Re: [Help-bash] Awkward behavior of empty arrays

[Chet Ramey]

On 9/7/17 8:18 AM, Greg Wooledge wrote:
> On Thu, Sep 07, 2017 at 11:31:01AM +0200, Cristian Zoicas wrote:
>>> Hm, interesting.  I think your whole message below can be rephrased as: 
>>> empty arrays don't work with set -u.  Is that right?
>>
>> right...
> 
> You know, I'd been taking this assertion on faith, but after testing
> it, I just don't see any evidence that it's true.

It changed in bash-4.4:

3.  New Features in Bash

a.  Using address@hidden or ${a[*]} with an array without any assigned elements 
when
    the nounset option is enabled no longer throws an unbound variable error.

Originally, the nounset option worked on everything: variables, individual
positional parameters ($1), the set of positional parameters ($@), arrays,
special parameters that haven't gotten a value ($! when there haven't been
any asynchronous processes), etc. Posix decided on the special handling of
$@ in 2009, though treating $@ as a non-fatal error when there are no
positional parameters and nounset is enabled was not historical practice.
I changed the handling of address@hidden when A has no assigned elements to 
match
that behavior.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/