• Version: v8.4.0
• Platform: Windows 10
• Subsystem: git for Windows bash

The problem does not occur when node is started from a Windows shell - so it may be a git bash bug in the end?

Originally reported as flow-upgrade issue: facebook/flow#4647 (comment)

Code taken from https://nodejs.org/dist/latest-v8.x/docs/api/fs.html#fs_fs_mkdtemp_prefix_options_callback

fs.mkdtemp('/tmp/foo-', (err, folder) => {
  if (err) throw err;
  console.log(folder);
  // Prints: /tmp/foo-itXde2
});

When I run this from the node console started in the git for Windows bash I get

> fs.mkdtemp('/tmp/foo-', (err, folder) => {
...   if (err) throw err;
...   console.log(folder);
...   // Prints: /tmp/foo-itXde2
... });
undefined
> Error: ENOENT: no such file or directory, mkdtemp '/tmp/foo-XXXXXX'

/tmp exists and is accessible and writable, I can run mkdir /tmp/foo _from the bash command line.

The problem becomes visible in the full error message:

> { Error: ENOENT: no such file or directory, mkdir 'C:\tmp\FOO'
  errno: -4058,
  code: 'ENOENT',
  syscall: 'mkdir',
  path: 'C:\\tmp\\FOO' }

Highlight: path: 'C:\\tmp\\FOO'