Interactivity API: Some property access does not work well in server directives

[jonsurrell]

The Interactivity API uses .-delimited paths to describe where data lives in interactivity state and context.

In my testing, associative and numeric arrays are well handled in PHP. PHP objects can be serialized in state and used by the client as JavaScript objects, but directive processing on the server throws an error. For example:

<?php
$obj = new stdClass();
$obj->prop = 'property';
wp_interactivity_state('ns', array(
        'obj' => $obj,
));
?>
<div data-wp-interactive="ns">
        <div data-wp-text="state.obj.prop"></div>
</div>

Throws:

Fatal error: Uncaught Error: Cannot use object of type stdClass as array in /var/www/html/wp-includes/interactivity-api/class-wp-interactivity-api.php:397
Stack trace:
#0 /var/www/html/wp-includes/interactivity-api/class-wp-interactivity-api.php(787): WP_Interactivity_API->evaluate('state.obj.prop', 'ns', false)
#1 /var/www/html/wp-includes/interactivity-api/class-wp-interactivity-api.php(351): WP_Interactivity_API->data_wp_text_processor(Object(WP_Interactivity_API_Directives_Processor), 'enter', Array, Array, Array)
#2 /var/www/html/wp-includes/interactivity-api/class-wp-interactivity-api.php(229): WP_Interactivity_API->process_directives_args('process_directives('apply_filters('render()
#9 /var/www/html/wp-includes/blocks.php(1743): render_block(Array)
#10 /var/www/html/wp-includes/class-wp-hook.php(324): do_blocks('

Arrays and objects are accessed without issue in JavaScript. It would be nice if property access in PHP would access object properties or associative array values correctly.

[jonsurrell]

​wpdb::get_results by default returns an array (the rows) of objects by default. That's one example where this type of property access would be handy.

Using the $wpdb->get_results( …, ARRAY_A ) does provide associative arrays for each row which can be accessed from the Interactivity API without issues.

[gziolo]

Would it be possible to automatically cast array to object or the other way around so directive processing can always work with one type of data mirroring how JS works? For example enconding and decoding as JSON could do the trick.

[jonsurrell]

Would it be possible to automatically cast array to object or the other way

I had an implementation that seemed to work that checked is_array() and used either $arr[$prop] or $obj->$prop access. It seemed to work well and I think that should be sufficient.

Another solution would be ​get_object_vars(), but I think we'd still have a conditional check and would be creating full arrays we don't really need.

Trac ticket: https://core.trac.wordpress.org/ticket/61039

Trac ticket: https://core.trac.wordpress.org/ticket/61039

Updates ​https://github.com/WordPress/wordpress-develop/pull/6581 with an unit test.

It looks good to me, too! Nice work 👍

@cbravobernal, is this patch ready to land? ​https://github.com/WordPress/wordpress-develop/pull/6672#discussion_r1622282621 – any actions to take here?

@cbravobernal​[[Image(chrome-extension://hgomfjikakokcbkjlfgodhklifiplmpg/images/wp-logo.png)]], is this patch ready to land? ​#6672 (comment) – any actions to take here?

I removed the bool type and added #[\ReturnTypeWillChange] at the beginning of the function like you mentioned to keep consistency with other parts of the code. Let's see the tests.

All green so ready to land!

[gziolo]

In 58320:

Interactivity API: Some property access does not work well in server directives

Ensures property access in PHP works for object properties or associative array values correctly when processing Interactivity API directives.

Props narenin, cbravobernal, jonsurrell, gziolo, czapla.
Fixes #61039.

Committed with https://core.trac.wordpress.org/changeset/58320.

The work here was landed as part of https://core.trac.wordpress.org/changeset/58320. This PR can be closed. Thanks @narenin!

@sirreal Thanks for the update. I have closed the PR.