<?php 
/** 
 * Server-side rendering of the `core/button` block. 
 * 
 * @package WordPress 
 */ 
 
/** 
 * Renders the `core/button` block on the server, 
 * 
 * @since 6.6.0 
 * 
 * @param array    $attributes The block attributes. 
 * @param string   $content    The block content. 
 * @param WP_Block $block      The block object. 
 * 
 * @return string The block content. 
 */ 
function render_block_core_button( $attributes, $content ) { 
    $p = new WP_HTML_Tag_Processor( $content ); 
 
    /* 
     * The button block can render an `<a>` or `<button>` and also has a 
     * `<div>` wrapper. Find the a or button tag. 
     */ 
    $tag = null; 
    while ( $p->next_tag() ) { 
        $tag = $p->get_tag(); 
        if ( 'A' === $tag || 'BUTTON' === $tag ) { 
            break; 
        } 
    } 
 
    /* 
     * If this happens, the likelihood is there's no block content, 
     * or the block has been modified by a plugin. 
     */ 
    if ( null === $tag ) { 
        return $content; 
    } 
 
    // If the next token is the closing tag, the button is empty. 
    $is_empty = true; 
    while ( $p->next_token() && $tag !== $p->get_token_name() && $is_empty ) { 
        if ( '#comment' !== $p->get_token_type() ) { 
            /** 
             * Anything else implies this is not empty. 
             * This might include any text content (including a space), 
             * inline images or other HTML. 
             */ 
            $is_empty = false; 
        } 
    } 
 
    /* 
     * When there's no text, render nothing for the block. 
     * See https://github.com/WordPress/gutenberg/issues/17221 for the 
     * reasoning behind this. 
     */ 
    if ( $is_empty ) { 
        return ''; 
    } 
 
    return $content; 
} 
 
/** 
 * Registers the `core/button` block on server. 
 * 
 * @since 6.6.0 
 */ 
function register_block_core_button() { 
    register_block_type_from_metadata( 
        __DIR__ . '/button', 
        array( 
            'render_callback' => 'render_block_core_button', 
        ) 
    ); 
} 
add_action( 'init', 'register_block_core_button' ); 
 
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