privatemsg_user_load should handle array of user ids

About the comments, no :)

http://ch2.php.net/array_intersect_key is a nice function but PHP 5 only and we currently don't require that for the Drupal 6 versions. So I guess the question is if we want to drop PHP 4 support for a handy little function that saves us 3 lines of code or so :)

I'm not sure how many are still using PHP 4 but when we accidently added something that required PHP 5 in the past, we sooner or later got a bug report about it. I guess we can try again and see what happens... :)

Tests would be good since just passing in user_1 triggers like 4 warnings. But we can do that while writing tests for #1033378: $subject in privatemsg_get_link() should be url encoded

No tests for this in #1033378: $subject in privatemsg_get_link() should be url encoded because the needed URL can't be generated by privatemsg_get_link() but it should be very similiar to write one, wanna try?

See also http://blog.worldempire.ch/de/story/writing-automated-tests-drupal-7

(not many differences re: test writing in D6 and 7)

SUbscribing

Decided to commit this because it is tested *a lot* with the change in #1034378: Add more recipient types to 'list' sql query. :)

Will need to verify how the situation is in D7, since core is already providing a statically cached user load function. Will maybe require some changes too.

D7 part is handled in #1034378: Add more recipient types to 'list' sql query.