darwin-rebuild: fix sudo invocation on High Sierra

The version of sudo on macOS 10.13 High Sierra does not support the
`--preserve-env=LIST` option syntax, which is used here to preserve
PATH.

Override sudo with a shell function that checks for the availability of
this option syntax, and do not pass PATH otherwise.

Also move the prefix env command in the sudo invocations into the new
sudo function.

Signed-off-by: Rafael Kitover <[email protected]>

pkgs/nix-tools/darwin-rebuild.sh

@@ -16,6 +16,14 @@ showSyntax() {
   exit 1
 }
 
+sudo() {
+  if command sudo --help | grep -- --preserve-env= >/dev/null; then
+    command sudo -H --preserve-env=PATH env "$@"
+  else
+    command sudo -H "$@"
+  fi
+}
+
 # Parse the command line.
 origArgs=("$@")
 extraMetadataFlags=()
@@ -187,7 +195,7 @@ fi
 
 if [ "$action" = list ] || [ "$action" = rollback ]; then
   if [ "$USER" != root ] && [ ! -w $(dirname "$profile") ]; then
-    sudo -H --preserve-env=PATH env nix-env -p "$profile" "${extraProfileFlags[@]}"
+    sudo nix-env -p "$profile" "${extraProfileFlags[@]}"
   else
     nix-env -p "$profile" "${extraProfileFlags[@]}"
   fi
@@ -205,7 +213,7 @@ if [ -z "$systemConfig" ]; then exit 0; fi
 
 if [ "$action" = switch ]; then
   if [ "$USER" != root ] && [ ! -w $(dirname "$profile") ]; then
-    sudo -H --preserve-env=PATH env nix-env -p "$profile" --set "$systemConfig"
+    sudo nix-env -p "$profile" --set "$systemConfig"
   else
     nix-env -p "$profile" --set "$systemConfig"
   fi
@@ -215,7 +223,7 @@ if [ "$action" = switch ] || [ "$action" = activate ] || [ "$action" = rollback
   "$systemConfig/activate-user"
 
   if [ "$USER" != root ]; then
-    sudo -H --preserve-env=PATH "$systemConfig/activate"
+    sudo "$systemConfig/activate"
   else
     "$systemConfig/activate"
   fi