Perhaps you could add something like:

piklist('get_post_custom', $post_id, array( 'add_more_array_type' => 'by_lines' ) );

The third parameter being a set of options for this function (or could be merged with second parameter into a single array).
This would return the rotated array for add_more fields in case of ‘by_lines’ or the new behaviour with ‘by_field’ value (default).
That would make it easier to retrieve the values of those add_more fields.

Another method needed would be a helper to save back those meta data. The purpose here is to hide completely the actual data format from the user, so that you could in the future change it if you need without breaking existing codes.
Perhaps a mirror to ‘get_post_custom’: ‘set_post_custom’ with similar parameters plus the array of fields/values to store (the new option “add_more_array_type” to tell the method how the input array is formed).

That would make things extra easy to pull all meta data, modify one value in a field by changing the returned array and then store everything back.

Perhaps also one might need more granularity to load/save only one field at a time (wrapper around get_post_meta).

What do you reckon?

This problem is indeed fixed in beta6.

I can see there are big changes in the format of those add_more metas: the array is inverted. When it was once an array of lines, it is now an array of columns (first key being the name of the field, second being the line).
Am I correct?

That will change several parts of my code, which is understable because there’s a beta label after those 0.8 releases but it would be great to see a little note about these kinds of changes, especially data format, in a release note.
This is just a gentle advice, that doesn’t take anything away from the hard work you put in releases in general. Cheers guys.

Any news about this bug?

Not sure the code will helps as it’s more of a feature request than a bug report.

Here it is nonetheless:

myplugin.php:

$post_types['my_model'] = array(
'labels' => piklist('post_type_labels', 'Models'),
'public' => true,
'supports' => array('title', 'revisions'),
'rewrite' => array( 'slug' => 'my-model' ),
'capability_type' => 'post',
);


parts/meta-boxes/product.php:

/*
Title: Product Reference
Description:
Post Type: my_product
*/
piklist('field', array(
'type' => 'post-relate',
'scope' => 'my_model',
'label' => 'Model',
'description' => 'Model associated to this product',
'position' => 'wrap'));


From that basis I’d like to define the relationship between a Product and its Model via a selectbox instead of the current checkbox UI. The reasons are detailed in the first post.