardware players do have fast-forward controls, even for streams, or files.

Yes, but regardless of that for whatever reason it's already part of the
culture, and people are using fast-forward irrespective of the original
meaning:

  "They fast-forward to present day ten years later, where he has been
  hospitalized and is on life support." [1]

  "So then fast-forward to now and, like, six months ago, they found the
  script and called me up." [2]

This is similar to what happened with the floppy disk icon. New
generations may have no idea what it originally meant, regardless of
that today it means "save". Except the fast-forward button still exists
in many remote controls.

Same with other concepts like carbon copy. I'm not sure if newer
generations have ever seen an actual physical carbon copy take place. Or
a physical bookmark.

Words evolve beyond their original meaning, and today I think that has
already happened with fast-forward.

> So, yes, the term is very widely known in the wider world (even for those who didn't grow up with tape).
> And yes, irrespective of the above, it makes complete sense for git's usage.

Indeed.

[1] https://en.wikipedia.org/wiki/I_Need_a_Doctor
[2] https://en.wikipedia.org/wiki/Predators_(film)

-- 
Felipe Contreras