WordPress多站点插件激活触发致命错误，求技术解决方案

Hey there, let's break down this error and fix it step by step! That fatal error you're seeing has nothing to do with switching false to true—it's a PHP compatibility issue, plus a small logic structure mistake in your code. Here's what's going on and how to fix it:

What's Causing the Error? #

Before PHP 5.5, the empty() function can't accept a function's return value directly (like empty(get_option(...))). It only works with variables. Your code does exactly this in two places, which triggers the fatal error. On top of that, your second conditional has a messed-up bracket structure that's breaking the intended logic.

Step 1: Fix the Update Notice Conditional (Line 15) #

Your original line 15 code:

/* Change to true */ if (false == defined( 'CWCFP_PLUGIN' ) && empty( get_option( 'cwcfp-update-notice-dismissed' ) ) ){ add_action( 'admin_notices', 'cwcf_update_notice' ); }

Replace it with this corrected version:

/* Change to true */
$dismissed_update_notice = get_option( 'cwcfp-update-notice-dismissed' );
if ( !defined( 'CWCFP_PLUGIN' ) && empty( $dismissed_update_notice ) ) {
    add_action( 'admin_notices', 'cwcf_update_notice' );
}

• We first store the result of get_option() in a variable ($dismissed_update_notice), which makes it compatible with older PHP versions.
• Swapped false == defined() for !defined() to make the code more readable—this does the exact same check, just cleaner.

Step 2: Fix the Review Notice Conditional #

Your original review notice code has both the empty() function issue and a bracket error:

/* Change to true */ if ( false == defined( 'CWCFP_PLUGIN' ) && empty( get_option( 'cwcf-review-notice-dismissed' ) && !empty( get_option( 'cwcfp-update-notice-dismissed' ) ) ) ){ add_action( 'admin_notices', 'cwcf_review_notice' ); }

Replace it with this:

/* Change to true */
$dismissed_review_notice = get_option( 'cwcf-review-notice-dismissed' );
$dismissed_update_notice = get_option( 'cwcfp-update-notice-dismissed' );
if ( !defined( 'CWCFP_PLUGIN' ) && empty( $dismissed_review_notice ) && !empty( $dismissed_update_notice ) ) {
    add_action( 'admin_notices', 'cwcf_review_notice' );
}

• Again, we store get_option() results in variables first to fix the empty() compatibility issue.
• Fixed the bracket structure to correctly implement your intended logic: show the review notice only if the Pro plugin isn't active, the review notice hasn't been dismissed, and the update notice HAS been dismissed.

Full Corrected Plugin Code #

Here's how the full fixed code will look:

<?php
if ( ! defined( 'ABSPATH' ) ) {
    exit; // Exit if accessed directly
}

function cwcf_update_notice() {
    $url = 'https://conditionalcheckoutfields.com/downloads/conditional-woo-checkout-field-pro/';
    $link = sprintf(
        wp_kses(
            __( '<a href="%s">Click here</a> to upgrade Conditional Checkout Field to Pro! Get an unlimited number of checkout fields, duplicate checkout fields based on product quantity in the customer\'s cart, and more!', 'conditional-woo-checkout-field' ),
            array( 'a' => array( 'href' => array() ) )
        ),
        esc_url( $url )
    );
    ?>
    <div class="notice notice-info cwcfp-update-notice is-dismissible">
        <p><?php echo $link; ?></p>
    </div>
    <?php
}

/* Change to true */
$dismissed_update_notice = get_option( 'cwcfp-update-notice-dismissed' );
if ( !defined( 'CWCFP_PLUGIN' ) && empty( $dismissed_update_notice ) ) {
    add_action( 'admin_notices', 'cwcf_update_notice' );
}

add_action( 'admin_enqueue_scripts', 'cwcf_update_notice_assets' );
function cwcf_update_notice_assets() {
    wp_enqueue_script( 'cwcfp-notice-update', CWCF_PLUGIN_URL . '/includes/js/notice-update.js', array( 'jquery' ), '1.0', true );
    wp_enqueue_script( 'cwcf-notice-review', CWCF_PLUGIN_URL . '/includes/js/notice-review.js', array( 'jquery' ), '1.0', true );
}

add_action( 'wp_ajax_cwcfp_dismiss_notice', 'cwcfp_dismiss_notice' );
function cwcfp_dismiss_notice(){
    update_option( 'cwcfp-update-notice-dismissed', '1' );
}

function cwcf_review_notice() {
    $url = 'https://wordpress.org/support/plugin/conditional-woo-checkout-field/reviews/#new-post';
    $link = sprintf(
        wp_kses(
            __( 'Could we ask for a 5 star review of Conditional Checkout Field? It would be greatly appreciated! <a href="%s">Click here</a> to leave a review.', 'conditional-woo-checkout-field' ),
            array( 'a' => array( 'href' => array() ) )
        ),
        esc_url( $url )
    );
    ?>
    <div class="notice notice-info cwcf-review-notice is-dismissible">
        <p><?php echo $link; ?></p>
    </div>
    <?php
}

/* Change to true */
$dismissed_review_notice = get_option( 'cwcf-review-notice-dismissed' );
$dismissed_update_notice = get_option( 'cwcfp-update-notice-dismissed' );
if ( !defined( 'CWCFP_PLUGIN' ) && empty( $dismissed_review_notice ) && !empty( $dismissed_update_notice ) ) {
    add_action( 'admin_notices', 'cwcf_review_notice' );
}

add_action( 'wp_ajax_cwcf_review_dismiss_notice', 'cwcf_review_dismiss_notice' );
function cwcf_review_dismiss_notice(){
    update_option( 'cwcf-review-notice-dismissed', '1' );
}

Why This Works #

• Storing get_option() results in variables before using empty() makes your code compatible with all PHP versions supported by WordPress (including older versions <5.5).
• The corrected bracket structure ensures your notice display logic works exactly as you intended, without wrapping complex expressions inside empty().

内容的提问来源于stack exchange，提问作者Kevin.a