Good idea, confirmed as follows:

mkdir foo
TMPDIR=./foo nvim
:echo tempname()
!rm -r foo
:echo tempname()

tempname() still uses the foo path even though it was deleted, so any plugin using tempname() will break. I wonder why this check wasn't done...

tempname() still uses the foo path even though it was deleted, so any plugin using tempname() will break. I wonder why this check wasn't done...

For performance reasons. I did suggest doing something like this years ago, but Bram did not want to check for the existence of the path everytime a temp path was created. Rather it was pointed out, that the temporary directory should not be removed (and the system is brocken).

Some more information.

See here:
https://groups.google.com/d/msg/vim_use/qgRob9SWDv8/FAOFVVcDTv0J
(I use the provided command Mktempdir)

and here for my old patch:
https://groups.google.com/d/msg/vim_dev/cogp-Vye4oo/d_SVFXBbnnoJ

Thanks @chrisbra !

did not want to check for the existence of the path everytime a temp path was created

I would guess creating a file is far more expensive than os_isdir, so avoiding os_isdir gains relatively little.

I agree that a temp dir going missing is indicative of a broken system, so we should (also) show an error . Something like this:

  if (vim_tempdir == NULL || !os_isdir(vim_tempdir)) {
    if (vim_tempdir != NULL) {
      emsgf("EXX: tempdir went missing (antivirus or misconfigured cleanup job?)");
      XFREE_CLEAR(vim_tempdir);
    }
    vim_maketempdir();
  }

If you are re-creating the temp directory, why bothering with an error message?

Because such a system is likely in a bad state and even after creating the directory, some plugins are likely broken.

This will close #1432

@erw7 Any issues with adding the error message?

Any issues with adding the error message?

Yes, I think we should add an error message as well. I think the reason I didn't add the error message is because I didn't know how to assign EXX.