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

[alex xmb ratchev]

heya ..

On Sun, May 21, 2023, 22:48 Greg Wooledge <greg@wooledge.org> wrote:

> On Sun, May 21, 2023 at 10:35:03PM +0200, alex xmb ratchev wrote:
> > q : what bash code to write to have random input as secure keys ?
>
> 1) I would avoid using the -v operator, period.  I've seen nothing but
>    bug reports coming from people who try to use it.  There's even a
>    BashPitfall for it <https://mywiki.wooledge.org/BashPitfalls#pf61>.
>    Your backslash workaround might be OK, in some versions of bash,
>    but I wouldn't trust it, especially given how many workarounds
>    were broken by bash 5.2.
>

this is a headpaining workaround ..
i rather ( really ) need .. hm .. -v in [[ working
.. by an english description maybe ..

   Instead of using -v to test for existence of a key, use a non-empty
>    value.  Then actually EXPAND the array element, and see if you get
>    a non-empty string.
>
>    hash[$key]=1
>
>    if [[ ${hash[$key]} ]]; then     # BUT!  See part 2.
>        echo "key exists"
>    else
>        echo "key does not exist"
>    fi
>
>
> 2) To allow arbitrary keys, including the empty string, use the "x hack".
>
>    hash[x$key]=1
>
>    if [[ ${hash[x$key]} ]]; then
>        echo "key exists"
>    else
>        echo "key does not exist"
>    fi
>

i , to use this , really gotta benchmark first
but thats way later , ...
u may remember on irc , i wasnt using old code such as this

its funny how portable this looks tho ..
the epic x

3) Don't use an associative array expansion inside an arithmetic context,
>    because of <https://mywiki.wooledge.org/BashPitfalls#pf62>.  This may
>    not apply to your use of the associative array as a set, but I'll
>    just mention it here for posterity.
>

its not my case :)

Part 1 means you can't use set -u.  So don't use set -u.  Simple!
>

this is also not my case , i never set -e or -u ..

hope my texts werent so depressive
i m abit working on it .. slowly ..

>