Infinite recursion after updating to 17.03

[wizeman]

Issue description

When trying to update to NixOS 17.03, I am getting an infinite recursion while evaluating the configuration of my Raspberry Pi machine:

error: while evaluating the attribute ‘keys’ at /backup/nix/nixpkgs/lib/attrsets.nix:199:44:
while evaluating anonymous function at /backup/nix/nixpkgs/lib/options.nix:117:41, called from /backup/nix/nixpkgs/lib/attrsets.nix:199:52:
while evaluating ‘scrubOptionValue’ at /backup/nix/nixpkgs/lib/options.nix:113:22, called from /backup/nix/nixpkgs/lib/options.nix:117:44:
while evaluating ‘isDerivation’ at /backup/nix/nixpkgs/lib/attrsets.nix:295:18, called from /backup/nix/nixpkgs/lib/options.nix:114:8:
while evaluating the attribute ‘keys’ at /nixdev/nixpkgs/lib/attrsets.nix:199:44:
while evaluating anonymous function at /nixdev/nixpkgs/lib/modules.nix:75:45, called from /nixdev/nixpkgs/lib/attrsets.nix:199:52:
while evaluating the attribute ‘value’ at /nixdev/nixpkgs/lib/modules.nix:300:9:
while evaluating the option `deployment.keys':
while evaluating the attribute ‘isDefined’ at /nixdev/nixpkgs/lib/modules.nix:332:5:
while evaluating ‘filterOverrides’ at /nixdev/nixpkgs/lib/modules.nix:407:21, called from /nixdev/nixpkgs/lib/modules.nix:316:18:
while evaluating ‘concatMap’ at /nixdev/nixpkgs/lib/lists.nix:79:18, called from /nixdev/nixpkgs/lib/modules.nix:413:8:
while evaluating ‘concatMap’ at /nixdev/nixpkgs/lib/lists.nix:79:18, called from /nixdev/nixpkgs/lib/modules.nix:311:17:
while evaluating anonymous function at /nixdev/nixpkgs/lib/modules.nix:311:28, called from undefined position:
while evaluating ‘dischargeProperties’ at /nixdev/nixpkgs/lib/modules.nix:374:25, called from /nixdev/nixpkgs/lib/modules.nix:312:62:
while evaluating the attribute ‘value’ at /nixdev/nixpkgs/lib/modules.nix:204:48:
while evaluating the attribute ‘config.keys’ at /nix/store/bkkxf39jic9z29s9irh7z1inx56vmgxz-nixops-1.5/share/nix/nixops/auto-luks.nix:134:5:
while evaluating the module argument `utils' in "/nix/store/bkkxf39jic9z29s9irh7z1inx56vmgxz-nixops-1.5/share/nix/nixops/auto-luks.nix":
while evaluating the attribute ‘_module.args.utils’ at /nixdev/nixpkgs/lib/attrsets.nix:199:44:
while evaluating anonymous function at /nixdev/nixpkgs/lib/modules.nix:75:45, called from /nixdev/nixpkgs/lib/attrsets.nix:199:52:
while evaluating the attribute ‘value’ at /nixdev/nixpkgs/lib/modules.nix:300:9:
while evaluating the option `_module.args':
while evaluating the attribute ‘mergedValue’ at /nixdev/nixpkgs/lib/modules.nix:327:5:
while evaluating anonymous function at /nixdev/nixpkgs/lib/modules.nix:327:32, called from /nixdev/nixpkgs/lib/modules.nix:327:19:
while evaluating ‘merge’ at /nixdev/nixpkgs/lib/types.nix:201:20, called from /nixdev/nixpkgs/lib/modules.nix:330:8:
while evaluating ‘mapAttrs’ at /nixdev/nixpkgs/lib/attrsets.nix:198:17, called from /nixdev/nixpkgs/lib/types.nix:202:9:
while evaluating ‘filterAttrs’ at /nixdev/nixpkgs/lib/attrsets.nix:115:23, called from /nixdev/nixpkgs/lib/types.nix:202:35:
while evaluating ‘concatMap’ at /nixdev/nixpkgs/lib/lists.nix:79:18, called from /nixdev/nixpkgs/lib/attrsets.nix:116:18:
while evaluating anonymous function at /nixdev/nixpkgs/lib/attrsets.nix:116:29, called from undefined position:
while evaluating anonymous function at /nixdev/nixpkgs/lib/types.nix:202:51, called from /nixdev/nixpkgs/lib/attrsets.nix:116:62:
