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Date: Wed, 8 Aug 2018 23:09:55 +0200
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Subject: object destruction php 5.6 vs. 7.2
From: nicolai.scheer@gmail.com (Nicolai Scheer)

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Hi,

I'm currently facing difficulties to migrate one of our extension from php
5.6 to 7.2.

Basically everything works fine.
The extension defines its own resource, and since it's object oriented,
stores the resource inside a member variable, i.e. we register the custom
resource using zend_list_insert followed by calling zend_update_property.

Every method then fetches the resource using zend_read_property and
zend_fetch_resource.
The resource itself has a dtor, which is registered
through zend_register_list_destructors_ex.

The class itself does not have a __destruct method.

Using php 5.6, when unsetting the object in userspace the resource dtor was
called immediately.

In php 7.2 this does not seem to be the case anymore - i.e. I see that the
resource dtor is called at script end, but not when unsetting the object in
userspace.
This results in php holding a lot of connections (that's what the resource
is about) up to the point where no new connection can be created (which is
bad).

I implemented and registered a __destruct method for testing purposes -
this one indeed gets called on object destruction triggered by unsetting
the variable in userspace.

So my question here ist: Can anyone give me an insight what is happening
here? I know, I posted not quite much information, but there must be
something fundamental I'm missing.

Basically I would expect, even if I do not implement a custom __destruct
method, that upon object deletion all members variables are deleted as well
- this would include the resource, and as such, the resource destructor
would be called.
That seems to be what is happening in php 5.6 but does not work in 7.2
anymore.

Of course I could move the code from the resource dtor to a __destruct
method - but what's the point in providing a resource destructor then (in
my case)? What is the correct way for a class to hold a (protected)
resource and make sure that resource gets destroyed correctly upon object
deletion?

Thanks for your help!

Greetings

Nico

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