functions.php

<?php

/**
 * Do not edit anything in this file unless you know what you're doing
 */

/**
 * Require Composer autoloader if installed on it's own
 */
if (file_exists($composer = __DIR__ . '/vendor/autoload.php')) {
    require_once $composer;
}

/**
 * Here's what's happening with these hooks:
 * 1. WordPress detects theme in themes/sage
 * 2. When we activate, we tell WordPress that the theme is actually in themes/sage/templates
 * 3. When we call get_template_directory() or get_template_directory_uri(), we point it back to themes/sage
 *
 * We do this so that the Template Hierarchy will look in themes/sage/templates for core WordPress themes
 * But functions.php, style.css, and index.php are all still located in themes/sage
 *
 * themes/sage/index.php also contains some self-correcting code, just in case the template option gets reset
 */
add_filter('stylesheet', function ($stylesheet) {
    return dirname($stylesheet);
});
add_action('after_switch_theme', function () {
    $stylesheet = get_option('stylesheet');
    if (basename($stylesheet) !== 'templates') {
        update_option('stylesheet', $stylesheet . '/templates');
    }
});
add_action('customize_render_section', function ($section) {
    if ($section->type === 'themes') {
        $section->title = wp_get_theme(basename(__DIR__))->display('Name');
    }
}, 10, 2);

/**
 * Sage includes
 *
 * The $sage_includes array determines the code library included in your theme.
 * Add or remove files to the array as needed. Supports child theme overrides.
 *
 * Please note that missing files will produce a fatal error.
 */
$sage_includes = [
    'src/helpers.php',
    'src/setup.php',
    'src/filters.php',
    'src/admin.php'
];
array_walk($sage_includes, function ($file) {
    if (!locate_template($file, true, true)) {
        trigger_error(sprintf(__('Error locating %s for inclusion', 'sage'), $file), E_USER_ERROR);
    }
});