Re: issue with [[ -v A[\$k] ]]

[alex xmb ratchev]

heya ..

On Sun, May 21, 2023, 23:36 Kerin Millar <kfm@plushkava.net> wrote:

> On Sun, 21 May 2023 22:35:03 +0200
> alex xmb ratchev <fxmbsw7@gmail.com> wrote:
>
> > i made some simple dup file by checksum remover
> > however the [[ -v assoc[\$var] didnt work
> >
> > maybe due to your announced changes
> > i dunno
> > i cant track or much understand that english
> >
> > to pre explain my code
> > a is arr with files ( non dirs ) by find "$@"
> > h is the same file mapping but in hashes
> > first a is first h .. and so on
> > if #a != #h exit with err ( i fast exec i dont care )
> >
> > then interate from keys h ( or a , same .. )
> > and in there i like used to , did [[ -v assoc[\$key] ]]
> > but to my surprise it didnt work
> > .. i have declare -n for short"
> > but after z=$key to plain var , it still didnt work
> > after removing the backslash before $key it worked
> > i figured i d try ${key@Q} as key but it also didnt work
> >
> > so ..
> > [[ -v assoc[$key] ]] .. without \ works
> > rest not anymore ?
> >
> > whats the non eval version of assoc [[ -v
> > is it already
>
> One way is to write [[ -v 'assoc[$key]' ]], which, if I recall correctly,
> should work in both 5.2 and prior releases.
>
> Generally speaking, bash is afflicted by a range of defects concerning the
> expansion of associative array subscripts. Every once in a while, certain
> behaviours end up being (arguably) improved in a manner that is difficult
> to reason with other than through trial and error. Meanwhile, workarounds
> previously known to be 'good' are rendered ineffective, thereby breaking
> existing scripts. The release notes for 5.2 allude to the latest round of
> attempts:
>

yea many scripts i wrote ( in total ) and many old scripts nowork at all
but really i dont care .. for me newest version and etc
no hpux or aix

i can only appell to upstream to fix it
.. a major code functionality ( along many others thelike )

"The shell attempts to do a much better job of parsing and expanding array
> subscripts only once; this has visible effects in the `unset' builtin, word
> expansions, conditional commands, and other builtins that can assign
> variable values as a side effect."
>

i tried on deb 5.2.15 release

btw wasnt it 'in interactive extglob is enabled'
not for this bash deb has ..

As Greg mentioned in his reply, test -v is commonly misapplied and the way
> in which subscripts are treated in the arithmetic context has been
> significantly affected (though that is not the exact use case that you
> raised). At this juncture, I can only agree with him; these features of the
> language are unstable. Moreover, the workarounds that are effective today
> may not be effective tomorrow. All in all, the avoidance of these features
> should result in scripts that are markedly more likely to be
> forward-compatible.
>

when its clear that upstream wont fix it , ill do the workaround
.. yet its not so clear to me :))

-- 
> Kerin Millar
>

greets .. /)

>