Re: M4sh tests 77 and 78 vs /bin/sh -> dash

[Bob Friesenhahn]

On Mon, 23 Mar 2020, Zack Weinberg wrote:
> Given that Debian is _deliberately_ configuring dash without LINENO
> support in order to work around configure scripts containing bashisms,
> I think we should make changes in this area cautiously and with a lot
> of public notice.  It's my personal opinion that we should push
> configure-script authors in the direction of not using bash
> extensions, maybe even at the expense of performance.

In my experience, bash is so popular as a command-line shell (and 
sometimes/often as a scripting shell) that configure-script authors do 
not know any better.  They are not aware that they are using 
bash-specific syntax since they often do not read documentation and 
just use what appears to work.  This applies to other shells as well, 
since it just depends on the shell that the developer used.

I do see Paul Eggert's follow on email which suggests that configure 
scripts should not inhibit the developer.

It is indeed true that some configure scripts are for convenience 
rather than portability, and it is ok to mix syntax in the script 
since the script does not fail unless syntax it does not understand is 
actually executed.  It might be ok to introduce a bash-specific shell 
function if it was only going to be executed by bash.

Bob
--
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt