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Date: Mon, 30 Oct 2017 15:05:30 +0800
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To: Derick Rethans <derick@php.net>
Cc: Dmitry Stogov <dmitry@zend.com>, Nikita Popov <nikita.ppv@gmail.com>, 
	PHP Developers Mailing List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="001a114d6dbcc8b572055cbe44e7"
Subject: Re: [PHP-DEV] Weird PHP 7.2 bug
From: laruence@php.net (Xinchen Hui)

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Hey:

On Mon, Oct 30, 2017 at 2:48 AM, Derick Rethans <derick@php.net> wrote:

> Hi,
>
> running:
> https://raw.githubusercontent.com/xdebug/xdebug/master/tests/bug01263.inc
>
> with:
> $ php -n -dzend_extension=opcache.so -dopcache.enable_cli=1
> tests/bug01263.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 $uncoveredFiles
are IS_UNDEF for sure(thus the foreach block actually won't be executed),

then in typeinfo inference system, we will get $uncoveredFile with type
info 0.

then later while doing type inference for ZEND_FETCH_W
($data[$uncoveredFile][$i]
= ), 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_ARRAY_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
trust def info, not use info...

so, I propose fix this by:
https://gist.github.com/laruence/9990ce5f9f3b30dd98dbff4f59109232

Dmitry, what do you think?

thanks

>
>
> cheers,
> Derick
>
> --
> https://derickrethans.nl | https://xdebug.org | https://dram.io
> Like Xdebug? Consider a donation: https://xdebug.org/donate.php
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>
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>



-- 
Xinchen Hui
@Laruence
http://www.laruence.com/

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