while evaluating the attribute ‘pkgs’ at /nixdev/nixpkgs/lib/attrsets.nix:334:7:
while evaluating anonymous function at /nixdev/nixpkgs/lib/types.nix:202:86, called from /nixdev/nixpkgs/lib/attrsets.nix:334:15:
while evaluating the attribute ‘optionalValue’ at /nixdev/nixpkgs/lib/modules.nix:334:5:
while evaluating ‘filterOverrides’ at /nixdev/nixpkgs/lib/modules.nix:407:21, called from /nixdev/nixpkgs/lib/modules.nix:316:18:
while evaluating ‘concatMap’ at /nixdev/nixpkgs/lib/lists.nix:79:18, called from /nixdev/nixpkgs/lib/modules.nix:413:8:
while evaluating ‘concatMap’ at /nixdev/nixpkgs/lib/lists.nix:79:18, called from /nixdev/nixpkgs/lib/modules.nix:311:17:
while evaluating anonymous function at /nixdev/nixpkgs/lib/modules.nix:311:28, called from undefined position:
while evaluating ‘dischargeProperties’ at /nixdev/nixpkgs/lib/modules.nix:374:25, called from /nixdev/nixpkgs/lib/modules.nix:312:62:
while evaluating the attribute ‘value’ at /nixdev/nixpkgs/lib/types.nix:207:55:
while evaluating the attribute ‘pkgs’ at /nixdev/nixpkgs/nixos/modules/misc/nixpkgs.nix:100:5:
while evaluating anonymous function at /backup/nix/nixpkgs/pkgs/top-level/impure.nix:15:1, called from /nixdev/nixpkgs/nixos/modules/misc/nixpkgs.nix:100:25:
while evaluating anonymous function at /backup/nix/nixpkgs/pkgs/top-level/default.nix:20:1, called from /backup/nix/nixpkgs/pkgs/top-level/impure.nix:63:1:
while evaluating anonymous function at /backup/nix/nixpkgs/pkgs/stdenv/booter.nix:42:1, called from /backup/nix/nixpkgs/pkgs/top-level/default.nix:93:10:
while evaluating ‘fold’ at /backup/nix/nixpkgs/lib/lists.nix:29:19, called from /backup/nix/nixpkgs/pkgs/stdenv/booter.nix:73:4:
while evaluating ‘fold'’ at /backup/nix/nixpkgs/lib/lists.nix:32:15, called from /backup/nix/nixpkgs/lib/lists.nix:36:8:
while evaluating ‘folder’ at /backup/nix/nixpkgs/pkgs/stdenv/booter.nix:58:22, called from /backup/nix/nixpkgs/lib/lists.nix:35:14:
while evaluating ‘allPackages’ at /backup/nix/nixpkgs/pkgs/top-level/default.nix:83:17, called from /backup/nix/nixpkgs/pkgs/stdenv/booter.nix:69:10:
while evaluating anonymous function at /backup/nix/nixpkgs/pkgs/top-level/stage.nix:12:1, called from /backup/nix/nixpkgs/pkgs/top-level/default.nix:83:26:
while evaluating ‘fix’ at /backup/nix/nixpkgs/lib/trivial.nix:29:9, called from /backup/nix/nixpkgs/pkgs/top-level/stage.nix:150:3:
while evaluating ‘extends’ at /backup/nix/nixpkgs/lib/trivial.nix:54:24, called from /backup/nix/nixpkgs/lib/trivial.nix:29:20:
while evaluating ‘extends’ at /backup/nix/nixpkgs/lib/trivial.nix:54:24, called from /backup/nix/nixpkgs/lib/trivial.nix:54:42:
while evaluating ‘stdenvOverrides’ at /backup/nix/nixpkgs/pkgs/top-level/stage.nix:121:27, called from /backup/nix/nixpkgs/lib/trivial.nix:54:67:
while evaluating the attribute ‘stdenv.overrides’ at /backup/nix/nixpkgs/pkgs/top-level/stage.nix:100:5:
while evaluating ‘optionalAttrs’ at /backup/nix/nixpkgs/lib/attrsets.nix:321:25, called from /backup/nix/nixpkgs/pkgs/top-level/stage.nix:102:10:
while evaluating the module argument `pkgs' in "/backup/root/src/wizynet/config-tvrasp.nix":
while evaluating the attribute ‘_module.args.pkgs’ at /nixdev/nixpkgs/lib/attrsets.nix:199:44:
infinite recursion encountered, at undefined position
error: evaluation of the deployment specification failed

