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Warning: count(): Parameter must be an array or an object that implements Countable in...

I'm getting the above error on the following line.

if (0 >= count($this->xprop))

Can someone help me understand this? I'm fairly new to PHP. The issue is obviously with $this->xprop not being an array. It wasn't an issue before I upgraded to PHP 7.2. How can I get around this? Are code with warnings still being executed or is this going to cause execution to fail?

I've tried to follow the second answer on here with no luck. The accepted answer is not acceptable to me as it is more of a hack.

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    Rather than attempt to ignore the error, you should try to fix the problem given that it will most likely effect the running of your app. Commented Aug 21, 2018 at 23:29
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    See the migration guide and do a find on Warn when counting non-countable types Commented Aug 21, 2018 at 23:31
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    Good luck, that may not be as simple as it sounds :) WP Code is the nastiest code I have seen in my life Commented Aug 21, 2018 at 23:39
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    Can you advise what $this is? Just because it's in WP doesn't mean it's "WordPress code". Better would be to edit the answer and include the results of var_dump($this->xprop). Not to dispute RiggsFolly - major props to him - but I actually doubt this is WP core code.... Commented Aug 22, 2018 at 0:29
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    If it's a plugin, get in touch with the maintainers and / or file a bug report Commented Aug 22, 2018 at 0:39

4 Answers 4

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PHP 7.2 throws an error when trying to count, or get the size of, a variable that isn't set. In previous versions, authors would shortcut checking to see if the variable was set by just counting (or sizeof'ing) it, and getting "0" on an unset variable.

The solution is to check to see if it's set before counting it:

if (isset($this->xprop) && count($this->xprop) == 0)

Your example above is actually negative logic, and is a pretty strange way of stating "if the size of this array is zero, or less than zero" (which is impossible). So, following your example above, the PHP 7.2 compliant version would be to use empty:

if (empty($this->xprop))

... because a variable can be set ($xprop = array()) but still be empty.

Sorry if this is a bit unclear; it's late here!

Foul

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5 Comments

count($this->xprop) > 0 <- you've reversed the original logic here. Probably not what you want to do
Nope -- look at it again. :) The logic in the OP is screwy. "If zero is greater than or equal to the count of the variable"... more clearly stated, "if the count of the variable is equal to or less than zero", or better, "if the count of the variable is zero" (because it can't be less than zero).
0 >= n is equivalent to n <= 0 which is quite different to what's in your answer. empty() is a good call though
Oh I see, you're talking about my example with the isset. Yes, that logic is incorrect; I just wanted to demonstrate that you need to check to see if the variable is set before you attempt to count it. The second example, if (empty($this->xprop)), is correct and maintains the intended logic.
@FoulFoot Thank you for the answer and explanation. That worked beautifully.
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the problem is caused because of the PHP version.

In PHP 7.2 , the count() method does not support null as argument .

Example :

in PHP 5.6.x :

echo count(null); // this show 0

in PHP 7.2.x :

echo count(null); // count(): Parameter must be an array or an object that implements Countable

So you should verify if the variable is not null

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1

if you are using php7.3 or above you can use is_countable before the count

rfc/counting_non_countables

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1

There are some ways, but I like the new ??-operator, because it is short:

$null = null;

echo count($null);                           // Warning: count(): Parameter must be an array or an object that implements Countable
echo is_countable($null) ? count($null) : 0; // => 0
echo count((array)$null);                    // => 0
echo count($null ?? []);                     // => 0
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