Re: why does git set X in LESS env var?

[Christoph Anton Mitterer <calestyo@scientia.org>]

On Fri, 2023-10-13 at 00:36 +0200, Dragan Simic wrote:
> It seems that "--redraw-on-quit" is a possible candidate for
> replacing 
> "-X" in the set of default options for less(1)

*If* some changes were made to how git handles this, it might perhaps
be worth to consider not to touch LESS at all, but only add the
required settings via command line arguments (i.e. -F -R ...).

Or perhaps only remove options from it, if they're known to break the
behaviour with git (like -+R might).


I always feel configuration via env vars is a bit fragile:
- especially when one has generic names like POSIXLY_CORRECT there's
  some chance that by exporting it to one program, where one wants the
  effect, another program started off by that also gets it
  unintentionally
- generic terms may be used by multiple programs, causing problems

Also, if one can set only one LESS var in the environment, not one for
less "alone", one for less with git, etc. - that is unless for programs
like bat/delta which have specific own env vars to set the pager.

So if I set e.g. LESS to something, than typically only to stuff from
which I believe it works as expected for any possible users.
E.g. -F might be such a case.

But if I do that, git won't touch LESS and set the required -R, so I
have to do that manually for git, e.g. either via git_config or by
defining an alias git='LESS=FRX git'.
But in both cases it would "break" again, should ever another option be
needed and added by git to the default LESS (which is however only set
when it's unset).
And in case of an alias, there would be the additional problem, that
it's typically not picked up in non-interactive shells.


Long story short, it might make sense for git, to (mostly) ignore LESS
and rather invoke less with -F -R.

The problem with that in turn would of course be that it doesn't
automatically propagate down, if e.g. git's pager is set to detla and
delta in turn runs less.
However, that's IMO litte concern, since then it's delta's duty to set
-R (if it think it needs to do so), which it actually does.


Cheers,
Chris.