[wp-trac] [WordPress Trac] #53099: PHP warnings due to wp_check_term_meta_support_prefilter callback

[WordPress Trac]

#53099: PHP warnings due to wp_check_term_meta_support_prefilter callback
--------------------------+-----------------------------
 Reporter:  david.binda   |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  REST API      |    Version:  5.5
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 Following PHP warnings might be triggered in case the callback to
 `get_term_metadata` filter (inside the `get_metadata_raw` function)
 returns `false`. For instance, as the default
 `wp_check_term_meta_support_prefilter` callback does:


 {{{
 Warning: Invalid argument supplied for foreach() in wp-includes/rest-
 api/fields/class-wp-rest-meta-fields.php on line 97

 Warning: array_filter() expects parameter 1 to be array, bool given in wp-
 includes/rest-api/fields/class-wp-rest-meta-fields.php on line 293

 Warning: array_keys() expects parameter 1 to be array, null given in wp-
 includes/rest-api/fields/class-wp-rest-meta-fields.php on line 293

 Warning: array_map(): Expected parameter 2 to be an array, bool given in
 wp-includes/rest-api/fields/class-wp-rest-meta-fields.php on line 317

 Warning: array_unique() expects parameter 1 to be array, null given in wp-
 includes/rest-api/fields/class-wp-rest-meta-fields.php on line 317

 Warning: Invalid argument supplied for foreach() in wp-includes/rest-
 api/fields/class-wp-rest-meta-fields.php on line 319.
 }}}

 While the default callback returns bool (`false`) only on installations
 with old DB schema, pre term meta feature (and thus does not really
 produce the warnings in default state), the callback with it's `false`
 might serve as an example on how to short-circuit the `get_metadata_raw`
 function.

 Further, the `get_metadata_raw` function, or `get_metadata` which is
 calling that one, may also return `false` for other issues.

 That said, the boolean value returned by `get_metadata` function call is
 something what should, IMHO, be taken into consideration whenever working
 with the `get_metadata` function.

 However the methods in `WP_REST_Meta_Fields` class do not check the return
 value, and expect an array to be returned.

 The code, IMHO, should check for the value being an array before using it
 as an array in related cases.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/53099>
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