Allow WP_Query to query by comment_count column of CPT/posts table

[ramon fincken]

In the current WP_Query, it is possible to order results by comment_count ASC/DESC.
But is it not possible to query the table based on this CPT/posts table column. Therefor it is impossible to (for example) query posts without any comment or posts having over 10 comments.

I propose a diff to use WP_Query in the following way (building on the syntax from meta_query and tax_query)

a) Easy call:
$args['comment_count'] = n; n >= 0

b) Extended call:
$args['comments']['count'] = n; n >= 0

Optional in this call:
$args['comments']['compare'] = Compare; Compare: =, !=, >, >=, <, <=

I will extend this ticket with a patch diff file (trunk) along with a testset (has-patch).

[ramon fincken]

Patch

[ramon fincken]

Unit test (props to robert-john van doesburg)

[ramon fincken]

Replying to SergeyBiryukov:
Thanks for adjusting, you beat me to it ;)

[boonebgorges]

I this this is a pretty good idea. A couple of comments (no pun intended):

• Let's not add two new params ('comment' and 'comment_count'). This seems unnecessary and confusing to me. I suggest having one: 'comment_count'. You can pass an array of 'count' and 'compare', or you can pass it a number, which gets parsed into array( 'count' => $number, 'compare' => '=' ).
• The unit tests look really comprehensive - thanks so much for that. Let's move them to tests/phpunit/tests/query/commentCount.php, since this is a new feature for WP_Query.
• In the unit tests: no need to do http_build_query() - just pass an array. No need to set dummy 'post_content' or 'post_type' on the factory posts - just use the defaults ($p1 = $this->factory->post->create(), with no arguments). Testing found_posts is not precise enough - please get the found post IDs and use assertEqualSets to compare with $this->q->posts. I recommend using the following arguments for WP_Query, to minimize overhead:

$this->q->query( array(
    'fields' => 'ids',
    'update_post_meta_cache' => false,
    'update_post_term_cache' => false,
    'comment_count' => array(
        'count' => 5,
        'compare' => '>',
    ),
) );

$expected = array( $p1, $p2 );
$this->assertEqualSets( $expected, $this->q->posts );

The functionality itself looks pretty nice, so with some of these changes I think we can put this in. Thanks for the contribution!

[ramon fincken]

Rewrote this on WordCamp Europe (Paris) to fit with WP 4.8

Uploading the patch and unit tests now

You can use it the integer way:

comment_count = INT

or array

comment_count = ARRAY ( value = INT [, compare = STRING ] )

for instance

<?php
                                'comment_count' => 1

or

<?php
                                'comment_count' => array(
                                        'value' => 6,
                                        'compare' => '<'
                                )

[ramon fincken]

Patch of class-wp-query.php

[ramon fincken]

New PHPUnit test file

[boonebgorges]

Thank you for circling back to this ticket, @ramon fincken. The patch, and especially the tests, are very good.

I've made some modifications in 28399.diff​:

• Added documentation and changed some formatting to match coding standards.
• In the tests, I've used a few convenience methods to simplify your code (you'd implemented your own versions of WP's wp_list_pluck() and assertEqualSets())
• Rearranged the way the SQL is assembled to be a bit more readable.

Please review the changes and make sure I've captured everything.

[ramon fincken]

I will check this tonight or tomorrow. Quick one yet: if we use prepare, why still use the intval on top?

[boonebgorges]

@ramon fincken It's probably redundant :)

[ramon fincken]

Yes, lets GO :)

The rewritten unit tests are much better readable. Thanks for that.

Do I need to do something at this point?

[DrewAPicture]

Replying to ramon fincken:

Do I need to do something at this point?

Nope :-) @boonebgorges will likely give everything another a once over and then commit if everything looks good.

[boonebgorges]

In 40978:

Introduce $comment_count param for WP_Query.

This parameter allows querying for posts with a specific value of
comment_count. It is also possible to query for posts that match
a comment_count comparison by passing an array with 'value' and
'compare' operators (eg array( 'compare' => '>', 'value' => 5 )).

Props ramon fincken.
Fixes #28399.