Exception on two dimensional array assignment

[TianBo-Timothy]

I am having a problem when assigning a value to a two-dimensional array while writing a PHP extension with PHPCPP library.

The extension works fine with PHPCPP5 + PHP5, but fails with PHPCPP7 + PHP7 (both on ubuntu 16.04). When works with PHPCPP7, I get a fatal error with message:

PHP Fatal error: Cannot make a variable undefined in /path/to/my/php/code.php

The function in the extension looks like:

Php::Value foo(Php::Parameters & params)
{
    Php::Value test;
    test[2][0] = 100;
    return test;
}

I tried to change Php::Value to Php::Array, the same error is produced. If I change test[2][0] = 100; to test["a"][0] = 100;, then there is no error. However, this is not what I want.

The stack trace is as follows:

-- stack trace --
  /path/to/my/extension.so : Php::Value::setType(Php::Type) &+0x182
  /path/to/my/extension.so : Php::Value::Value(Php::Type)+0x30
  /path/to/my/extension.so : Php::Value::get(int) const+0x73
  /path/to/my/extension.so : Php::HashMember<int>::value() const+0x49
  /path/to/my/extension.so : Php::HashMember<int>::set(int, Php::Value const&)+0x36
  /path/to/my/extension.so : Php::HashMember<int>::operator=(Php::Value const&)+0x3a
  /path/to/my/extension.so : foo(Php::Parameters&)+0x95
  /path/to/my/extension.so : void Php::ZendCallable::invoke<&(foo(Php::Parameters&))>(_zend_execute_data*, _zval_struct*)+0x66
  php : ()+0x2e1456
  php : execute_ex()+0x1b

I am not sure if it is due to a newly introduced bug or there is a mistake I made in my code, please have a look. Thanks!

[TianBo-Timothy]

To those who are having the same problem, the following workaround works:

Php::Value foo(Php::Parameters & params)
{
    Php::Value test;
    Php::Array v;
    v[0] = 100;
    test[2] = v;
    return test;
}