Re: [PATCH 0/6] test: make the test suite work with zsh

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

On Fri, Mar 31, 2023 at 6:04 PM Taylor Blau <me@ttaylorr.com> wrote:
>
> On Thu, Mar 30, 2023 at 08:19:08AM -0600, Felipe Contreras wrote:
> > > It is my impression, however, that zsh in its native mode is even
> > > further out and away, pushing it on the other side of the line of
> > > being reasonable to force our develoerps to adjust to.
> >
> > Just because it's your impression doesn't mean it's true.
>
> Sure, but zsh's incompatibility with bash is clear evidence that it is
> further out from the POSIX standard.

No, the POSIX standard is not whatever bash does; bash does many
things that are not part of POSIX, and it even has a POSIX mode
precisely because it does not follow it to a tee: `bash --posix`.

If `ksh` does something that bash does differently, is that evidence
that `ksh` is further out from the POSIX standard?

This argument does not make sense.

> But I think the argument is missing the point, anyway, which is that it's incompatible with POSIX.

So is bash.

All shells in the world are incompatible with the POSIX standard in
one way or another.

POSIX doesn't say anything about the $COLUMNS variable, and yet bash
sets it (and many other variables). Does that mean bash is
"non-POSIX"?

Of course not; POSIX doesn't say "thou shall not set the $COLUMNS
environment variable", so it's OK for bash to do that, it's still
compatible with posix (as long as you use `--posix`).

This's just not how standards work.

> Is it worth adapting our explicitly POSIX-compatible test suite to work
> with a non-POSIX shell? I think not.

All shells are non-POSIX.

-- 
Felipe Contreras