get_post_types check for supporting title

[GaryJ]

In 3.2-beta2-18055, a print_r of:

get_post_types();

correctly returns:

Array ( [post] => post [page] => page [attachment] => attachment [revision] => revision [nav_menu_item] => nav_menu_item [surl] => surl [book] => book )

(Default post types, plus a couple of my extra ones).

However, a print_r of:

get_post_types( array( 'supports' => array( 'title' ) ) );

returns:

Array ( [attachment] => attachment [revision] => revision [nav_menu_item] => nav_menu_item )

instead of the ones that actually have support for the title feature.
The same result occurs when checking for editor support. I've tried my registered post types with and without title support, yet neither seem to appear when filtering by title support, not doe post or page, which I would also expect to be returned.

[greuben]

get_post_types( array( 'supports' => array( 'title' ) ) );

The default operator for get_post_types is 'AND' so it will match post types which only support title

Use 'OR' operator if you want all post types that support titles.

get_post_types( array( 'supports' => array( 'title' ) ), 'names', 'or' )

[GaryJ]

Replying to greuben:

Use 'OR' operator if you want all post types that support titles.

get_post_types( array( 'supports' => array( 'title' ) ), 'names', 'or' )

That results in:

Array
(
    [post] => post
    [page] => page
    [attachment] => attachment
    [revision] => revision
    [nav_menu_item] => nav_menu_item
    [surl] => surl
    [book] => book
)

My book CPT doesn't have support for title, yet is still included in the list.

@Nacin ​says that get_post_types() can't check for support, since it's an array, rather than a string/int/bool. The solution is to grab them all and loop through them and use post_type_supports().

Not a bug then - guess I was just trying to do something that hasn't been added to core, yet :-)

[scribu]

get_post_types( array( 'supports' => array( 'title' ) ), regardless of operator, will only match post types that only support 'title'.

Similarly, get_post_types( array( 'supports' => array( 'title', 'editor' ) ) will only match post types that only support 'title' and 'editor'. No more, no less.

Since there's no elegant way to define the operator between elements in the 'supports' array, you will just have to loop through all post types, using post_type_supports() to filter them.

[scribu]

Example:

$filtered = array();
foreach ( get_post_types() as $post_type ) {
  if ( post_type_supports( $post_type, 'title' ) ) {
    $filtered[] = $post_type;
  }
}

[GaryJ]

Noted, thanks scribu.