[wp-trac] [WordPress Trac] #24142: Zero value for posts_per_page value in wp_query custom instance and for 'Blog pages show at most' option

[WordPress Trac]

#24142: Zero value for posts_per_page value in wp_query custom instance and for
'Blog pages show at most' option
------------------------------------------+-----------------------------
 Reporter:  alexvorn2                     |       Owner:
     Type:  defect (bug)                  |      Status:  reopened
 Priority:  normal                        |   Milestone:  Future Release
Component:  Query                         |     Version:
 Severity:  normal                        |  Resolution:
 Keywords:  needs-patch needs-unit-tests  |     Focuses:
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Comment (by birgire):

 I agree that this is a strange behavior.

 To better understand it, we can map it out for version 4.8.2:


 {{{
 value           posts_per_page  showposts       posts_per_archive_page
 posts_per_rss
 --------------------------------------------------------------------------------------
 null    |       default         default         default
 default
 ''      |       default         default         default
 default
 0       |       default         default         default
 default
 '0'     |       default         default         default
 default
 true    |       none            1               none                    1
 false   |       default         default         default
 default
 10      |       10              10              10                      10
 '10'    |       10              10              10                      10
 'string'|       1               1               default                 1
 array() |       default         default         1
 default
 -1      |       none            none            none
 none
 -2      |       2               2               2                       2

 }}}

 where default means the stored option's value.

 So there are some strange inconsistencies, e.g. the {{{true}}} row ;-)

 The scope? of the ticket seems to be adjust the the {{{0}}} and {{{'0'}}}
 rows to:


 {{{
 value           posts_per_page  showposts       posts_per_archive_page
 posts_per_rss
 -------------------------------------------------------------------------------
 0       |       0               0               0                       0
 '0'     |       0               0               0                       0

 }}}


 I think these two row cases, should be the same as returning an empty
 array from
 the {{{posts_pre_query}}} filter,

 https://core.trac.wordpress.org/browser/tags/4.8.2/src/wp-includes/class-
 wp-query.php#L2781

 so we don't have to run those db queries. Like using {{{$this->posts =
 array()}}}.

 We would need to check for e.g.

 {{{
 if( isset( $q['posts_per_page'] ) && ( 0 === $q['posts_per_page'] || '0'
 === $q['posts_per_page'] ) ) {

 }}}

 and something simlar for the other query variables.

 We would also have to adjust this part accordingly:

 https://core.trac.wordpress.org/browser/tags/4.8.2/src/wp-includes/class-
 wp-query.php#L1785-L1798

 i.e.

 {{{
 $q['posts_per_page'] = (int) $q['posts_per_page'];

 if ( $q['posts_per_page'] < -1 )
         $q['posts_per_page'] = abs($q['posts_per_page']);
 elseif ( $q['posts_per_page'] == 0 )
         $q['posts_per_page'] = 1;

 }}}


 The e.g. case of {{{'showposts' => 'string'}}} is a little bit tricky here
 for detection, because of the previous {{{$q['showposts'] = (int)
 $q['showposts'];}}}

 Before writing any patches I think we should consider what the scope of
 this ticket should be,
 i.e. should it be to only adjust the {{{0}}} and {{{'0'}}} rows or if
 should it be also touch the {{{true, false, 'string', array(), ...}}}
 rows?

 Hope this helps anyone that's going to tackle this problem.

--
Ticket URL: <https://core.trac.wordpress.org/ticket/24142#comment:9>
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