acf/load_field alters $post?

• YourMark

• February 25, 2014 at 8:16 pm

Hello,

I am currently working on a site for a volleyballclub and the backend is stuffed with ACF fields. So far a good thing 🙂

They can add teams of their own and opponents and whenever they add a match they can pick a home and an away team. Those fields are ACF dropdowns filled with the load_field filter like this:

public function pre_populate_forms() {
	# Fill the home and away team dropdowns
	add_filter( 'acf/load_field/name=match_home_team', array( $this, 'pre_populate_teams_dropdown' ), 10, 3 );
	add_filter( 'acf/load_field/name=match_away_team', array( $this, 'pre_populate_teams_dropdown' ), 10, 3 );
	add_filter( 'acf/load_field/name=staff_name', array( $this, 'pre_populate_teams_staff_names' ), 10, 3 );
}

public function pre_populate_teams_dropdown( $field ) {
	$field['choices'] = array();

	$apollo_home_args = array(
		'post_type' => 'teams',
		'nopaging' => true,
	);

	$apollo_home_teams = new WP_Query( $apollo_home_args );

	if( $apollo_home_teams->have_posts() ) :
		while( $apollo_home_teams->have_posts() ) : $apollo_home_teams->the_post();
			$field['choices']['Apollo'][get_the_ID()] = get_the_title();
		endwhile;
		wp_reset_postdata();
	endif;

	$apollo_away_args = array(
		'post_type' => 'opponents',
		'nopaging' => true,
	);

	$apollo_away_teams = new WP_Query( $apollo_away_args );

	if( $apollo_away_teams->have_posts() ) :
		while( $apollo_away_teams->have_posts() ) : $apollo_away_teams->the_post();
			$field['choices'][__( 'Opponents', 'apollo' )][get_the_ID()] = get_the_title();
		endwhile;
		wp_reset_postdata();
	endif;

	return $field;
}

https://gist.github.com/YourMark/b7880476e7bd3d4087b6

So far so good. The fields are filled and the teams appear. But somewhere along the lines it looks like the load_field filter is altering the $post variable. I can not yet pinpoint exactely where yet, but when the post is saved, the $post variable suddenly consists of the last added team in the dropdown.

I was unable to find more examples of this, so maybe it’s a bug, maybe I am doing something wrong and maybe it’s something entirely new to you.

I am hoping you can help me out here. I am not sure weather I posted this in the right forum, so if it’s in the wrong place, feel free to move it.

Regards,

Mark

• YourMark

• February 25, 2014 at 8:25 pm

Little addendum:

If I var_dump the $post variable in pre_populate_teams_dropdown I get this:

object(WP_Post)[8885]
  public 'ID' => int 5084
  public 'post_author' => string '1' (length=1)
  public 'post_date' => string '2014-02-25 10:23:54' (length=19)
  public 'post_date_gmt' => string '0000-00-00 00:00:00' (length=19)
  public 'post_content' => string '' (length=0)
  public 'post_title' => string '' (length=0)
  public 'post_excerpt' => string '' (length=0)
  public 'post_status' => string 'auto-draft' (length=10)
  public 'comment_status' => string 'open' (length=4)
  public 'ping_status' => string 'open' (length=4)
  public 'post_password' => string '' (length=0)
  public 'post_name' => string '' (length=0)
  public 'to_ping' => string '' (length=0)
  public 'pinged' => string '' (length=0)
  public 'post_modified' => string '2014-02-25 10:23:54' (length=19)
  public 'post_modified_gmt' => string '0000-00-00 00:00:00' (length=19)
  public 'post_content_filtered' => string '' (length=0)
  public 'post_parent' => int 0
  public 'guid' => string 'http://loc.apollo8.nl/?post_type=matches&p=5084' (length=47)
  public 'menu_order' => int 0
  public 'post_type' => string 'matches' (length=7)
  public 'post_mime_type' => string '' (length=0)
  public 'comment_count' => string '0' (length=1)
  public 'filter' => string 'raw' (length=3)
object(WP_Post)[8714]
  public 'ID' => int 4438
  public 'post_author' => string '1' (length=1)
  public 'post_date' => string '2014-02-01 18:01:42' (length=19)
  public 'post_date_gmt' => string '2014-02-01 17:01:42' (length=19)
  public 'post_content' => string '' (length=0)
  public 'post_title' => string 'Heren 1' (length=7)
  public 'post_excerpt' => string '' (length=0)
  public 'post_status' => string 'publish' (length=7)
  public 'comment_status' => string 'open' (length=4)
  public 'ping_status' => string 'open' (length=4)
  public 'post_password' => string '' (length=0)
  public 'post_name' => string 'heren-1' (length=7)
  public 'to_ping' => string '' (length=0)
  public 'pinged' => string '' (length=0)
  public 'post_modified' => string '2014-02-01 18:01:42' (length=19)
  public 'post_modified_gmt' => string '2014-02-01 17:01:42' (length=19)
  public 'post_content_filtered' => string '' (length=0)
  public 'post_parent' => int 0
  public 'guid' => string 'http://loc.apollo8.nl/teams/heren-1/' (length=36)
  public 'menu_order' => int 0
  public 'post_type' => string 'teams' (length=5)
  public 'post_mime_type' => string '' (length=0)
  public 'comment_count' => string '0' (length=1)
  public 'filter' => string 'raw' (length=3)

