Developer API troubleshooting

Last updated Oct 3, 20264 min read

First step for any problem: turn on WP_DEBUG and look at WPM Fields › Settings › Health. Bad object arguments and refused values raise _doing_it_wrong() notices, and runtime failures are logged there instead of breaking the page.

`wpmcf_get_field()` returns `null` or the default

Check	Fix
Wrong keys	Use the Key of the group and field from the builder (not labels). Keys are lower-cased.
Field is inside a Group or Repeater	Read the top-level field and add `'path' => 'sub_key'` or `'path' => '0.name'`. Sub-fields have no column of their own.
No current post	Outside the loop pass an ID: `wpmcf_get_field( 'g', 'f', get_queried_object_id() )`.
User, term or comment	Pass `"user_3"`, `"term_5"`, `"comment_7"` or the object. There is no "current" user/term/comment. See Object references.
Group is not attached to that object type	Check the group's location rules.
Plain numeric ID for a user	A bare `3` means post 3. Use `"user_3"` or `'context' => 'user'`.
`context` conflicts with the reference	An explicit `context` wins over `"user_3"`.
Value was never saved	The default is returned for `NULL` only. An empty string that was saved is returned as `''`.
Values from an import/other plugin	If written to post meta they are not in the table. See the meta bridge in Field groups.

`wpmcf_the_field()` prints nothing

The value is empty (nothing is ever printed for empty values).
It is a Password field (never printed). See Password helpers and security.
A Group, or any array with format other than auto: use a path, or auto for Repeaters.
The object reference is invalid (a notice appears under WP_DEBUG).

`wpmcf_update_field()` returns `false`

Cause	Check
Unknown group or field key	Typos; the field must be top-level and have a column (not a Tab or Accordion).
Object does not exist	The post, user, term or comment ID is wrong.
Invalid reference	See Object references.
The field type refused the value	A `_doing_it_wrong()` notice states the reason (for example a password over 128 bytes or outside min/max length).
Field type not available	A Pro type without an active license cannot be written.
Database error	Look in Settings › Health.

It returns true but the field reads back empty when the type drops values it cannot accept: a select choice that does not exist, an invalid URL, a non-numeric number. Read the value back and compare. See Writing values.

A value is saved but disappears or changes

Text fields strip HTML tags on save (<b> is removed); use a Textarea/WYSIWYG field for markup.
A WYSIWYG field removes scripts and unsafe markup.
The next edit screen save overwrites the values of fields on that screen.

A shortcode prints nothing

See the table in Shortcodes. The most common cause is the visibility rule: private posts, drafts, password-protected posts, other users' fields and options values in a contributor's content are hidden on purpose.

`[wpmcf_global]` / `wpmcf_the_global()`

Expressions and default work like in wpmcf_get_global(). Older builds printed {{ ... }} literally and ignored default: update the plugin.
Prints nothing for a password variable: by design.

Block shows nothing

See Blocks and Block Bindings. Set a fallback on the WPM Field block to confirm the block renders at all.

`wpmcf_query` is ignored

Symptom	Cause
Every post is returned	You used `get_posts()` (it suppresses filters). Use `wpmcf_query_posts()`, `WP_Query`, or `'suppress_filters' => false`.
No posts at all	An argument is invalid (typo in the reference, unknown operator, group not attached to posts). Enable `WP_DEBUG` to see the `_doing_it_wrong()` message.
`?orderby=wpmcf:...` in the URL does nothing	By design for the main query. Use the `wpmcf/query/public_orderby` filter.
`compare => '='` on a number cast to `CHAR` finds nothing	Number columns cast to `CHAR` give `'20.000000'`. Drop the `type`.
Posts without a value missing from `!=`	Negations on empty values do not match `NULL`; add a `NOT EXISTS` clause with `relation => 'OR'`.

REST requests

Response	Meaning
No `wpmcf` in the response	The group's Show in the REST API is off, or no rule says Post type is equal to that type.
`401 rest_cannot_edit`	Not logged in (or the application password is wrong).
`403 rest_cannot_edit`	The user cannot edit that post (a subscriber, or a contributor on someone else's post).
`400 wpmcf_rest_unknown_group`	Wrong key, REST off, or the group's location does not match this post.
`400 wpmcf_rest_unknown_field`	Wrong field key, or the field has no column.
`400 wpmcf_rest_invalid_value`	`wpmcf` is not an object of objects, or the type reported an error.
`wpmcf` is `[]` for a protected post	Password-protected posts hide values in the view context.
Post created although you got `400`	Core inserts the post before the field values are processed. See REST API.

The wpmcf/v1 routes answer 401 logged out and 403 without manage_options: they are for the admin UI, not for integrations.

Still stuck

Check the item against the function's own page: Reading, Writing, References, Output, Function reference. For hooks and expressions see Variables and hooks.

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Developer API troubleshooting

wpmcf_get_field() returns null or the default

wpmcf_the_field() prints nothing

wpmcf_update_field() returns false