[wp-trac] [WordPress Trac] #63902: wp_get_post_autosave() uses a non-limited SQL query

[WordPress Trac]

#63902: wp_get_post_autosave() uses a non-limited SQL query
--------------------------+-----------------------------
 Reporter:  dd32          |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Query         |    Version:  6.8
 Severity:  minor         |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 In [59715] via #62658 wp_get_post_autosave() was switched from a raw SQL
 (with a `LIMIT 1`) to a cached WP_Query instance with `posts_per_page=1`

 However, as `name=...` is specified, WP_Query doesn't apply the
 posts_per_page limitation.

 This is because a `name=...` sets `is_singular`, which then causes the
 post pagination to be skipped:
 https://core.trac.wordpress.org/browser/trunk/src/wp-includes/class-wp-
 query.php?rev=60697&marks=2797-2798,2811#L2797


 ''This is not a problem at present, as the `name` being queried
 '''should''' only have a singular result.''

 For example ''(Returns false, as there's no autosave, but it's the query
 we're interested in, noting the lack of limit)''
 {{{
 wp> wp_get_post_autosave( 123 );
 bool(false)

 wp> $wpdb->last_query;
 SELECT   wp_posts.ID
 FROM wp_posts
 WHERE 1=1  AND wp_posts.post_name = '123-autosave-v1' AND
 wp_posts.post_parent = 123  AND wp_posts.post_type = 'revision' AND
 ((wp_posts.post_status = 'inherit'))

 ORDER BY wp_posts.post_date DESC
 }}}

 This could have other side effects for plugin code, where instead of using
 the core `wp_get_post_revisions()` a WP_Query similar to
 `post_type=revision&post_name=$ID-revision-v1&posts_per_page=1&order=DESC`
 is made, expecting a singular result but getting all revisions. (Querying
 by `name=...` is not expected here, and should be
 `post_type=revision&post_parent=$ID`, but I can imagine a world where
 someone queries by name to avoid image attachments or something that
 wouldn't ever be returned anyway)


 Two options as I see it:
 1. LIMIT 1 for all singular queries (Although, as noted, revisions break
 the notion of a singular post_name per post_type)
 2. Respect the posts_per_page given for singular queries, if provided.
 This may mean having to set a default of `1` when `name` is set.

 ''Thanks to @vortfu for raising this, fyi @spacedmonkey since you were the
 committer of above''

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/63902>
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