get_avatar_data filter hook runs twice per request

[henry.wright]

If you run this test function hooked to get_avatar_data, you should see $var gets dumped twice:

add_filter( 'get_avatar_data', function( $args, $id_or_email ) {
    $var = 'foo';
    var_dump( $var );
    return $args;
}, 10, 2 );

[SergeyBiryukov]

It's intentional, see the discussion in #32572.

[henry.wright]

On pages with lots of avatars, wp-admin/users.php for example, this filter will already be running ~10 times, so increasing that figure to ~20 unnecessarily seems inefficient?

[rachelbaker]

As noted in #32572 this is intentional behavior and the performance impact is negligible. https://core.trac.wordpress.org/ticket/32572#comment:23