Using stream wrappers breaks proc_open

Description

The following code (from https://packagist.org/packages/dg/bypass-finals, which is where the issue is happening):

<?php

class Wrapper {
	/** @var resource|null  Stream context, which may be set by stream functions */
	public $context;

	/** @var resource|null  File handle, which may be set by stream functions */
	public $handle;


	public function dir_closedir(): void
	{
		closedir($this->handle);
	}


	public function dir_opendir(string $path, int $options): bool
	{
		$this->handle = $this->context
			? $this->native('opendir', $path, $this->context)
			: $this->native('opendir', $path);
		return (bool) $this->handle;
	}


	public function dir_readdir()
	{
		return readdir($this->handle);
	}


	public function dir_rewinddir(): bool
	{
		rewinddir($this->handle);
		return true;
	}


	public function mkdir(string $path, int $mode, int $options): bool
	{
		$recursive = (bool) ($options & STREAM_MKDIR_RECURSIVE);
		return $this->context
			? $this->native('mkdir', $path, $mode, $recursive, $this->context)
			: $this->native('mkdir', $path, $mode, $recursive);
	}


	public function rename(string $pathFrom, string $pathTo): bool
	{
		return $this->context
			? $this->native('rename', $pathFrom, $pathTo, $this->context)
			: $this->native('rename', $pathFrom, $pathTo);
	}


	public function rmdir(string $path, int $options): bool
	{
		return $this->context
			? $this->native('rmdir', $path, $this->context)
			: $this->native('rmdir', $path);
	}


	public function stream_cast(int $castAs)
	{
		return $this->handle;
	}


	public function stream_close(): void
	{
		fclose($this->handle);
	}


	public function stream_eof(): bool
	{
		return feof($this->handle);
	}


	public function stream_flush(): bool
	{
		return fflush($this->handle);
	}


	public function stream_lock(int $operation): bool
	{
		return $operation
			? flock($this->handle, $operation)
			: true;
	}


	public function stream_metadata(string $path, int $option, $value): bool
	{
		switch ($option) {
			case STREAM_META_TOUCH:
				return $this->native('touch', $path, $value[0] ?? time(), $value[1] ?? time());
			case STREAM_META_OWNER_NAME:
			case STREAM_META_OWNER:
				return $this->native('chown', $path, $value);
			case STREAM_META_GROUP_NAME:
			case STREAM_META_GROUP:
				return $this->native('chgrp', $path, $value);
			case STREAM_META_ACCESS:
				return $this->native('chmod', $path, $value);
			default:
				return false;
		}
	}


	public function stream_open(string $path, string $mode, int $options = 0, ?string &$openedPath = null): bool
	{
		$usePath = (bool) ($options & STREAM_USE_PATH);
		$this->handle = $this->context
			? $this->native('fopen', $path, $mode, $usePath, $this->context)
			: $this->native('fopen', $path, $mode, $usePath);
		return (bool) $this->handle;
	}


	public function stream_read(int $count)
	{
		return fread($this->handle, $count);
	}


	public function stream_seek(int $offset, int $whence = SEEK_SET): bool
	{
		if (stream_get_meta_data($this->handle)['seekable']) {
			return fseek($this->handle, $offset, $whence) === 0;
		}
		return false;
	}


	public function stream_set_option(int $option, int $arg1, ?int $arg2)
	{
		switch ($option) {
			case STREAM_OPTION_BLOCKING:
				return stream_set_blocking($this->handle, (bool) $arg1);
			case STREAM_OPTION_READ_BUFFER:
				return stream_set_read_buffer($this->handle, $arg2);
			case STREAM_OPTION_WRITE_BUFFER:
				return stream_set_write_buffer($this->handle, $arg2);
			case STREAM_OPTION_READ_TIMEOUT:
				return stream_set_timeout($this->handle, $arg1, $arg2);
			default:
				return false;
		}
	}


	public function stream_stat()
	{
		return fstat($this->handle);
	}


	public function stream_tell()
	{
		return ftell($this->handle);
	}


	public function stream_truncate(int $newSize): bool
	{
		return ftruncate($this->handle, $newSize);
	}


	public function stream_write(string $data)
	{
		return fwrite($this->handle, $data);
	}


	public function unlink(string $path): bool
	{
		return $this->native('unlink', $path);
	}


	public function url_stat(string $path, int $flags)
	{
		if ($flags & STREAM_URL_STAT_QUIET) {
			set_error_handler(function () {
				return true;
			});
		}
		try {
			$func = $flags & STREAM_URL_STAT_LINK ? 'lstat' : 'stat';
			return $this->native($func, $path);
		} catch (\RuntimeException $e) {
			// SplFileInfo::isFile throws exception
			return false;
		} finally {
			if ($flags & STREAM_URL_STAT_QUIET) {
				restore_error_handler();
			}
		}
	}


	/**
	 * Temporarily restores the native protocol handler to perform operations.
	 */
	private function native(string $func)
	{
		stream_wrapper_restore('file');
		try {
			return $func(...array_slice(func_get_args(), 1));
		} finally {
			stream_wrapper_unregister('file');
			stream_wrapper_register('file', self::class);
		}
	}
}

stream_wrapper_unregister('file');
stream_wrapper_register('file', Wrapper::class);

$proc = \proc_open(
	'/usr/bin/ls',
	[["file", "/dev/null", "r"], STDOUT, STDERR],
	$pipes,
);

Resulted in this output:

Warning: proc_open(): posix_spawn() failed: Bad file descriptor in /Users/daniil/repos/php-src/a.php on line 226

But I expected this output instead: No error.

Stepping through the code, it seems strange to me that this would fail, as after stream_cast returns the real underlying stream resource, it is then re-passed to _php_stream_cast, behaving just like as if no stream wrapper is in use.

Another issue is the fact that stream_cast is even part of the stream wrapper API in the first place, given that its only real function is to return the inner resource (regardless of the cast type); a get_inner_resource method would've been way less confusing...

PHP Version

PHP 8.4.4

Operating System

Ubuntu 24.04

Start with the PHP reproduction in a.php and trace proc_open through stream_cast and _php_stream_cast, focusing on the supplied stream-wrapper setup and the posix_spawn Bad file descriptor result. Reproduce it on PHP 8.4.4 with /usr/bin/ls; done means proc_open completes without the warning when the wrapper is active.