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Date: Sun, 05 Feb 2017 21:03:42 +0700
To: internals <internals@lists.php.net>
Cc: laruence@php.net
Message-ID: <48a7eb6950ea9a1f512937f138dd5fb9@andb.name>
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Subject: [PHP-DEV] Need help with strange and random bug
From: andrey@andb.name (Andrey E Baranov)

Hi all,

I have problem, debug is not yet finished, and for now do not can 
reproduce, problem occurs only in production (after migrate to PHP7). 
perhaps someone else can help :)
PHP 7.0.13 (Ubuntu 16.04 package repository), php-fpm

For simplify:
```
...
Log::debug('1:' . print_r($video, true));
Log::debug('2:' . json_encode($video) . ' json_last_error: ' . 
json_last_error() . ' json_last_error_msg: ' . json_last_error_msg());

$video['delivery'] = [2]; // after this line: serialize and json_encode 
do not work as expected

Log::debug('3:' . print_r($video, true));
Log::debug('4:' . serialize($video));
Log::debug('5:' . json_encode($video) . ' json_last_error: ' . 
json_last_error() . ' json_last_error_msg: ' . json_last_error_msg());
...
```

log with bug:
```
DEBUG: 1:Array
(
     [mimes] => Array
         (
             [0] => video/mp4
         )

     [linearity] => 1
     [minduration] => 5
     [maxduration] => 60
     [protocols] => Array
         (
             [0] => 2
             [1] => 3
         )

     [w] => 818
     [h] => 460
     [minbitrate] => 100
     [maxbitrate] => 1200
)
DEBUG: 2: 
{"mimes":["video/mp4"],"linearity":1,"minduration":5,"maxduration":60,"protocols":[2,3],"w":818,"h":460,"minbitrate":100,"maxbitrate":1200}
DEBUG: 3:Array
(
     [mimes] => Array
         (
             [0] => video/mp4
         )

     [linearity] => 1
     [minduration] => 5
     [maxduration] => 60
     [protocols] => Array
         (
             [0] => 2
             [1] => 3
         )

     [w] => 818
     [h] => 460
     [minbitrate] => 100
     [maxbitrate] => 1200
     [delivery] => Array
         (
             [0] => 2
         )

)
DEBUG: 
4:a:10:{s:5:"mimes";a:1:{i:0;s:9:"video/mp4";}s:9:"linearity";i:1;s:11:"minduration";i:5;s:11:"maxduration";i:60;s:9:"protocols";a:2:{i:0;i:2;i:1;i:3;}s:1:"w";i:818;s:1:"h";i:460;s:10:"minbitrate";i:100;s:10:"maxbitrate";i:1200;s:8:"delivery";N;}
DEBUG: 5: json_last_error: 6 json_last_error_msg: Recursion detected
```

- 4: `serialize($video)` - `"delivery";N;` - it is mean that `delivery` 
is Null - that is not true
- 5: `json_encode($video)` - Recursion detected

Problem occurs in random period after start fpm process (after 10..30 
min), and remains constant until restart fpm

Same problem as I see in 
http://stackoverflow.com/questions/37456845/what-does-json-error-recursion-mean-from-json-encode

After deep analyze:

php_json_encode_array:
```
```
if (myht && ZEND_HASH_GET_APPLY_COUNT(myht) > 1) {
   JSON_G(error_code) = PHP_JSON_ERROR_RECURSION;
   smart_str_appendl(buf, "null", 4);
   return;
}
```

serialize:
```
if (... || (Z_TYPE_P(data) == IS_ARRAY && 
Z_ARRVAL_P(data)->u.v.nApplyCount > 1)
   ) {
     smart_str_appendl(buf, "N;", 2);
...
```

so looks like problem in `HashTable.v.nApplyCount`


Also I am find commit - 
https://github.com/php/php-src/commit/d26ca894020bc28eb55b153fac5548374d5ce16d

In this commit added
```
target->u.flags = (source->u.flags & 
~(...|ZEND_HASH_APPLY_COUNT_MASK))...
```
But not added to case if `if (GC_FLAGS(source) & IS_ARRAY_IMMUTABLE)` - 
maybe need fix in this place? :) I guess that the problem in immutable 
arrays.

I do not have experience with PHP-SRC - and I could be wrong

thanks!