From 4a26f177c93099e551ed5cd949a89f631da53a52 Mon Sep 17 00:00:00 2001
From: "Markus S. Wamser" <github-dev@mail2013.wamser.eu>
Date: Tue, 27 Oct 2020 10:01:32 +0100
Subject: [PATCH] stdenv/check-meta: add hint to NIXPKGS_ALLOW_* for
 unfree/broken/unsupported system

---
 pkgs/stdenv/generic/check-meta.nix | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/pkgs/stdenv/generic/check-meta.nix b/pkgs/stdenv/generic/check-meta.nix
index c06f17b6fc19..b93ea558eac2 100644
--- a/pkgs/stdenv/generic/check-meta.nix
+++ b/pkgs/stdenv/generic/check-meta.nix
@@ -88,13 +88,28 @@ let
     broken-outputs = remediateOutputsToInstall;
     unknown-meta = x: "";
   };
+  remediation_env_var = allow_attr: {
+    Unfree = "NIXPKGS_ALLOW_UNFREE";
+    Broken = "NIXPKGS_ALLOW_BROKEN";
+    UnsupportedSystem = "NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM";
+  }.${allow_attr};
+  remediation_phrase = allow_attr: {
+    Unfree = "unfree packages";
+    Broken = "broken packages";
+    UnsupportedSystem = "packages that are unsupported for this system";
+  }.${allow_attr};
   remediate_whitelist = allow_attr: attrs:
     ''
-      a) For `nixos-rebuild` you can set
+      a) To temporarily allow ${remediation_phrase allow_attr}, you can use an environment variable
+         for a single invocation of the nix tools.
+
+           $ export ${remediation_env_var allow_attr}=1
+
+      b) For `nixos-rebuild` you can set
         { nixpkgs.config.allow${allow_attr} = true; }
       in configuration.nix to override this.
 
-      b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
+      c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allow${allow_attr} = true; }
       to ~/.config/nixpkgs/config.nix.
     '';