resolve_block_template( string $template_type, string[] $template_hierarchy, string $fallback_template ): WP_Block_Template|null

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$template_typestring

The current template type.

$template_hierarchystring[]

The current template hierarchy, ordered by priority.

$fallback_templatestring

A PHP fallback template to use if no matching block template is found.

Return value

WP_Block_Template|null

template A template object, or null if none could be found.

Performance profile

How much work a call to resolve_block_template() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Moderate

Reads stored settings via get_option(), cached per request but not free on a cold cache.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

9

Executed per call on PHP 8.5. The body compiles to 82.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

3

3 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()one call below resolve_block_template()
• optionoption read or writeget_option()one call below resolve_block_template()

Further down the call graph this can also reach query, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost resolve_block_template() can have, taken from its control-flow graph on PHP 8.5.

Uses · 7

• get_block_templates()Retrieves a list of unified template objects based on a query.
• get_stylesheet_directory()Retrieves stylesheet directory path for the active theme.
• get_template_directory()Retrieves template directory path for the active theme.
• str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
• str_contains()Polyfill for `str_contains()` function added in PHP 8.0.
• _get_block_template_file()Retrieves the template file from the theme for a given slug.
• get_template()Retrieves name of the active theme.

Used by · 3

• WP_REST_Templates_Controller::get_template_fallback()Returns the fallback template for the given slug.
• _resolve_home_block_template()Returns the correct template for the site's home page.
• locate_block_template()Finds a block template with equal or higher specificity than a given PHP template file.

Source code

View on Trac ↗View on GitHub ↗

153function resolve_block_template( $template_type, $template_hierarchy, $fallback_template ) {154	if ( ! $template_type ) {155		return null;156	}157 158	if ( empty( $template_hierarchy ) ) {159		$template_hierarchy = array( $template_type );160	}161 162	$slugs = array_map(163		'_strip_template_file_suffix',164		$template_hierarchy165	);166 167	// Find all potential templates 'wp_template' post matching the hierarchy.168	$query     = array(169		'slug__in' => $slugs,170	);171	$templates = get_block_templates( $query );172 173	// Order these templates per slug priority.174	// Build map of template slugs to their priority in the current hierarchy.175	$slug_priorities = array_flip( $slugs );176 177	usort(178		$templates,179		static function ( $template_a, $template_b ) use ( $slug_priorities ) {180			return $slug_priorities[ $template_a->slug ] - $slug_priorities[ $template_b->slug ];181		}182	);183 184	$theme_base_path        = get_stylesheet_directory() . DIRECTORY_SEPARATOR;185	$parent_theme_base_path = get_template_directory() . DIRECTORY_SEPARATOR;186 187	// Is the active theme a child theme, and is the PHP fallback template part of it?188	if (189		str_starts_with( $fallback_template, $theme_base_path ) &&190		! str_contains( $fallback_template, $parent_theme_base_path )191	) {192		$fallback_template_slug = substr(193			$fallback_template,194			// Starting position of slug.195			strpos( $fallback_template, $theme_base_path ) + strlen( $theme_base_path ),196			// Remove '.php' suffix.197			-4198		);199 200		// Is our candidate block template's slug identical to our PHP fallback template's?201		if (202			count( $templates ) &&203			$fallback_template_slug === $templates[0]->slug &&204			'theme' === $templates[0]->source205		) {206			// Unfortunately, we cannot trust $templates[0]->theme, since it will always207			// be set to the active theme's slug by _build_block_template_result_from_file(),208			// even if the block template is really coming from the active theme's parent.209			// (The reason for this is that we want it to be associated with the active theme210			// -- not its parent -- once we edit it and store it to the DB as a wp_template CPT.)211			// Instead, we use _get_block_template_file() to locate the block template file.212			$template_file = _get_block_template_file( 'wp_template', $fallback_template_slug );213			if ( $template_file && get_template() === $template_file['theme'] ) {214				// The block template is part of the parent theme, so we215				// have to give precedence to the child theme's PHP template.216				array_shift( $templates );217			}218		}219	}220 221	return count( $templates ) ? $templates[0] : null;222}

Changelog

Introduced in 5.8.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/block-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

Something wrong on this page? Report it and it gets fixed in the next regeneration.