Merge pull request #2194 from grahamc/nix-profile-daemon-profile-set-u

Nix profile & installation: handle set -u installations

scripts/install-multi-user.sh

@@ -727,7 +727,7 @@ setup_default_profile() {
     _sudo "to installing a bootstrapping Nix in to the default Profile" \
           HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_NIX"
 
-    if [ -z "$NIX_SSL_CERT_FILE" ] || ! [ -f "$NIX_SSL_CERT_FILE" ]; then
+    if [ -z "${NIX_SSL_CERT_FILE:-}" ] || ! [ -f "${NIX_SSL_CERT_FILE:-}" ]; then
         _sudo "to installing a bootstrapping SSL certificate just for Nix in to the default Profile" \
               HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_CACERT"
         export NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt

scripts/nix-profile-daemon.sh.in

 # Only execute this file once per shell.
-if [ -n "$__ETC_PROFILE_NIX_SOURCED" ]; then return; fi
+if [ -n "${__ETC_PROFILE_NIX_SOURCED:-}" ]; then return; fi
 __ETC_PROFILE_NIX_SOURCED=1
 
 # Set up secure multi-user builds: non-root users build through the
@@ -51,7 +51,7 @@ fi
 
 
 # Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
-if [ ! -z "$NIX_SSL_CERT_FILE" ]; then
+if [ ! -z "${NIX_SSL_CERT_FILE:-}" ]; then
     : # Allow users to override the NIX_SSL_CERT_FILE
 elif [ -e /etc/ssl/certs/ca-certificates.crt ]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
     export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt