Parse_str(string,array) semantics

[zhangmuhua]

i use function parse_str to parse url, but fail with hhvm.

1. code as follows:
   1

2. php interpreter print as follows:
   23
   John Adams

3. but hhvm interpreter print as follows:
   HipHop Notice: Undefined variable: id in */test/test_parse_str.php on line 4

HipHop Notice: Undefined variable: name in */test/test_parse_str.php on line 6

who can help me? how can i use this function in hhvm?

[zhangmuhua]

i watched the implementation in hhvm:
989 void f_parse_str(CStrRef str, VRefParam arr /* = null */) {
990 arr = Array::Create();
991 HttpProtocol::DecodeParameters(arr, str.data(), str.size());
992 }

[javer]

You should build HHVM from source using master HEAD, because this issue was fixed 22 days ago in #1063.

[zhangmuhua]

very thx, @javer

[zhangmuhua]

1)resolved this problem with new version.
2)but there still a bug.
for example：
1

$name is undefined in hhvm.

[javer]

It is the same as in PHP. Look at PHP manual http://php.net/manual/en/function.parse-str.php:

Parses str as if it were the query string passed via a URL and sets variables in the current scope.
If the second parameter arr is present, variables are stored in this variable as array elements instead.

[huzhiguang]

@javer ,I have fixed @zhangmuhua 's problem.
This code as follow:

  void f_parse_str(CStrRef str, VRefParam arr /* = null */) {
  Variant result;
    HttpProtocol::DecodeParameters(result, str.data(), str.size());
    if(!arr.isReferenced()) {
            f_extract(result.toArray());
            return;
    }
   ///////////////////////////////fixed notice variable undefined  //////////////////////////
    Array vars=result.toArray();
    Array newVars=Array::Create();
    for (ArrayIter iter(vars); iter; ++iter) {
            Variant key = iter.first();
            Variant value;
            value.setNull();
            newVars.set(key,Variant(value));
    }
    f_extract(newVars);
   ///////////////////////////////////////////////////////////////////////////////
    arr = result.toArray();
   }

I will pull request hiphop-php master.^_^

[javer]

@huzhiguang, not sure if it should be fixed, because PHP and HHVM results is the same.

test.php:

<?php
error_reporting(E_ALL);
parse_str("id=23&name=John%20Adams", $a);
print_r($a);
echo $name . "\n";

PHP:

$ php -n test.php
Array
(
    [id] => 23
    [name] => John Adams
)

Notice: Undefined variable: name in test.php on line 5

HHVM:

$ hhvm test.php
Array
(
    [id] => 23
    [name] => John Adams
)
HipHop Notice: Undefined variable: name in test.php on line 5

In your patch you can overwrite previously defined variables, check this test:

<?php
$name = 'Smith';
parse_str("id=23&name=John%20Adams", $a);
echo $name . "\n";

And it will be undocumented behavior because according to PHP manual when second parameter is given no variables should be extracted.

[huzhiguang]

I have fixed this problem, you can try it,do you see any other questions?

fixed code as follow:

  void f_parse_str(CStrRef str, VRefParam arr /* = null */) {
   Variant result;

    HttpProtocol::DecodeParameters(result, str.data(), str.size());

    if(!arr.isReferenced()) {
            f_extract(result.toArray());
            return;
    }
    ///////////////////////////////fixed notice variable undefined  //////////////////////////
    Array vars=result.toArray();
    Array newVars=Array::Create();
    Array allVars=f_get_defined_vars();
    for (ArrayIter iter(vars); iter; ++iter) {
            Variant key = iter.first();
            if(!allVars.exists(key)){
                    Variant value;
                    value.setNull();
                    newVars.set(key,Variant(value));
            }
    }
    f_extract(newVars);
      ///////////////////////////////////////////////////////////////////////////////
    arr = result.toArray();
    }

[javer]

@huzhiguang, compare output of this script on PHP and your patched HHVM:

<?php
parse_str("id=23&name=John%20Adams", $a);
var_dump(isset($name));

PHP Output:

bool(false)

As I said before, this is because no variables should be extracted when second parameter of parse_str is given. See https://github.com/php/php-src/blob/master/ext/standard/string.c#L4454-4460 for details.

[scannell]

Thanks @javer.

@zhangmuhua, we're not going to make this work when Zend doesn't -- I suggest you take it up with them if you want the behavior of the language to be changed in 5.6 or 5.7, then we'll consider fixing it.

[huzhiguang]

ok,@javer,I have looked at the zend implementation logic, arrayArg !=NULL parse variable don't use zend_rebuild_symbol_table,so variable do not exist,I have understanded.thanks,you provide way is true,although the notice problems.