Since the metadata has been separated to another repo, it is better to advise the user to follow the repo in their flake so they can get the latest metadata.

Hello,

First off, thank you for this flake.

I'm new to flakes, so this might be a beginner's mistake on my side.

I am running on the following error when I try to use this flake in NixOS 21.11:

error: value is a function while a list was expected

       at /nix/store/cijly7m9alsipw3x5097hnz2ayw4lw3x-source/builder.nix:127:19:

          126|       final = evalModules {
          127|         modules = modules
             |                   ^
          128|           ++ [ ({ _module.args.pkgs = pkgs; }) (import ./module) ];
(use '--show-trace' to show detailed location information)

I invoke the flake with the following command:

NIXPKGS_ALLOW_UNFREE=1 nixFlakes run   --impure ".#v1_18_1.vanilla.client"

(The nixFlakes command comes from https://nixos.wiki/wiki/Flakes#Installation_as_an_extra_command)

I tried to modify line 127 of builder.nix so that modules becomes a list with the following "patch":

diff --git a/builder.nix b/builder.nix
index 930c86a..9ccb86e 100644
--- a/builder.nix
+++ b/builder.nix
@@ -124,7 +124,7 @@ let
   mkLauncher = modules:
     let
       final = evalModules {
-        modules = modules
+        modules = [ modules ]
           ++ [ ({ _module.args.pkgs = pkgs; }) (import ./module) ];
       };
     in final.config.launcher // {

I now run into the following error:

error: value is a list while a set was expected

       at /nix/store/0gcda509wdm9zchk4m0dn433aixi5300-source/lib/modules.nix:366:44:

          365|         options = {};
          366|         config = addFreeformType (addMeta (removeAttrs m ["_file" "key" "disabledModules" "require" "imports" "freeformType"]));
             |                         

I tried an earlier version of the repository (commit 3674454b847a2bcef7d20274003b5b1c7dfa0219) and managed to run the flake correctly (it runs the script that asks for a MSA logon).

Do you have any ideas of what I'm doing wrong?

Best regards, Tony

Result

With this patch, release versions can be built without IFD.

$ nix build github:linyinfeng/minecraft.nix#v1_18_2.vanilla.client --no-allow-import-from-derivation --json
[{"drvPath":"/nix/store/f3q797lwks3ijmlx4h0r620ak13ln14f-minecraft.drv","outputs":{"out":"/nix/store/azf9nvpfqcyzxxw4mspi7510zjs3vidr-minecraft"}}]

IFD is still required to build non-release versions.

$ nix build github:linyinfeng/minecraft.nix#v1_19-pre1.vanilla.client --no-allow-import-from-derivation --json
error: cannot build '/nix/store/4xphbc1g7lnz19khkwwjgg44qzgamfi8-1.19-pre1.json.drv' during evaluation because the option 'allow-import-from-derivation' is disabled
(use '--show-trace' to show detailed location information)
$ nix build github:linyinfeng/minecraft.nix#v1_19-pre1.vanilla.client --allow-import-from-derivation --json
nix build github:linyinfeng/minecraft.nix#v1_19-pre1.vanilla.client --allow-import-from-derivation --json
[{"drvPath":"/nix/store/w60kdnxhrrhk83z02pqqwwqjb5zgz9nq-minecraft.drv","outputs":{"out":"/nix/store/lsl41qy164akl4dr0cbwb9w9svhy5zaj-minecraft"}}]

Space consumption

Prefetch these JSON files only for release versions should be acceptable, these files take up 4.8M.

$ du -h
du -h vanilla
3.1M	vanilla/asset_indices
1.6M	vanilla/versions
4.8M	vanilla

I also tried to fetch all versions including old_alpha, old_beta, and snapshot.

du -h vanilla
3.6M	vanilla/asset_indices
14M	vanilla/versions
18M	vanilla

If 18M is acceptable, we may prefetch all versions, removing IFD completely.

• Pass the missing username argument to mc
• Fix skin downloading by making the assets directory mutable
• Also do nix flake update, bump the input nixpkgs to the latest nixos-unstable