Output Buffering: Add behavioural tests and some refactoring to ob_start()

[Girgias]

No description provided.

[SakiTakamachi]

Since optional arguments are parsed multiple times, why not receive $callback as a zval and then parse it?

edit:
Might be a bit annoying as the error order changes...

[Girgias]

Doing multiple argument parsing is not new and generally how we deal with overloaded signatures, and ideally the normal callback function should work (which is not the case for zlib) and actually exist (which is not the case for the iconv one)

[haszi]

Probably a copy-paste leftover as this test is about ob_start() throwing on a negative buffer size, right?

[haszi]

I think resources are converted to strings without raising a warning. Source ref (_convert_to_string()):

php-src/Zend/zend_operators.c

Lines 743 to 747 in 79c134a

	case IS_RESOURCE: {
	zend_string *str = zend_strpprintf(0, "Resource id #" ZEND_LONG_FMT, (zend_long)Z_RES_HANDLE_P(op));
	zval_ptr_dtor(op);
	ZVAL_NEW_STR(op, str);
	break;

[haszi]

This should probably read something like Errors in output handler are suppressed if handler does not return false as the following handler will return the undefined variable warning as well:

function handler(string $buffer, int $phase) {
    echo "In handler";
    // Undefined variable
    $undef++;
    
    return false;
}

[haszi]

I'm not sure whether it makes sense to add tests for these but during shutdown a handler returning an array or a fatal error being raised in a handler produce a slightly different output than what the existing tests show.

[haszi]

I think it would also make sense to add a basic test for what output is buffered and what is not. Something like https://3v4l.org/XoAGC

[Girgias]

I've seen the comments, just haven't had time.

I will add some more tests, namely to test shutdown