php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #80073 levenshtein(): new ValueError not documented
Submitted: 2020-09-07 09:38 UTC Modified: 2020-10-09 14:15 UTC
From: claude dot pache at gmail dot com Assigned: nikic (profile)
Status: Closed Package: *General Issues
PHP Version: 8.0.0 OS:
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: claude dot pache at gmail dot com
New email:
PHP Version: OS:

 

 [2020-09-07 09:38 UTC] claude dot pache at gmail dot com 
Description:
------------
In the manual page:

https://www.php.net/manual/function.levenshtein.php

it is stated that levenshtein() returns -1 if one argument is too long, but it doesn’t say that an error is emitted.

Test script:
---------------
var_dump(levenshtein(str_repeat('X', 300), 'a'));

Expected result:
----------------
Per the manual page; dumps -1 without warning/error.

Actual result:
--------------
In PHP 7: Emits a Warning and dumps -1.

In PHP 8: Throws a ValueError.

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2020-09-07 09:52 UTC] claude dot pache at gmail dot com 
Moreover, the change of behaviour of levenshthein() between PHP 7 and PHP 8 (which is a BC break) is currently not documented in UPGRADING:

https://github.com/php/php-src/blob/php-8.0.0beta3/UPGRADING
 [2020-09-07 10:01 UTC] requinix@php.net
-Summary: levenshthein(): warning/error not documented +Summary: levenshtein(): new ValueError not documented -Status: Open +Status: Verified -PHP Version: Irrelevant +PHP Version: 8.0.0
 [2020-09-07 10:01 UTC] requinix@php.net 
Changed during https://github.com/php/php-src/pull/5816
 [2020-10-06 15:10 UTC] nikic@php.net 
I wonder if we can't just drop that error condition altogether. Why is there a limitation of 255 characters? My best guess is that it's supposed to protected against the quadratic time complexity of the algorithm. But then again, the similar_text() function which has much worse (cubic) complexity, does not come with such a limitation. This doesn't seem like something PHP should be enforcing.
 [2020-10-06 15:18 UTC] nikic@php.net
-Package: Documentation problem +Package: *General Issues -Assigned To: +Assigned To: nikic
 [2020-10-06 15:18 UTC] nikic@php.net 
PR to drop the check: https://github.com/php/php-src/pull/6286
 [2020-10-09 14:15 UTC] nikic@php.net
-Status: Verified +Status: Closed
 [2020-10-09 14:15 UTC] nikic@php.net 
The string length limitation and the accompanying ValueError are now gone...
 [2020-10-09 15:43 UTC] claude dot pache at gmail dot com 
There is still a documentation issue, which was the original purpose of this bug report.
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved. 		Last updated: Mon Dec 02 20:01:32 2024 UTC