Understanding PHP Strict - why should I care?

Question

In a recent question I posted I describe how I developed a site on my local server and everything was working fine. Then after deploying it live I was getting errors because of the use of undefined variables. Mainly due to situations like the following...

if($var!=""){...}

I know I should use PHP strict and fix all of the errors based on the responses I got on my last question.

Now I want to know... why? What vulnerabilities may be created by leaving such code? I want to be able to justify to others why the errors need to be fixed.

You'll find a lot of helpful reasons by going through similar questions/answers http://stackoverflow.com/search?q=%5Bphp%5D+strict+errors — Mike B, Oct 06 '11 at 21:15
Using an undefined variable is an `E_NOTICE`, not `E_STRICT`, right? Strict messages are similar to notices, but tend to be more for things that will change in the future, or are more "nitpicky" than notices. — John Flatness, Oct 06 '11 at 21:15

score 7 · Accepted Answer · answered Oct 06 '11 at 21:10

7

The purpose of E_STRICT messages is:

to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code.

^{Source: Error Handling Constants}

answered Oct 06 '11 at 21:10

salathe

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score 1 · Answer 2 · edited Apr 22 '20 at 19:36

1

In this case, it's because the behaviour won't be predictable.

If your variable is not defined, your condition could be true or wrong, randomly.

edited Apr 22 '20 at 19:36

Peter Mortensen

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answered Oct 06 '11 at 21:11

Imad Moqaddem

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Actually it's predictable. But coders are still supposed to define variables by giving them values. http://www.php.net/manual/en/language.variables.basics.php – OpenGG Oct 06 '11 at 21:20

score 0 · Answer 3 · answered Apr 22 '20 at 19:43

0

Reminder isset function accept multiple variable while empty does not.

if(isset($var_1, $var_2) && !empty($var_1) && !empty($var_2)){
  // code
}

answered Apr 22 '20 at 19:43

Tesla

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score 0 · Answer 4 · answered Oct 06 '11 at 21:37

0

if (isset($var) and $var != "")

or:

if(strlen($var) > 0)

answered Oct 06 '11 at 21:37

radeklos

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Understanding PHP Strict - why should I care?

4 Answers4