0002258: Assignment to reference variables sometimes breaks in compiled mode

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Category

Severity

Reproducibility

Date Submitted

Last Update

0002258

[Quercus]

major

always

12-15-07 01:40

12-18-07 15:51

Reporter

koreth

View Status

public

Assigned To

ferg

Priority

normal

Resolution

fixed

Platform

Status

closed

Projection

none

OS Version

ETA

none

Fixed in Version

3.1.5

Product Version

3.1.4

Product Build

Summary

0002258: Assignment to reference variables sometimes breaks in compiled mode

Description

In a class, we call a function to queue up a data lookup for later, passing in a reference to a class variable that doesn't exist yet. Something like this:

class MyClass {
  function foo($id) {
    queue_up("myclass." . $id, $this->field);
  }
}

The queue_up function adds the reference to a list of pending lookups, something like this:

function queue_up($id, &$ref) {
  $GLOBALS['queue'][] = array('id' => $id, 'ref' => &$ref);
}

Then, later on, we call a dispatch function to perform all the pending lookups, something like this:

function dispatch() {
  ... do the actual lookups (this part works fine) ...
  foreach ($GLOBALS['queue'] as $item) {
    $id = $item['id'];
    $item['ref'][$id] = $looked_up_values[$id];
  }
}

The desired result is that $myclass_instance->field is an array with an entry whose key is the ID and whose value is the looked-up value. In vanilla PHP and in interpreted mode, this works fine. But when the dispatch function is compiled, it stops working; $myclass_instance->field gets created, but it is assigned an empty value.

A possibly big clue: if I tweak the dispatch function to look like

...
  foreach ($GLOBALS['queue'] as $item) {
    $id = $item['id'];
    $ref = &$item['ref'];
    $ref[$id] = $looked_up_values[$id];
  }

(that is, to explicitly access the reference as a reference before assigning to it) then the code starts working in compiled mode too. I'm doing that in a couple places in the code now as a workaround, but we make a lot of use of references and I'm sure there are still bad behaviors being caused by this bug.

Unfortunately I haven't been able to come up with a concise test case for this; in a test case as simple as the one above, the bug never occurs. But it is 100% reproducible in our actual code base. If there are syntax or logic errors in my example code above it's just because I made it up as I typed this report, not because that's what the real code does.

Steps To Reproduce

Additional Information

Attached Files

Relationships

Notes
(0002590) ferg 12-18-07 15:51	php/39o2

Issue History
Date Modified	Username	Field	Change
12-15-07 01:40	koreth	New Issue
12-18-07 15:51	ferg	Note Added: 0002590
12-18-07 15:51	ferg	Assigned To	=> ferg
12-18-07 15:51	ferg	Status	new => closed
12-18-07 15:51	ferg	Resolution	open => fixed
12-18-07 15:51	ferg	Fixed in Version	=> 3.1.5
12-18-07 15:51	ferg	Description Updated

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