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validate_current_theme()

Checks that the current theme has ‘index.php’ and ‘style.css’ files.

Description

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 current theme does not validate.

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

See also

Return

(bool)

Source

File: wp-includes/theme.php

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

	if ( ! 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;
}

Changelog

Version Description
1.5.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/validate_current_theme