test-case.sh

nvm_version_greater() {
  command awk 'BEGIN {
    if (ARGV[1] == "" || ARGV[2] == "") exit(1)
    split(ARGV[1], a, /\./);
    split(ARGV[2], b, /\./);
    for (i=1; i<=3; i++) {
      if (a[i] && a[i] !~ /^[0-9]+$/) exit(2);
      if (b[i] && b[i] !~ /^[0-9]+$/) { exit(0); }
      if (a[i] < b[i]) exit(3);
      else if (a[i] > b[i]) exit(0);
    }
    exit(4)
  }' "${1#v}" "${2#v}"
}

set -e
if nvm_version_greater 0.12.0 0.12.87; then echo y; else echo n; fi

bash/sh on my mac exits with 3; zsh and dash properly echo 'n'. Any idea what's going on?

Turns out it's a bug in bash 3.2, fixed in 4.4: bats-core/bats-core#72 (comment) and https://tiswww.case.edu/php/chet/bash/CHANGES