Question

I have a symlink on my Windows server which was made like this:

F:\>mkdir link-target
F:\>mklink /D link f:\link-target 

(Note the lower case f: in the symlink target)

In PHP I run this:

$dir = realpath('f:\link');
var_dump($dir);

$dir = realpath($dir);
var_dump($dir);

Which outputs:

string 'f:\link-target' (length=14)
string 'F:\link-target' (length=14)

Notice the change in case on the second realpath.

Is this a bug, or intended? And whats the best way to work around it?

It is breaking a case like this:

function check_link($to, $from) {
    if (realpath($to) !== realpath($from)) {
        ...
    }
}

Which is used to check $to exists, and is linked to $from.

• PHP 5.4
• Windows 7

Edit:

I need consistent behavior on both Windows and Linux, and have the following work around be its pretty nasty:

if (realpath($from) === false) {
} elseif (realpath($to) === false) {
} else {
    do {
        $to = realpath($to);
    } while (realpath($to) !== false && $to !== realpath($to));
    do {
        $from = realpath($from);
    } while (realpath($from) !== false && $from !== realpath($from));
    if ($to !== $from) {
        ...
    }
}

Edit 2:

On furter investigation I have noticed that on Windows symlinks are only followed 1 level deep:

// F:\>mkdir link-target
// F:\>mklink /D link f:\link-target 
// F:\>mklink /D link2 f:\link

$dir = realpath('f:\link2');
var_dump($dir);

$dir = realpath($dir);
var_dump($dir);

$dir = realpath($dir);
var_dump($dir);

// string 'f:\link' (length=7)
// string 'f:\link-target' (length=14)
// string 'F:\link-target' (length=14)

Answer 1

Turns out

do {
    $to = realpath($to);
} while (realpath($to) !== false && $to !== realpath($to));

is the only way.

https://bugs.php.net/bug.php?id=61933