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List:       php-general
Subject:    Re: [PHP] Redundant isset() check?
From:       Dotan Cohen <dotancohen () gmail ! com>
Date:       2014-11-04 12:32:06
Message-ID: CAKDXFkN=F=cp4AsnihKLcACYOyRVTzWet2=JcrFsRSQZJ-p9VA () mail ! gmail ! com
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I take that back. I do think that || is the correct behaviour. If
$_SERVER['DOCUMENT_ROOT'] is not set, then short-circuit and perform
the TRUE portion of the if clause. If it is set, then check if
$connection_details[$_SERVER['DOCUMENT_ROOT']] is set.

I suppose that we could use DeMorgan's law to negate the negations,
but then the code is less readable and clear.


On Tue, Nov 4, 2014 at 2:07 PM, Dotan Cohen <dotancohen@gmail.com> wrote:
> On Tue, Nov 4, 2014 at 1:34 PM, Ashley Sheridan
> <ash@ashleysheridan.co.uk> wrote:
> > You nearly had it, it should be something like:
> > 
> > if ( !isset($_SERVER['DOCUMENT_ROOT']) &&
> > !isset($connection_details[$_SERVER['DOCUMENT_ROOT']]) ) {
> > 
> > The reason for && and not || is that an kr can still fail on \
> > $_SERVER'[DOCUMENT_ROOT'] being set and still try to use it in the second part of \
> > the if(). The and will only return true if both are set. 
> > have you tested with warnings turned on (as they should be on every development \
> > environment) and tested with a non-existent $_SERVER array element? 
> 
> Thank you. At the point as which I asked the development code is not
> yet written. On other projects I have done the initial (possibly
> redundant) isset() check properly using &&, but for this mailing list
> question I accidentally used ||. I agree, proper unit testing
> discipline would have caught that!
> 
> That you for letting me know that the check is not redundant. I do
> prefer to have warnings turned on but not displayed to users on
> production systems, of course!
> 
> --
> Dotan Cohen
> 
> http://gibberish.co.il
> http://what-is-what.com



-- 
Dotan Cohen

http://gibberish.co.il
http://what-is-what.com

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