Re: Weak Closures

That's very strange, I had thought it might be a bug. For simple use cases where an object references it's own closure it might be a memory leak, but for complex event loops it potentially allows unnecessary code to run indefinitely. I'm afraid I don't know any more than that. Thanks for the tip though. On Sat, 22 Jan 2022, 15:30 Christoph M. Becker, <cmbecker69@gmx.de> wrote: > On 21.01.2022 at 11:31, Dominic Grostate wrote: > > > I'd like to express my interest in a possible feature concerning weak > > references. Currently closures created within a class appear to > > contain a reference to the object that created it. This is of course > > necessary in order for the closure to retain the necessary scope. > > However I would like to suggest we have the option for closure to > > weakly reference this object so that when the object is garbage > > collected, the closure too may be rendered null or invalid > > (inspectable). > > > > Consider the following example: > > > > https://gist.github.com/orolyn/7651e4127759aad1736547490baa1394 > > > > The idea here is that without unset($sample) the loop would run > > forever, because there is a reference to the callback from the object, > > and in turn there is a reference to the object from the main stack. > > With the unset($sample), the idea is that before the callback is even > > called, the reference to the object is destroyed thusly so is the > > reference to callback, and since the callback is only referenced now > > in a WeakMap, the callback will finally be gone. > > > > In reality it appears there is a circular reference between the object > > and the callback. I don't know if this is a bug or not, because from > > what I can find PHP was fixed a long time ago to resolve circular > > references. > > > > However if this is intentional, I would like the option to make the > > closure weak for example: > > > > $c = WeakClosure::fromCallable(function () {}); > > $c = Closure::fromCallable(function () {}, true); > > > > Please let me know your thoughts, because maybe there is a way of > > achieving this with PHP as is. > > If you trigger the garbage collector manually (i.e. call > gc_collect_cycles() after unset($callback)), the loop terminates right > away. I'm not sure why it doesn't without manually triggering the GC. > > Christoph >