[Perl] Que faire contre ce « warning » ?

[Philippe Bruhat (BooK)]

On Sat, Jan 14, 2017 at 10:44:05AM +0000, Yon wrote:
> Si tu rajoutes:
> 
>     use diagnostics;
> 
> au début du fichier, tu obtiens plus de détails :
> 
>     (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
>     each(), or readdir() as a boolean value.  Each of these constructs
>     can return a value of "0"; that would make the conditional expression
>     false, which is probably not what you intended.  When using these
>     constructs in conditional expressions, test their values with the
>     defined operator.
> 

Sans modifier son programme, on peut aussi juste copier le message
(simulé ici avec `echo`) dans `splain`

    $ echo 'Value of <HANDLE> construct can be "0"; test with defined() at ./truc.pl line 11.' | splain
    Value of <HANDLE> construct can be "0"; test with defined() at ./truc.pl line
    	11 (#1)
        (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
        each(), or readdir() as a boolean value.  Each of these constructs
        can return a value of "0"; that would make the conditional expression
        false, which is probably not what you intended.  When using these
        constructs in conditional expressions, test their values with the
        defined operator.

Maintenant que j'ai lu la doc de splain/diagnostics.pm, je peux aussi vous
livrer cette petite perle qui s'y trouve:

    If you don't want to modify your source code, but still have on-the-fly
    warnings, do this:

         exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&-

    Nifty, eh?

-- 
 Philippe Bruhat (BooK)

 Eliminate a problem before it eliminates you!
                                    (Moral from Groo The Wanderer #65 (Epic))