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To: Xinchen Hui <laruence@php.net>, Derick Rethans <derick@php.net>
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Thread-Topic: [PHP-DEV] Weird PHP 7.2 bug
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Date: Mon, 30 Oct 2017 07:55:46 +0000
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Subject: Re: [PHP-DEV] Weird PHP 7.2 bug
From: dmitry@zend.com (Dmitry Stogov)

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Fixed. thanks. for catching.

The real problem - incorrect handling of "wrong index type.

In this situation PHP should keep input array unchanged.


Inferring types "by usage" makes sense (for array)

e.g. $a[$n]++ should change the type of array.


Thanks. Dmitry.


________________________________
From: Xinchen Hui <laruence@php.net>
Sent: Monday, October 30, 2017 10:05:30 AM
To: Derick Rethans
Cc: Dmitry Stogov; Nikita Popov; PHP Developers Mailing List
Subject: Re: [PHP-DEV] Weird PHP 7.2 bug

Hey:

On Mon, Oct 30, 2017 at 2:48 AM, Derick Rethans <derick@php.net<mailto:deri=
ck@php.net>> wrote:
Hi,

running:
https://raw.githubusercontent.com/xdebug/xdebug/master/tests/bug01263.inc

with:
$ php -n -dzend_extension=3Dopcache.so -dopcache.enable_cli=3D1 tests/bug01=
263.inc

Produces the following output with PHP 7.2 build at Oct 29 2017 18:49:58:

In function PHP_CodeCoverage::addUncoveredFilesFromWhitelist (after sccp):
var 10 (CV $data) has array value type but not key type
var 15 (CV $data) has array value type but not key type
var 21 (CV $data) has array value type but not key type

In function PHP_CodeCoverage::addUncoveredFilesFromWhitelist (after calls):
var 10 (CV $data) has array value type but not key type
var 15 (CV $data) has array value type but not key type
var 21 (CV $data) has array value type but not key type

In function PHP_CodeCoverage::addUncoveredFilesFromWhitelist (after dce):
var 10 (CV $data) has array value type but not key type
var 15 (CV $data) has array value type but not key type
var 21 (CV $data) has array value type but not key type

In function PHP_CodeCoverage::addUncoveredFilesFromWhitelist (after dfa):
var 10 (CV $data) has array value type but not key type
var 15 (CV $data) has array value type but not key type
var 21 (CV $data) has array value type but not key type
First, this won't bring any harm to execution,  this is becuase  we know $u=
ncoveredFiles are IS_UNDEF for sure(thus the foreach block actually won't b=
e executed),

then in typeinfo inference system, we will get $uncoveredFile with type inf=
o 0.

then later while doing type inference for ZEND_FETCH_W ($data[$uncoveredFil=
e][$i] =3D ), since $unconveredFile has 0 type info, thus we won't get any =
key info of the array ($data),

but in the current type inference system, FETCH_W's result will be used in =
ASSIGN_DIM , then the system think $data maybe an array of array(MAY_BE_ARR=
AY_OF_ARRAY).

which result:  has array value type but not key type

anyway, I think infer type infos by usage is wrong here, we should only tru=
st def info, not use info...

so, I propose fix this by: https://gist.github.com/laruence/9990ce5f9f3b30d=
d98dbff4f59109232

Dmitry, what do you think?

thanks


cheers,
Derick

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Xinchen Hui
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