Keeping post_date same as the pending post_date on privately publishing the post

Question

I'm saving my CPT in private status. So the transition would be from pending to private. Thing is, when the post was first submitted and is pending there's a date of that submission on the post_date field in db. But when the post got published, the date updated with the current date.

I want to keep the original date of the submission of the post even the post privately published later.

So I did something like below:

function mycpt_keep_pending_date_on_publishing( $new_status, $old_status, $post ) {
    if( 'mycpt' === $post->post_type && 'pending' === $old_status && 'private' === $new_status ) :
        $pending_datetime = get_post_field( 'post_date', $post->ID, 'raw' );

        // Update the post  
        $modified_post = array(  
            'ID'            => $post->ID,  
            'post_date'     => $pending_datetime,
            'post_date_gmt' => get_gmt_from_date( $pending_datetime )
        );  

        // Update the post into the database  
        wp_update_post( $modified_post );

    endif;
}

add_action( 'transition_post_status', 'mycpt_keep_pending_date_on_publishing' );

But it's not working. What can be the reason?

Answer 1

@Howdy_McGee is on the right track in his comment: by the time transition_post_status is fired, the post has already been updated (i.e., written to the db).

What you need to do is hook into wp_insert_post_data, instead of transition_post_status, as follows:

add_filter ('wp_insert_post_data', 'mycpt_keep_pending_date_on_publishing', 10, 2) ;

function
mycpt_keep_pending_date_on_publishing ($data, $postarr)
{
    if ($data['post_type'] != 'mycpt') {
        return ($data) ;
        }

    // this check amounts to the same thing as transition_post_status(private, pending)
    if ('private' != $data['post_status'] || 'pending' != $postarr['original_post_status']) {
        return ($data) ;
        }

    $pending_datetime = get_post_field ('post_date', $data['ID'], 'raw') ;

    $data['post_date'] = $pending_datetime ;
    $data['post_date_gmt'] = get_gmt_from_date ($pending_datetime) ;

    return ($data) ;
}

Note: I used the same function name as you did, but the body of that function is different.

Answer 2

In addition to the other answers, here's a small plugin that makes sure the code is only executed once. In case the data is reset by a plugin running later, try using PHP_INT_MAX -1 as priority (not for publicly distributed plugins). In this case, you will have to set the same value for remove_filter(), else the callback will not get removed.

<?php
/**
 * Plugin Name: (WPSE) Static post date
 * Description: Keep the post date as the original date for posts published as private
 */
namespace WPSE;

add_filter( 'wp_insert_post_data', '\WPSE\save', 10, 2 );
function save( $post, $raw ) {
    if ( ! in_array( $post['post_status'], [ 'private', 'pending', ] ) ) {
        return $post;
    }
    if ( 'your_post_type' !== $post['post_type'] ) {
        return $post;
    }

    $date = get_post_field( 'post_date', $post['ID'], 'raw' );
    $post['post_date'] = $date;
    $post['post_date_gmt'] = get_gmt_from_date( $date );

    return $post;
}

add_action( 'transition_post_status', function() {
    # Make sure above callback is only triggered once
    remove_filter( 'wp_insert_post_data', '\WPSE\save' );
} );

IIRC your main problem with above code is, that the private_to_published filter was deprecated, so there is nothing specific enough aside from a post type status filter. Try the following plugin and see if it works (if your post type really is named mycpt):

<?php
/* Plugin Name: (WPSE) Test post type status actions */
add_action( 'private_mycpt', function( $ID, \WP_Post $post ) {
    var_dump( current_filter() );
    exit;
}, 10, 2 );