Change array_combine behaviour when called with empty arrays

Submitted:

2005-10-13 15:07 UTC

Modified:

2010-08-27 05:54 UTC

Votes:	15
Avg. Score:	4.3 ± 0.7
Reproduced:	14 of 14 (100.0%)
Same Version:	3 (21.4%)
Same OS:	5 (35.7%)

From:

stochnagara at hotmail dot com

Assigned:

aharvey (profile)

Status:

Closed

Package:

Arrays related

PHP Version:

5.1.0RC1

OS:

Private report:

CVE-ID:

None

[2005-10-13 15:07 UTC] stochnagara at hotmail dot com

Description:
------------
Currently array_combine returns false and raises a warning if it is used with two empty array and this is documented too.
This is quite inconsistent since combining two empty arrays is expected to result in another empty array.
If there are so many BC arguments, then this function could be extended with a third optional argument 'accept_empty' which allow the thing I request.

P.S. Actually bug #29972 is almost the same and has been marked closed so this could be a reopen of this bug.

Reproduce code:
---------------
<?php
var_dump (array_combine (array(), array()));
?>


Expected result:
----------------
array(0) { }

Actual result:
--------------
Warning: array_combine() [function.array-combine]: Both parameters should have at least 1 element in C:\Program Files\Apache Group\Apache2\htdocs\boroinvest\test.php on line 3
bool(false)

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[2008-12-21 22:05 UTC] ms419 at freezone dot co dot uk

I am trying to parse the output of "svnlook proplist -v" into an associative array of property keys and property values:

            $pattern = '/^  ([^ ]+) : ((?:\V|\v[^ ]|\v [^ ])+)/m';
            if (false === preg_match_all($pattern, $subject, $matches)) {

                // Error handling
            }

            return array_combine($matches[1], $matches[2]);

This works great, unless "svnlook proplist -v" finds no properties. In that case, array_combine() returns false because array() === $matches[1] and array() === $matches[2].

Consequently, I am forced to treat the case when "svnlook proplist -v" finds no properties as a special case.

I wish array() === array_combine(array(), array()), as I assumed it would.

[2010-08-27 05:43 UTC] aharvey@php.net

-Status: Open +Status: Assigned -Package: Feature/Change Request +Package: *General Issues -Assigned To: +Assigned To: aharvey

[2010-08-27 05:44 UTC] aharvey@php.net

-Package: *General Issues +Package: Arrays related

[2010-08-27 05:54 UTC] aharvey@php.net

-Summary: Change array_combine behavoiur +Summary: Change array_combine behaviour when called with empty arrays -Status: Assigned +Status: Closed

[2010-08-27 05:54 UTC] aharvey@php.net

This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

Thanks very much for the patch, Joel.