factorio: use real instead of sample in download help; warn about credentials in store

pkgs/by-name/fa/factorio/package.nix

@@ -40,46 +40,46 @@ let
 
   mods = args.mods or [ ];
 
-  helpMsg = ''
-
-    ===FETCH FAILED===
-    Please ensure you have set the username and token with config.nix, or
-    /etc/nix/nixpkgs-config.nix if on NixOS.
-
-    Your token can be seen at https://factorio.com/profile (after logging in). It is
-    not as sensitive as your password, but should still be safeguarded. There is a
-    link on that page to revoke/invalidate the token, if you believe it has been
-    leaked or wish to take precautions.
-
-    Example:
-    {
-      packageOverrides = pkgs: {
-        factorio = pkgs.factorio.override {
-          username = "FactorioPlayer1654";
-          token = "d5ad5a8971267c895c0da598688761";
+  helpMsg =
+    { dlName, storeName }:
+    ''
+
+      ===FETCH FAILED===
+      Please ensure you have set the username and token with config.nix, or
+      /etc/nix/nixpkgs-config.nix if on NixOS.
+
+      Your token can be seen at https://factorio.com/profile (after logging in).
+      Beware this will add the credentials to the Nix store, which is
+      world-readable on the local machine. It is not as sensitive as your
+      password, but should still be safeguarded. There is a link on that page to
+      revoke/invalidate the token, if you believe it has been leaked or wish to
+      take precautions.
+
+      Example:
+      {
+        packageOverrides = pkgs: {
+          factorio = pkgs.factorio.override {
+            username = "FactorioPlayer1654";
+            token = "d5ad5a8971267c895c0da598688761";
+          };
         };
-      };
-    }
+      }
 
-    Alternatively, instead of providing the username+token, you may manually
-    download the release through https://factorio.com/download , then add it to
-    the store using e.g.:
+      Alternatively, instead of providing the username+token, you may manually
+      download the release through https://factorio.com/download , then add it to
+      the store using e.g.:
 
-      releaseType=alpha
-      version=0.17.74
-      nix-prefetch-url file://\''$HOME/Downloads/factorio_\''${releaseType}_x64_\''${version}.tar.xz --name factorio_\''${releaseType}_x64-\''${version}.tar.xz
+        nix-prefetch-url file://\''$HOME/Downloads/${dlName} --name ${storeName}
 
-    Note the ultimate "_" is replaced with "-" in the --name arg!
+      If you go this route you might want to tell Nix to explicitly hold on to the
+      source tarball. Otherwise it could get GC'd from the Nix store and you'd
+      have to redownload it next time the package wants to rebuild to use a newer
+      dependency. E.g. if you're using NixOS:
 
-    If you go this route you might want to tell Nix to explicitly hold on to the
-    source tarball. Otherwise it could get GC'd from the Nix store and you'd
-    have to redownload it next time the package wants to rebuild to use a newer
-    dependency. E.g. if you're using NixOS:
-
-      system.extraDependencies = [
-        factorio.src
-      ];
-  '';
+        system.extraDependencies = [
+          factorio.src
+        ];
+    '';
 
   desktopItem = makeDesktopItem {
     name = "factorio";
@@ -155,7 +155,10 @@ let
                   '';
               failureHook = ''
                 cat <<EOF
-                ${helpMsg}
+                ${helpMsg {
+                  dlName = if candidateHashFilenames != [ ] then builtins.head candidateHashFilenames else name;
+                  storeName = name;
+                }}
                 EOF
               '';
             })