PHP deprecation: undefined `$template->media` property access during template save

[bph]

What

includes/create-theme/theme-templates.php:233 reads $template->media without checking whether the property exists on the WP_Block_Template object:

// Write the media assets if there are any
if ( $template->media ) {
    CBT_Theme_Media::add_media_to_local( $template->media );
}

The media property is only attached by prepare_template_for_export() on code paths where there is image media to localize. On every other path the property is simply absent — and this line reads it unconditionally.

When it triggers

• PHP 8.2+ emits a Deprecated: Creation of dynamic property / Undefined property notice on every save where a template has no media to localize (i.e. most saves).
• PHP 9 will turn this into a warning.
• It does not currently break anything functionally — it just leaks notices into the PHP error log.

How it was discovered

Surfaced by a strict error handler in the new PHPUnit regression test added in #833. That test was narrowed to only catch the processOnlySavedTemplates regression so it does not fail on this unrelated pre-existing issue.

Suggested fix

One-line change at theme-templates.php:233:

- if ( $template->media ) {
+ if ( ! empty( $template->media ) ) {

! empty() returns false for both undefined and falsy values, so the existing behavior is preserved for the cases where the property is set.

Notes

• Out of scope for Refactor: Extract CBT_Theme_Save service from rest_save_theme #833 (CBT_Theme_Save extraction) per that issue's scope guarantees.
• The same pattern (defensive ! empty()) is worth a quick scan across the file for sibling property reads on $template — there may be similar reads elsewhere.