Re: [FR] Make notion of "modification time" configurable during publishing

[Suhail Singh]

Ihor Radchenko writes:

> But do you actually use one but not other in practice?

As in, could users have a preference for one vs the other in practice?
Yes, since the choice isn't without consequence, it's conceivable
(generally speaking) that some would prefer one over the other. FWIW, in
my specific case, I use CommitDate, but I am not convinced it's "the
right thing" in all situations.

Not having conducted a survey, I also cannot comment on the frequency
with which users have a desired preference for one vs the other. I am
also not aware of general rules where users would necessarily prefer one
over the other, but it's possible they may exist. My point was to simply
point out that there is more than one interpretation of
"vc-modification-time".

> It should not be too hard to add buffer hash calculation there.

No disagreement there.

> It will only work for files without includes and force us to use
> exactly the same hash algorithm.

I don't follow. I was stating that the concept of a "file hash" could be
obtained in more than way. I.e., in addition to it being calculated "by
hand" it would also be possible to query an oracle (the VCS in this
case) for it. This is distinct and orthogonal from the decision of how a
"file with includes" is handled.

If I understand you correctly, the logic you have in mind, would be
something like this:

- during publish, compare the file hash of the file being published as
  well as all included files
- if the values for all are the same as in the cache, don't publish (if
  user has signalled such intent via the equivalent of
  org-publish-use-timestamps-flag)
- if the value of any one is different, re-publish and update cache with
  the updated file hashes

It doesn't matter how the specific file hash is obtained, as long as the
mechanism is being used consistently and the file hash of the included
files are also being consulted in an appropriate way.

-- 
Suhail