Re: [RFC] Polling API

Hi, On Sun, Nov 23, 2025 at 4:05 PM Tim Düsterhus <tim@bastelstu.be> wrote: > Hi > > Apologies for the late reply. It was a few busy weeks leading up to the > PHP 8.5 Release. > > When searching for the RFC text I just noticed that it does not appear > to be listed in https://wiki.php.net/rfc#under_discussion yet. > > This is fixed. > > > > >> As an example PollContext::__construct() should probably throw a > >> BackendUnavailableException or something like this. For > >> PollContext::add() I'm wondering in which cases a handle “cannot be > >> added”. > > > > > > It fails if the same fd is added. This is also limitation of backends > (e.g. > > epoll does not allow the same fd to be added twice). I got error code for > > the specific errors so this should be probably exposed as well. It would > > still make sense to differentiate that it's an exception for addition. > > I see. I was wondering if it would make sense to simply ignore the > error, thus making the operation idempotent (more convenient for a > high-level language like PHP). But I suppose that doesn't work, because > the $data could be different? > > Yeah data and events can be different. > Exception-wise this should probably be a DuplicateHandleError (i.e. > within the Error hierarchy, since it's a programming error to add > duplicate handles). > > I don't think users should be expected to keep track of added handles. So I think that this is something that can be nicely handled and in some cases it will be just fine to just catch it and ignore. So I wouldn't see this as a programmer error and therefore the exception is more appropriate IMHO. I created a specific exception for this called \Io\Poll\HandleAlreadyWatchedException so it will be easy for users to differentiate it. Kind regards, Jakub