[PHP-BUG] Bug #71252 [NEW]: yield from ignores yield-by-reference

[email protected] ("[email protected]")
Newsgroups php.bugs
Message-ID <[email protected]>
From:             nikic
Operating system: 
PHP version:      7.0Git-2015-12-30 (Git)
Package:          Scripting Engine problem
Bug Type:         Bug
Bug description:yield from ignores yield-by-reference

Description:
------------
When "yield from" was implemented, we did not consider how it interacts
with yield-by-reference. Right now it is simply ignored and "yield from"
yields all values by-value.

Likely this is not the expected or intended behavior. Instead "yield
from" in a by-reference generator should yield array values and values
from by-reference generators by-reference. "yield from" should generate
an error for iterators (and generators) that do not support by-reference
iteration.

Test script:
---------------
<?php
function &gen(array $array) {
    yield from $array;
}

$array = [1, 2, 3];
foreach (gen($array) as &$v) {
    $v += 1;
}
var_dump($array);

Expected result:
----------------
array(3) {
  [0]=>
  int(2)
  [1]=>
  int(3)
  [2]=>
  int(4)
}


Actual result:
--------------
array(3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
}


-- 
Edit bug report at https://bugs.php.net/bug.php?id=71252&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=71252&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=71252&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=71252&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=71252&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=71252&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=71252&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=71252&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=71252&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=71252&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=71252&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=71252&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=71252&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=71252&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=71252&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=71252&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=71252&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=71252&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=71252&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=71252&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=71252&r=mysqlcfg
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.