fix the way how environment variables, especially PATH is handled

default.nix

@@ -28,6 +28,7 @@ let
   startServices = pkgs.writeScript "startServices" ''
     #!/bin/sh
     export STATEDIR="${"\$"}{STATEDIR-$(pwd)/var}"
+    export PATH="${pkgs.coreutils}/bin"
 
     mkdir -p $STATEDIR/{run,log}
 

supervisord.nix

@@ -16,6 +16,10 @@ let
           PATH = "/some/path";
         };
       };
+      path = mkOption {
+        default = [];
+        description = "Current directory when running the command";
+      };
       stopsignal = mkOption {
         default = "TERM";
       };
@@ -75,7 +79,13 @@ in {
           ''
           [program:${name}]
           command=${cfg.command}
-          environment=${concatMapStrings (name: "${name}=\"${toString (getAttr name cfg.environment)}\",") (attrNames cfg.environment)}
+          environment=${concatStrings
+            (mapAttrsToList (name: value: "${name}=\"${value}\",") (
+              cfg.environment // { PATH = concatStringsSep ":"
+                [("%(ENV_PATH)s") (cfg.path) (maybeAttr "PATH" "" cfg.environment)];
+              }
+            )
+          )}
           directory=${cfg.directory}
           redirect_stderr=true
           startsecs=${toString cfg.startsecs}

systemd.nix

@@ -49,11 +49,8 @@ in {
           name = name;
           value = {
             command = pkgs.writeScript "${name}-run" (configToCommand name cfg);
-            environment = (if hasAttr "environment" cfg then cfg.environment else {}) //
-              (if hasAttr "path" cfg then
-                { PATH = "%(ENV_PATH)s:" + concatStringsSep ":" (map (prg: "${prg}/bin") cfg.path); }
-               else {
-               PATH="%(ENV_PATH)s"; });
+            environment = cfg.environment;
+            path = cfg.path;
             stopsignal = if hasAttr "KillSignal" cfg.serviceConfig then
               substring 3 (stringLength cfg.serviceConfig.KillSignal) cfg.serviceConfig.KillSignal
             else "TERM";