On Mon, Jul 22, 2024 at 11:34:18PM -0400, Jeff King wrote:
> On Mon, Jul 22, 2024 at 04:10:41PM -0700, Junio C Hamano wrote:
>
> > Over the years, we accumulated the community wisdom to avoid the
> > common "one-short export" construct for shell functions, but seem to
> > have lost on which exact platform it is known to fail. Now during
> > an investigation on a breakage for a recent topic, we found one
> > example of failing shell. Let's document that.
>
> My recollection was that FreeBSD's /bin/sh was the culprit, but I
> couldn't find any mention digging in the archive. However, I just
> checked on a FreeBSD 13 VM, and it does have the same problem (that the
> one-shot variable is not exported). I don't think that changes anything
> for your patch, but just reinforces this part:
>
> > This does *not* mean that we can freely start using the construct
> > once Ubuntu 20.04 is retired. But it does mean that we cannot use
> > the construct until Ubuntu 20.04 is fully retired from the machines
> > that matter.
And adding more confusion, which further reinforces the need to avoid
the construct and the usefulness of Eric's change [1], it sometimes
appears to function differently:
** dash 0.5.10.2-6 **
$ f() { echo $A; bash -c 'echo $A'; }
$ A=2
$ A=1 f
1
$ export A
$ f
2
2
$ A=1 f
1
1
1.- https://lore.kernel.org/git/2e1c8fc6-86f0-404f-bef6-9502aa0d31d0@xxxxxxxxx/T/#m3470fc6c1df59d29312bbe3de0444f1f608f3611
>
> since now we have one other instance.
>
> I thought it also had the issue that the variable would remain set in
> the caller after the function returned, but it does not seem to do so
> now (if it ever did).
>
> -Peff
