stream_get_meta_data returns an empty uri for tmpfile() streams

[stof]

The assetic testsuite is currently failing 1 test on HHVM on Travis: https://travis-ci.org/kriswallsmith/assetic/jobs/22333581
When looking at the failure, I see that the command being executed has an empty argument for the --flagfile option. In the test, this option is set by getting the uri of a tmp file with stream_get_meta_data. It looks like it returns an empty string in the uri key instead of returning the path to the file created by tmpfile.

the code of the test is https://github.com/kriswallsmith/assetic/blob/master/tests/Assetic/Test/Filter/GoogleClosure/CompilerJarFilterTest.php#L105-112

[fredemmott]

Simpler test case:

<?php
$f = tmpfile();
var_dump(stream_get_meta_data($f)['uri']);

[fredemmott]

This isn't quite as trivial as it sounds - we use the c tmpfile() call which gives us an fd, not a filename. This is better ins ome ways (it removes a race condition), but makes it hard to implement this.

[LiraNuna]

It's possible but that will only work on Linux, using fcntl and F_GETPATH.

[sgolemon]

Yeah, tmpfile() resources don't necessarily have paths. On linux this seems to be commonly implemented by creating a file and immediately unlinking it (meaning the open file handle is the only reference to it), it literally doesn't have an entry on the file system. If you need a file path you really should use tempnam() and open/close/unlink the file explicitly.

You could do something like the following (untested):

function tmpfilewithname(&$name, $prefix = '') {
  $name = tempnam(sys_get_tmp_dir(), $prefix);
  $fp = fopen($name, 'w+');
  register_shutdown_function(function() use ($fp, $name) {
    fclose($fp);
    unlink($name);
  });
  return $fp;
}