remove_all_filters() should set to array(), not unset

[nacin]

Consider this use case: You want to hook into priority 0 of an action and run remove_all_actions() for all other callbacks.

Since we use current() and next() to iterate, rather than making a copy of $wp_filter to loop through it, this should work.

Unfortunately, current() and next() expect an array, and only stop when next() returns === false. remove_all_filters() does an unset() on $wp_filter[$tag], which means next() returns A) a warning, and B) null. The null causes an indefinite loop.

Test code:

add_filter( 'test_filter', function() { remove_all_filters( 'test_filter' ); return 0; }, 0 );
add_filter( 'test_filter', function() { return 1; }, 1 );
add_filter( 'test_filter', function() { return 2; }, 2 );
var_dump( apply_filters( 'test_filter', -1 ) );