PHP 7.2 warning - Parameter must be an array or an object that implements Countable in /wp-includes/class-wp-query.php on line 3035

[lisota]

Upgrading to PHP 7.2 results in the following PHP warning from class-wp-query.php

PHP Warning: count(): Parameter must be an array or an object that implements Countable in /wp-includes/class-wp-query.php on line 3035

[tw2113]

For what it's worth, the line in question is

$this->found_posts = count( $this->posts ); inside function set_found_posts()

[johnbillion]

Thanks for the report.

• Are you able to determine the source of the error (ie. where the query is called from)?
• Does it still occur with all your plugins deactivated?
• What's the value of $this->posts at this point?

Thanks

[ayeshrajans]

It looks like the $this->posts variable was left default null, causing the warning when called with count().
Attached a patch that might solve it, but we should really be waiting for the reporter's information. A backtrace can explain a lot.

[ayeshrajans]

Tests: ​https://travis-ci.org/Ayesh/wordpress-develop/builds/314423062

[ayeshrajans]

Above travis URL is wrong. Please see this: ​https://travis-ci.org/Ayesh/wordpress-develop/builds/314425033

[dd32]

After looking over this, I can only assume that there's a caching plugin in play which has set $this->request to null or '' which causes $this->posts to be set to the same thing instead of an array as expected.

The correct fix here is probably to ensure that $this->posts is always set to an array, even when $this->request is emptied out.

[SergeyBiryukov]

Replying to dd32:

The correct fix here is probably to ensure that $this->posts is always set to an array, even when $this->request is emptied out.

The comment in WP_Query::set_found_posts()​ specifically allows for $this->posts to not be an array though:

// Bail if posts is an empty array. Continue if posts is an empty string,
// null, or false to accommodate caching plugins that fill posts later.

I think we should just check if is_array() before calling count().

[lisota]

Let me see if I can grab a backtrace. I rolled out PHP 7.2 on our production site, and experienced a number of errors related to 7.2, including this one, and promptly rolled back.

[dd32]

Bumping to 4.9.3 due to 4.9.2s release

[josephscott]

I agree with doing an array check first, could be something very simple:

            $this->found_posts = 0;
            if ( is_array( $this->posts ) ) {
                $this->found_posts = count( $this->posts );
            }

[janak007]

Added array check and return the post counts

[janak007]

Added array check and return the post counts

[jorbin]

In 42581:

Query: Fix warning on counting non countable

Adds tests to continue the behavior for both null and strings.

See ​https://wiki.php.net/rfc/counting_non_countables for information on the PHP change.

Fixes #42860.
Props janak007 and ayeshrajans for initial patches.

[dd32]

In 42585:

Tests: Skip newly added tests from [42581] on PHP 5.2 as they require ReflectionMethod.

See #42860.

[SergeyBiryukov]

[42581] doesn't look complete to me. Per comment:7, an empty string or false should be treated the same as null.

[SergeyBiryukov]

To clarify a bit, [42581] does keep the previous behavior, I'm just not sure it's correct. If $this->posts is false or an empty string, I'd expect found_posts to be 0.

[jorbin]

Replying to SergeyBiryukov:

[42581] doesn't look complete to me. Per comment:7, an empty string or false should be treated the same as null.

That's not how count works. It would be a breaking change to set it as 0 in those instances.

From ​http://php.net/manual/en/function.count.php#refsect1-function.count-returnvalues

Returns the number of elements in array_or_countable. When the parameter is neither an array nor an object with implemented Countable interface, 1 will be returned. There is one exception, if array_or_countable is NULL, 0 will be returned.

[jorbin]

The above patch reorganizes the tests to include an empty string and false

[SergeyBiryukov]

Replying to jorbin:

It would be a breaking change to set it as 0 in those instances.

Right, on second thought I agree breaking back compat is not worth it. Let's add 42860.diff​ then.

[jorbin]

In 42594:

Query: Improve tests for set_found_posts dealing with non arrays

Use a data provider and include tests for false and ''.

Previous: [42581] [42585]

See #42860

[jorbin]

In 42597:

Query: Fix warning on counting non countable

Merges [42581], [42585], and [42594] to the 4.9 branch.

Adds tests to continue the behavior for both null and strings. Skip the tests on PHP 5.2 as they require ReflectionMethod.

See ​https://wiki.php.net/rfc/counting_non_countables for information on the PHP change.

Fixes #42860.
Props dd32 for test skipping and janak007 and ayeshrajans for initial patches.

[leemon]

Is this really fixed? I'm still getting this warning in sites under PHP 7.2

[jonasrafael]

I have the same problem.

PHP message: PHP Warning: count(): Parameter must be an array or an object that implements Countable in /wp-includes/post-template.php on line 284

Nginx
PHP Version 7.2.7-1+ubuntu16.04.1+deb.sury.org+1