SplFileObject::isReadable and SplFileObject::isWriteable provide an untrustworthy interface

Description

isReadable and isWriteable only consider the file system permissions but that isn't actually reflective of the state of the object because read and write methods also consider the resource mode so if you trust them you can can run into unexpected bugs as demonstrated in the example below.

Specifically
1 . Streams don't look readable?
2. Resources that are opened write only look readable.

The following code:

<?php

function showFile(\SplFileObject $file) {
    var_dump($file->isReadable());
    if ($file->isReadable()) {
      var_dump($file->fread($file->getSize()));
    }
    echo str_repeat('=', 80) . PHP_EOL;
}

showFile(new SplFileObject(__FILE__));
$f = new SplFileObject('php://temp', 'r+');
$f->fwrite('content');
showFile($f);
showFile(new SplFileObject(__FILE__, 'a'));

Resulted in this output:

bool(true)
string(376) "<?php

function showFile(\SplFileObject $file) {
    var_dump($file->isReadable());
    if ($file->isReadable()) {
      var_dump($file->fread($file->getSize()));
    }
    echo str_repeat('=', 80) . PHP_EOL;
}

showFile(new SplFileObject(__FILE__));
$f = new SplFileObject('php://temp', 'r+');
$f->fwrite('content');
showFile($f);
showFile(new SplFileObject(__FILE__, 'a'));
"
================================================================================
bool(false)
================================================================================
bool(true)
PHP Notice:  SplFileObject::fread(): Read of 8192 bytes failed with errno=9 Bad file descriptor in /tmp/tmp.php on line 6
bool(false)
================================================================================

But I expected this output instead:

bool(true)
string(376) "<?php

function showFile(\SplFileObject $file) {
    var_dump($file->isReadable());
    if ($file->isReadable()) {
      var_dump($file->fread($file->getSize()));
    }
    echo str_repeat('=', 80) . PHP_EOL;
}

showFile(new SplFileObject(__FILE__));
$f = new SplFileObject('php://temp', 'r+');
$f->fwrite('content');
showFile($f);
showFile(new SplFileObject(__FILE__, 'a'));
"
================================================================================
bool(true)
string(7) "content"
================================================================================
bool(false)

PHP Version

all

Operating System

No response

Các điểm đầu vào là SplFileObject::isReadable(), SplFileObject::isWriteable() và các phương thức đọc/ghi được minh họa trong ví dụ. Trước tiên, hãy theo dõi cách các phương thức này đánh giá quyền của hệ thống tệp so với chế độ tài nguyên. Thêm phạm vi kiểm thử hồi quy cho các trường hợp r+, chỉ ghi và nối thêm, sau đó xác minh các đầu ra được báo cáo và mong đợi.