validate_current_theme(): bool

Checks that the active theme has the required files.

Description

Standalone themes need to have a templates/index.html or index.php template file.
Child themes need to have a Template header in the style.css stylesheet.

Does not initially check the default theme, which is the fallback and should always exist.
But if it doesn’t exist, it’ll fall back to the latest core default theme that does exist.
Will switch theme to the fallback theme if active theme does not validate.

You can use the ‘validate_current_theme’ filter to return false to disable this functionality.

See also

Return

bool

Source

function validate_current_theme() {
	/**
	 * Filters whether to validate the active theme.
	 *
	 * @since 2.7.0
	 *
	 * @param bool $validate Whether to validate the active theme. Default true.
	 */
	if ( wp_installing() || ! apply_filters( 'validate_current_theme', true ) ) {
		return true;
	}

	if (
		! file_exists( get_template_directory() . '/templates/index.html' )
		&& ! file_exists( get_template_directory() . '/block-templates/index.html' ) // Deprecated path support since 5.9.0.
		&& ! file_exists( get_template_directory() . '/index.php' )
	) {
		// Invalid.
	} elseif ( ! file_exists( get_template_directory() . '/style.css' ) ) {
		// Invalid.
	} elseif ( is_child_theme() && ! file_exists( get_stylesheet_directory() . '/style.css' ) ) {
		// Invalid.
	} else {
		// Valid.
		return true;
	}

	$default = wp_get_theme( WP_DEFAULT_THEME );
	if ( $default->exists() ) {
		switch_theme( WP_DEFAULT_THEME );
		return false;
	}

	/**
	 * If we're in an invalid state but WP_DEFAULT_THEME doesn't exist,
	 * switch to the latest core default theme that's installed.
	 *
	 * If it turns out that this latest core default theme is our current
	 * theme, then there's nothing we can do about that, so we have to bail,
	 * rather than going into an infinite loop. (This is why there are
	 * checks against WP_DEFAULT_THEME above, also.) We also can't do anything
	 * if it turns out there is no default theme installed. (That's `false`.)
	 */
	$default = WP_Theme::get_core_default_theme();
	if ( false === $default || get_stylesheet() == $default->get_stylesheet() ) {
		return true;
	}

	switch_theme( $default->get_stylesheet() );
	return false;
}

Hooks

apply_filters( ‘validate_current_theme’, bool $validate )

Filters whether to validate the active theme.

Changelog

VersionDescription
6.0.0Removed the requirement for block themes to have an index.php template.
1.5.0Introduced.

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