NIX_STATE_HOME: unbound variable

[edolstra]

Describe the bug

Nix's bash profile script is failing on several platforms: https://hydra.nixos.org/eval/1808904#tabs-still-fail, e.g. https://hydra.nixos.org/build/272876158#tabs-summary:

/home/vagrant/.nix-profile/etc/profile.d/nix.sh: line 6: NIX_STATE_HOME: unbound variable

This was introduced in #11351 (ping @noamraph).

Steps To Reproduce

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior

A clear and concise description of what you expected to happen.

nix-env --version output

Additional context

Add any other context about the problem here.

Priorities

Add 👍 to issues you find important.

[noamraph]

Hi, sorry for the regression. The problem seems to be that I used if [ -n "$NIX_STATE_HOME" ] instead of if [ -n "${NIX_STATE_HOME-}" ]. I also changed the conditions at the beginning of the file to this form, as they would probably have caused the same issue if $HOME or $USER weren't defined.