default env vars

[retr0h]

I'm trying to understand how to use default and env together. I thought I might get fancy and simply add another variable with the value of env. However, if env fails to find the env var, it must return an empty string or something, b/c NEW_VERSION is always empty, unless command is prefixed with VERSION=foo.

I am sure I am going about this completely wrong, but was hoping to override VERSION similar to Make's FOO:=bar.

VERSION:
  sh: git describe --tags --always
SET_VERSION: '{{ env "VERSION" }}'
NEW_VERSION: '{{ default .VERSION .SET_VERSION }}'