Issue: https://github.com/php/php-src/issues/11941
Author: mikhainin
### Description
I'm not sure if it's the bug or a feature request.
Basically, I found the problem in
[ext/soap/tests/server009.phpt](https://github.com/php/php-src/blob/4a77a1ec08cd42745abc9f1d34c0ee36c9fea405/ext/soap/tests/server009.phpt#L7)
```php
class foo {
private $sum = 0;
function Sum($num) {
return $this->sum += $num;
}
}
$server = new soapserver(null,array('uri'=>"http://testuri.org"));
$server->setclass("foo");
$server->setpersistence(SOAP_PERSISTENCE_SESSION);
```
When we use SOAP_PERSISTENCE_SESSION, it will silently fail if **session** is built as
a shared library. It may be a common case for distribution - they tend to offer extensions
separately from the language core.
The check for this value is protected by guards
([link](https://github.com/php/php-src/blob/4a77a1ec08cd42745abc9f1d34c0ee36c9fea405/ext/soap/soap.c#L1346))
```c
#if defined(HAVE_PHP_SESSION) && !defined(COMPILE_DL_SESSION)
/* If session then update session hash with new object */
if (service->soap_class.persistence == SOAP_PERSISTENCE_SESSION) {
zval *session_vars = &PS(http_session_vars), *tmp_soap_p;
...
} else {
soap_obj = &tmp_soap;
}
#else
```
I'm not sure what is the best way to improve this, we can probably:
- make sure that **session.so** is loaded when we use the feature
- throw an exception when setPersistence is called with an impossible argument
- trigger a warning telling the user that this not gonna work
I reckon, at least we should raise the warning - otherwise it may be quite confusing for the user