Edit report at https://bugs.php.net/bug.php?id=61660&edit=1
ID: 61660
Comment by: personal_homepage_tools at hochsitze dot com
Reported by: krtek4+php at gmail dot com
Summary: bin2hex(hex2bin($data)) != $data
Status: Re-Opened
Type: Bug
Package: *General Issues
Operating System: Debian Linux
PHP Version: 5.4.1RC1
Assigned To: nikic
Block user comment: N
Private report: N
New Comment:
This is hardly believable. This bug is so much obvious that it hurts to read the comment "The
reason is simple: A padding can be either added on the left or on the right. E.g. "af52b"
could be interpreted both as "0af52b" and as "af52b0".". Anybody writing
this must have failed in CS101 (hard!) - how is it working that persons who write this still
obviously work for this company?
I know it is hard to get something as old as PHP in a functional, future-oriented state, but as long
as comments like this from official @php.net accounts are not deleted immediately this will not
happen IMHO.
Previous Comments:
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[2012-04-26 21:22:12] nikic@php.net
@Stas: Just to be sure we are on the same page:
a) This does not break BC in any significant way. Using the function with odd length was wrong from
the start. It definitely breaks less than other changes that landed to all branches, like the
handling of invalid multibyte sequences in json_encode.
b) If we don't change it now, it will be hard to do so later. PHP 5.4 isn't used much yet,
so people didn't have much chance to misuse this function. This may change in the future.
c) From hour long discussions on IRC it turns out that this is largely a documentation problem. Most
people involved in the discussion thought that hex2bin() converts hexadecimal numbers to binary
numbers (which is wrong). This has now be clarified in the docs: http://de3.php.net/hex2bin
If you wish so, I will revert the change. But I will spend no more time discussing this. I already
spent several hours in discussions about this rather unimportant issue.
Thanks,
Nikita.
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[2012-04-26 21:06:23] stas@php.net
I do not think BC break in 5.4 is a good idea.
------------------------------------------------------------------------
[2012-04-11 06:13:50] theanomaly dot is at gmail dot com
The patch currently in master still leaves a remanent problem. First,
var_dump(hex2bin('')) still returns string(0) "". Whether or not this is
acceptable is arguable. Since 0x00 is null, but an empty string isn't really
null.
For example:
var_dump(unpack('H*',hex2bin(''))); // will give me string(0) ""
Whereas:
var_dump(unpack('H*',hex2bin('00'))); // will give me string(2) ""
and:
var_dump(hex2bin('00')); // will give me string(1) "" # which is what I expect
So the warning needs to be amended for an empty string as well as odd-sized hex.
Additionally, the function now returns a bool(false), breaking BC.
I suggest a second optional argument to return partial binary (potentially
broken binary) even on error in the event the user wants to maintain backwards
compatibility. I'll be happy to submit another patch for this if there are no
objections.
------------------------------------------------------------------------
[2012-04-08 20:51:36] nikic@php.net
After some further discussion on IRC we agreed that it is best to throw a warning. The reasoning is
as outlined in my previous comment.
The warning is implemented with https://github.com/php/php-src/commit/7ae93a2c4c8a51cc2aec9977ce3c83c100e382a0.
------------------------------------------------------------------------
[2012-04-08 20:45:41] nikic@php.net
Automatic comment on behalf of nikic
Revision: http://git.php.net/?p=php-src.git;a=commit;h=7ae93a2c4c8a51cc2aec9977ce3c83c100e382a0
Log: Fix bug #61660: bin2hex(hex2bin($data)) != $data
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