Steps to reproduce

The problem appears to be related to the following highlighted portion of my configuration.nix, since the infinite recursion disappears if I remove this option:

   nixpkgs = {
+    config = {
+      platform = pkgs.platforms.raspberrypi2;
+    };
     system = "armv7l-linux";
  };

It appears that at least one other user may have ran into this issue as well, according to #22014 (comment)

@Ericson2314: do you think this problem may have been introduced with #22107?

Technical details

• System: NixOS 17.03
• Nixpkgs version: 5e4b43d

[Ericson2314]

@wizeman Yes that is probably my fault. As far as I can see there is no good way to make this work as is, sorry :/. While pkgs.platform doesn't depend on anything else in pkgs, pkgs depends on platform, and Nix can't see through all the bootstrapping we do and fixed points we make to realize there actually is no cycle.

The proper solution then is to move top-level/platforms.nix into the lib. In fact, a month-old branch of mine, https://github.com/Ericson2314/nixpkgs/tree/platform-normalization does exactly that, but then also some other cleanup which is WIP. Perhaps I should make the move first, and do the refactor on top.

[wizeman]

This should really be fixed, because I think most NixOS configurations on ARM machines contain the line above, so when people upgrade to NixOS 17.03 they will run into this problem (and may not be able to figure out what's going on).

In the meantime, in case other people run into this issue, a workaround is to change the following line:

platform = pkgs.platforms.raspberrypi2;

... into:

platform = (import <nixpkgs/pkgs/top-level/platforms.nix>).raspberrypi2;

[eqyiel]

I'm seeing this issue after #24610, but now you have to import from nixpkgs/lib/systems/platforms.nix instead.

For future humans, the workaround now looks like this:

nixpkgs.config.platform = (import <nixpkgs/pkgs/top-level/platforms.nix>).raspberrypi2;

[Ericson2314]

@eqyiel I think you copied the old one by mistakte? Now the workaround would be

{
  nixpkgs.config.platform = (import <nixpkgs/lib/systems/platforms.nix>).raspberrypi2;
} # N.B. wrote `examples.nix` before, which is different

But that shouldn't be necessary:

{ lib, ... }:

{
  nixpkgs.config.platform = lib.systems.examples.raspberrypi2;
}

should work.

[eqyiel]

@Ericson2314 you're right, I mean to say that the workaround is like this:

nixpkgs.config.platform = (import <nixpkgs/lib/systems/platforms.nix>).raspberrypi2;

I'm not really sure what I'm doing though, I just started with the configuration example here. I'll try your suggestion as soon as I can and see what happens.

Edit: linked to the wrong wiki, configuration example is here

[Ericson2314]

Ah yes, it's still platforms.nix. examples.nix is something else.

[eqyiel]

Yep, you can now just use

nixpkgs.config.platform = lib.systems.platforms.raspberrypi2;

I'll see if I can update the wiki.