BP_Group_Member_Query should support multiple group IDs

[r-a-y]

Sometimes it is useful to query for members from multiple groups.

Currently, we cannot do this with BP_Group_Member_Query since it only supports one group ID.

Attached patch allows for passing multiple group IDs.

[dcavins]

Hi @r-a-y-

I think this is a great idea. In your attached patch, what would trigger the else condition:

else { 
    $group_ids_sql = $wpdb->prepare( "group_id = %d", $this->query_vars['group_id'] );  
}

Maybe if an empty array or empty string was passed into the function? I guess I'm wondering, is there a value that you could pass that would be stripped down to an empty array by wp_parse_id_list(), but would be useful to do an equals check on?

Thanks for setting me straight. :)

[r-a-y]

@dcavins - You're right. The else condition is not necessary.

I guess I was just being extra cautious, but wp_parse_id_list() should handle most empty instances and default to array( 0 ), so we should be safe to remove the else condition.

[dcavins]

Replying to r-a-y:

@dcavins - You're right. The else condition is not necessary.

I guess I was just being extra cautious, but wp_parse_id_list() should handle most empty instances and default to array( 0 ), so we should be safe to remove the else condition.

Not so fast! :)

I think we need an else condition, because wp_parse_id_list( array() ) does return an empty array. But maybe the else condition should be explicitly not made to work, like group_id = 0 or something. I was just wondering, could there be a passed arg that would be useful? I can't think of one.

Thanks again for this good idea!

[r-a-y]

Well, if you're passing an empty array, then you're SOL :)

I suppose we could do something like this:

$group_ids = wp_parse_id_list( $this->query_vars['group_id'] ); 
$group_ids = ! empty( $group_ids ) ? $group_ids : array( 0 );

Feels a little unnecessary, but meh!

[DJPaul]

if someone passes a null-ish value to group_id and if we don't explicitly support that already, we do not need to protect against developer stupidity. This is our lowest-level query function for Groups Members queries, and any handholding like this should happen up the chain.

tl;dr 02 patch looks good

[DJPaul]

@r-a-y Are you still up for committing this to trunk?

[DJPaul]

Fair warning, I'm going to add this next week @r-a-y unless you say otherwise.

[DJPaul]

This needs a bit more work, I don't think the else clause in the patch is ever going to be hit.

[r-a-y]

Second patch doesn't use the else condition.

[DJPaul]

Yeah I like it, get it in!

[djpaul]

In 11792:

Groups: add support to query for members from multiple groups.

Fixes #7573

Props r-a-y, dcavins