This is an issue of composer as well: https://github.com/composer/composer/issues/4628 . It is the well-known Windows Long path Issue that can be fixed.

Note: Most file systems support up to 255 chars for file names. Path length are unlimited mostly.

https://en.wikipedia.org/wiki/Comparison_of_file_systems

I think we have the following limitation of Windows: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath . This has been a discussion for .NET as well: https://github.com/dotnet/corefx/issues/645

I have the same problem on Windows Server 2008, php 5.6.16

I confirm the problem and investigated which filesystem functions work with different lengths of filenames. In theory filesnames up to 259 length should work on Windows as it is below the 260 MAX_PATH length (including terminating null char). I could find out that some functions work with length 259 (touch, rename, file_exists etc), while other functions fail (copy, fopen, realpath, file_put_contents) for the same filename. So for these functions PHP does seem to do something inconsistently in a bad way which causes hard to debug problems.


Test script:
------------
<?php

$tmpDir = sys_get_temp_dir() . DIRECTORY_SEPARATOR;
$tmpDirLen = strlen($tmpDir);

foreach (array(258, 259, 260) as $fileLen) {
    $filename = $tmpDir . str_repeat('a', $fileLen - $tmpDirLen);
    var_dump($filename);

    echo 'touch: ';
    var_dump(@touch($filename));

    echo 'chmod: ';
    var_dump(@chmod($filename, 0666));

    echo 'file_exists: ';
    var_dump(file_exists($filename));

    echo 'is_file: ';
    var_dump(is_file($filename));

    echo 'stat: ';
    var_dump(@stat($filename) ? true : false);

    echo 'realpath: ';
    var_dump(realpath($filename) ? true : false);

    echo 'fopen: ';
    var_dump(($handle = @fopen($filename, 'r')) ? true : false);

    if ($handle) {
        fclose($handle);
    }

    echo 'unlink: ';
    var_dump(@unlink($filename));

    $tmpFile = tempnam(sys_get_temp_dir(), 'tmp');

    echo 'copy: ';
    var_dump(@copy($tmpFile, $filename));

    echo 'file_put_contents: ';
    var_dump(@file_put_contents($filename, 'test data') ? true : false);

    echo 'rename: ';
    var_dump($rename = @rename($tmpFile, $filename));

    unlink($rename ? $filename : $tmpFile);

    echo "\n\n";
}


Expected result:
----------------

string(258) "..."
touch: bool(true)
chmod: bool(true)
file_exists: bool(true)
is_file: bool(true)
stat: bool(true)
realpath: bool(true)
fopen: bool(true)
unlink: bool(true)
copy: bool(true)
file_put_contents: bool(true)
rename: bool(true)


string(259) "..."
touch: bool(true)
chmod: bool(true)
file_exists: bool(true)
is_file: bool(true)
stat: bool(true)
realpath: bool(true)
fopen: bool(true)
unlink: bool(true)
copy: bool(true)
file_put_contents: bool(true)
rename: bool(true)


string(260) "..."
touch: bool(false)
chmod: bool(false)
file_exists: bool(false)
is_file: bool(false)
stat: bool(false)
realpath: bool(false)
fopen: bool(false)
unlink: bool(false)
copy: bool(false)
file_put_contents: bool(false)
rename: bool(false)


Actual result:
--------------

string(258) "..."
touch: bool(true)
chmod: bool(true)
file_exists: bool(true)
is_file: bool(true)
stat: bool(true)
realpath: bool(true)
fopen: bool(true)
unlink: bool(true)
copy: bool(true)
file_put_contents: bool(true)
rename: bool(true)


string(259) "..."
touch: bool(true)
chmod: bool(true)
file_exists: bool(true)
is_file: bool(true)
stat: bool(true)
realpath: bool(false)
fopen: bool(false)
unlink: bool(true)
copy: bool(false)
file_put_contents: bool(false)
rename: bool(true)


string(260) "..."
touch: bool(false)
chmod: bool(false)
file_exists: bool(false)
is_file: bool(false)
stat: bool(false)
realpath: bool(false)
fopen: bool(false)
unlink: bool(false)
copy: bool(false)
file_put_contents: bool(false)
rename: bool(false)

I'm wondering if this is more a request than a bug. The current behaviour is not wrong per se, it's just a limitation of the specific Windows APIs in use.

I think it's a bug because, as noted by webmaster at tubo-world dot de, for files with a path of 259 characters, there is an inconsistent behaviour among different php file functions. Some support it and some don't.
Anyway, path lengths of 259 characters (260, including null terminator) should be supported on Windows, as they are within the allowed maximum path length.

Based on https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396 it seems that prepending the path with '\\?\' should fix it. But it does not seem to write through PHP.

Fixed in PHP 7.1

Thanks.