So the first time it’s ok, but the second round it changes somehow.

And if I disable one of the dropdowns, it also seems to work ok. So this problem only occurs if both dropdowns are being pre_filled.

• Elliot

• February 26, 2014 at 10:43 am

Hi @YourMark

Because your filter is creating a new WP_Query object, and using the function $apollo_home_teams->the_post();, the global $post will be over written.

The best solutions is to not use WP_Query, but instead, use the get_posts function and loop over the results like an array.

Thanks
E

• YourMark

• February 26, 2014 at 7:05 pm

Hello Elliot,

I changed it to:

publicic function pre_populate_teams_dropdown( $field ) {
	global $post;
	//var_dump( $post );
	$field['choices'] = array();

	$apollo_home_args = array(
		'post_type' => 'teams',
		'nopaging' => true,
	);

	$apollo_home_teams = get_posts( $apollo_home_args );

	if( count( $apollo_home_teams ) > 0 ) :
		foreach( $apollo_home_teams as $team ) {
			$field['choices']['Apollo'][ $team->ID ] = get_the_title( $team->ID );
		}
	endif;

	$apollo_away_args = array(
		'post_type' => 'opponents',
		'nopaging' => true,
	);

	$apollo_away_teams = geT_posts( $apollo_away_args );

	if( count( $apollo_away_teams ) > 0 ) :
		foreach( $apollo_away_teams as $team ) {
			$field['choices']['Apollo'][ $team->ID ] = get_the_title( $team->ID );
		}
	endif;

	return $field;
}

This works, however it strikes me as odd. The function get_posts uses WP_Query too and the wp_reset_postdata() filter makes sure the $post variable is restored. So somehow the $post variable isn’t reset the way it should.

• YourMark

• February 26, 2014 at 8:30 pm

public function pre_populate_teams_dropdown( $field ) {
	$field['choices'] = array();

	$apollo_home_args = array(
		'post_type' => 'teams',
		'nopaging' => true,
		'fields' => 'ids',
	);

	$apollo_home_teams = new WP_Query( $apollo_home_args );

	if( $apollo_home_teams->have_posts() ) :
		while( $apollo_home_teams->have_posts() ) : $apollo_home_teams->the_post();
			$field['choices']['Apollo'][$post] = get_the_title( $post );
		endwhile;
		wp_reset_postdata();
	endif;

	$apollo_away_args = array(
		'post_type' => 'opponents',
		'nopaging' => true,
		'fields' => 'ids',
	);

	$apollo_away_teams = new WP_Query( $apollo_away_args );

	if( $apollo_away_teams->have_posts() ) :
		while( $apollo_away_teams->have_posts() ) : $apollo_away_teams->the_post();
			$field['choices'][__( 'Opponents', 'apollo' )][$post] = get_the_title( $post );
		endwhile;
		wp_reset_postdata();
	endif;

	return $field;
}

Appears to work as well.

• YourMark

• March 14, 2014 at 10:22 pm

This remains a strange case. Somehow the wp_reset_postdata() isn’t working well. I’m still not sure weather it’s WP or ACF that’s messing up, but either one of them is. Perhaps something to look into.