Should the engine be able to pass variables by reference of userland functions

3 years ago by G. P. B. — view source — reply

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Hello internals,

While working on cleaning up the FCI/FCC API I stumbled upon the
zend_fcall_info_args_ex()
function.
This function allows the engine to pass "variables" to userland functions
that expect a by-ref parameter.
This is currently only used within php-src in PDO when calling the
constructor of classes where the result of a statement should be stored in
PDO::FETCH_CLASS mode.

I am wondering if this makes any sense to continue support in general, and
thus in this specific case. As every other engine call to userland function
passes by value.

A PR of this change is located:
https://github.com/php/php-src/pull/9725/files

What are your opinions?

Best regards,

George P. Banyard

3 years ago by Kamil Tekiela — view source — reply

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Hi,

I am not sure if we should still support it. But I don't think it's
unthinkable to expect such feature from PHP. However, personally, I don't
find pass-by-ref that useful in general. The question is whether this
feature is used a lot in the wild.

If we decide to drop support for this, it should probably go through a
deprecation phase.

Regards,
Kamil

3 years ago by Jordan LeDoux — view source — reply

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Hi,

I am not sure if we should still support it. But I don't think it's
unthinkable to expect such feature from PHP. However, personally, I don't
find pass-by-ref that useful in general. The question is whether this
feature is used a lot in the wild.

If we decide to drop support for this, it should probably go through a
deprecation phase.

Regards,
Kamil

Pass by-ref is used a LOT in the wild, but I didn't interpret George's
question as "should we remove pass by-ref from userland entirely". Surely
the engine also supports pass by-ref somewhere in the VM as well as the
place that was mentioned, it just does it in a different way?

Jordan