[wp-trac] [WordPress Trac] #28099: Empty array passed to WP_Query post__in returns posts

[WordPress Trac]

#28099: Empty array passed to WP_Query post__in returns posts
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 Reporter:  danielbachhuber          |       Owner:  wonderboymusic
     Type:  defect (bug)             |      Status:  reopened
 Priority:  normal                   |   Milestone:  Awaiting Review
Component:  Query                    |     Version:
 Severity:  normal                   |  Resolution:
 Keywords:  2nd-opinion needs-patch  |     Focuses:
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Changes (by azaozz):

 * keywords:  has-patch => 2nd-opinion needs-patch


Comment:

 Replying to [comment:39 pikamander2]:
 > If there's any way to rip off the band-aid and make passing 0 actually
 return 0 posts, I think that would be the best way forward.
 > ...
 > 1. Temporarily throw a deprecation warning in an upcoming release when 0
 is passed...
 >
 > 2. In a release sometime after that, remove the deprecation warning and
 make 0 actually return 0 posts.

 I tend to agree with @dd32's assessment from 13 years ago:
 https://core.trac.wordpress.org/ticket/12212#comment:10. The fact that
 non-existing `post__in` is filled with an empty array is a quirk in
 WP_Query.

 However what would be the purpose to query posts when you want to not find
 any? Its the same as driving to the grocery store with a shopping list
 with zero items on it, then buying nothing and returning empty handed :)

 > the post__in array(0) hack no longer works, but rather shows all posts
 just like the empty array

 Is there a better way to do what you need to do without having to use "a
 hack" and run a query for zero items?

 Thinking this can be seen as a regression of "doing-it-wrong" (unintended)
 use. Seems the "post__in array(0)" hack will have to be restored. However
 thinking a "Doing it wrong" would also be needed there.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/28099#comment:41>
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