Internal stream casting should not emit lost bytes warning twice

[Girgias]

Description

The following code:

<?php
$handle = fopen('http://example.com', 'r');
var_dump(stream_isatty($handle));

Resulted in this output:

Warning: stream_isatty(): 1256 bytes of buffered data lost during stream conversion! in test.php on line 3

Warning: stream_isatty(): 1256 bytes of buffered data lost during stream conversion! in test.php on line 3
bool(false)

But I expected this output instead:

Warning: stream_isatty(): 1256 bytes of buffered data lost during stream conversion! in test.php on line 3
bool(false)

Or ideally:

bool(false)

The thing is that if one reads the original stream via:

$contents = '';
while (!feof($handle)) {
    $contents .= fread($handle, 8192);
}
var_dump($contents);

One does get the totality of the 1256 bytes of output.
So I'm confused as to why the warning is emitted in the first place.

PHP Version

master

Operating System

No response

[Girgias]

Okay, I have figured why the warning is emitted twice. This warning is not gated by a if (show_err) { clause.

[danepowell]

I'm a little lost trying to follow the conversation in #10093 and #10173. As an end user of functions like stream_isatty and posix_isatty, I feel like they should never emit such a warning. Who cares what data is lost in conversion as long as the function returns the correct result? How am I supposed to respond to such a warning?

I think either the warning should be suppressed, or guidance should be provided on how to resolve it.

[Girgias]

#10173 would fix the warning being displayed, because it indeed makes no sense to display it.

[Girgias]

Fixed via #10173 and the follow-up commits

[danepowell]

I opened a PR to backport this fix to PHP 8.2 but it hasn't gotten any traction, is there some other process to backport this fix? #13821