Subject: Re: [PATCH] t/t9902-completion.sh: backslashes in echo

From: Marcel Telka <[email-masked]>
Date: Thu, 23 May 2024 23:47:12 +0200

On Thu, May 23, 2024 at 05:06:00PM -0400, Eric Sunshine wrote:
> On Thu, May 23, 2024 at 4:32 PM Marcel Telka <[email-masked]> wrote:
> > On Thu, May 23, 2024 at 10:59:13AM -0700, Junio C Hamano wrote:
> > > Marcel Telka <[email-masked]> writes:
> > > > The usage of backslashes in echo is not portable.  Since some tests
> > > > tries to output strings containing '\b' it is safer to use printf
> > > > here.  The usage of printf instead of echo is also preferred by POSIX.
> > >
> > > This has cooked in 'next' for some time already, and I'll merge this
> > > down to 'master' anyway, but this being a script very much speicific
> > > to bash whose built-in echo we are using, the portability argument
> > > of "echo" made in the proposed log message does not quite apply to
> > > this patch.
> >
> > Could you please help me to understand how the bash is used to run the
> > script?
> >
> > $ head -n 1 t/t9902-completion.sh
> > #!/bin/sh
> 
> Looking a bit farther in t9902, you'll find:
> 
>     . ./lib-bash.sh
> 
> And if you look inside `lib-bash.sh`, you'll see that, if the
> currently-running shell is not Bash, it aborts the current script and
> re-runs it under Bash.

Thanks for the pointer!

Interesting.  I came to this issue because the test failed here due to
the echo.  So apparently the re-run under bash didn't happen here for
some reason or bash's echo behaved differently?  I need to dig into it
again to find what's going on.

> But Junio's point was that t9902 is dedicated to testing Bash-specific
> functionality, so the commit message's justification to avoid this
> non-POSIX behavior isn't necessarily a good justification for the
> change. (He wasn't saying that the change itself was unwelcome, just
> that the commit message wasn't convincing.)

Sure.  I understand the point.  I just had an impression that the test
is running under POSIX sh (/bin/sh), not bash, because it failed here
(see above).

OTOH, it seems that the fix is maybe not needed because it is solving a
non-problem.

Thank you.

-- 
+-------------------------------------------+
| Marcel Telka   e-mail:   [email-masked]  |
|                homepage: http://telka.sk/ |
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