woocommerce - add order notes to completed emails

gistfile1.php

<?php
add_action( 'woocommerce_email_order_meta', 'woo_add_order_notes_to_email' );

function woo_add_order_notes_to_email() {

	global $woocommerce, $post;

	$args = array(
		'post_id' 	=> $post->ID,
		'approve' 	=> 'approve',
		'type' 		=> 'order_note'
	);

	$notes = get_comments( $args );
	
	echo '<h2>' . __( 'Order Notes', 'woocommerce' ) . '</h2>';

	echo '<ul class="order_notes">';

	if ( $notes ) {
		foreach( $notes as $note ) {
			$note_classes = get_comment_meta( $note->comment_ID, 'is_customer_note', true ) ? array( 'customer-note', 'note' ) : array( 'note' );

			?>
			<li rel="<?php echo absint( $note->comment_ID ) ; ?>" class="<?php echo implode( ' ', $note_classes ); ?>">
				<div class="note_content">
					(<?php printf( __( 'added %s ago', 'woocommerce' ), human_time_diff( strtotime( $note->comment_date_gmt ), current_time( 'timestamp', 1 ) ) ); ?>) <?php echo wpautop( wptexturize( wp_kses_post( $note->comment_content ) ) ); ?>
				</div>
			</li>
			<?php
		}
	} else {
		echo '<li>' . __( 'There are no notes for this order yet.', 'woocommerce' ) . '</li>';
	}

	echo '</ul>';
}

I'm getting an error in my email :

Notice: Trying to get property of non-object in /home/my-project/public_html/wp-content/themes/default/functions.php on line 626

because of :

global $woocommerce, $post;

$args = array(
    'post_id'   => $post->ID, // line 626 error !
    'approve'   => 'approve',
    'type'      => 'order_note'
);

Try 'status' => 'approve',

In order for this to work in the latest woocommerce email templates, I needed to add

?>

to the end

I can see the comments are split between 'privat' and 'what the customer can see'.
Is it possible through this script only to show the 'customer comments'?

I need just to include a note where I post the tracking link.

It would be nice to indeed only add the tracking link that is posted as a customer note.

If all you need is the customer comments, try replacing this:

function woo_add_order_notes_to_email() {
	global $woocommerce, $post;
	$args = array(
		'post_id' 	=> $post->ID,
		'approve' 	=> 'approve',
		'type' 		=> 'order_note'
	);
	$notes = get_comments( $args );

with this:

function woo_add_order_notes_to_email($order) {
        $notes = $order->get_customer_order_notes();

Hello, great snippet of code but it applies to all the emails including the processing and invoice. Is there any way to target the completed email only?