From d2e4af7c7eaed58f62e61bc53818e47ba2555f24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20=C4=8Cun=C3=A1t?= <vcunat@gmail.com>
Date: Sun, 29 Jan 2017 11:50:21 +0100
Subject: [PATCH] stdenv: allow querying meta on disallowed packages

In the end I've chosen to do the check when evaluating the name.
There were two tricky points to consider:
 - nix-env -qa (changes in there tend to be very slow to get released)
 - hydra.nixos.org
   https://github.com/NixOS/nixpkgs/pull/9305#issuecomment-132791730
---
 lib/check-meta.nix              | 21 ++++++++++++++++-----
 pkgs/stdenv/generic/default.nix |  2 +-
 pkgs/top-level/release-lib.nix  |  3 +++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/lib/check-meta.nix b/lib/check-meta.nix
index b490d63922be65..5499177ff62b5b 100644
--- a/lib/check-meta.nix
+++ b/lib/check-meta.nix
@@ -2,17 +2,28 @@ let
   lib = import ./default.nix;
 in rec {
 
-  # Extend a derivation with a check for brokenness, license, etc.
-  # Throw a descriptive error when the check fails.
-  # Note: no dependencies are checked in this step.
-  addMetaCheck = config: meta: drv:
+  # Extend attributes to be passed to derivation (or similar) with a check
+  # for brokenness, license, etc.  Throw a descriptive error if the check fails.
+  # Note: no dependencies are checked in this step, but this should be done before
+  #   applying the `derivation` primitive in order to "propagate to dependants".
+  addMetaCheckInner = config: meta: drv:
     let
       name = drv.name or "«name-missing»";
       position = meta.position or "«unknown-file»";
       v = checkMetaValidity { inherit meta config; inherit (drv) system; };
     in
-      if v.valid then drv
+      # As a compromise, do the check when evaluating the name attribute;
+      #   the intention is to also catch any attempt to show in nix-env -qa,
+      #   while allowing to query meta (surprisingly even --no-name doesn't break that).
+      drv // {
+        name = if v.valid then drv.name
           else throwEvalHelp (removeAttrs v ["valid"] // { inherit name position; });
+      };
+
+  # Make sure the dependencies are evaluted when accessing the name.
+  # The input is a derivation, i.e. *after* applying the `derivation` primitive.
+  addMetaCheckOuter = drv:
+    drv // { name = assert drv.outPath != null; drv.name; };
 
   # Throw a descriptive error message for a failed evaluation check.
   throwEvalHelp = { reason, errormsg, name, position }:
diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix
index 39bfe4516a8a83..801f732919de73 100644
--- a/pkgs/stdenv/generic/default.nix
+++ b/pkgs/stdenv/generic/default.nix
@@ -169,7 +169,7 @@ let
     in
 
       lib.addPassthru
-        (derivation (lib.addMetaCheck config meta derivationArg))
+        (lib.addMetaCheckOuter (derivation (lib.addMetaCheckInner config meta derivationArg)))
         ( {
             overrideAttrs = f: mkDerivation (attrs // (f attrs));
             inherit meta passthru;
diff --git a/pkgs/top-level/release-lib.nix b/pkgs/top-level/release-lib.nix
index 5fe87711c01650..a8aa26e64339fe 100644
--- a/pkgs/top-level/release-lib.nix
+++ b/pkgs/top-level/release-lib.nix
@@ -85,6 +85,9 @@ rec {
   packagePlatforms = mapAttrs (name: value:
     let res = builtins.tryEval (
       if isDerivation value then
+        # Hopefully a reliable way to test whether the derivation evaluates,
+        # including brokenness/license checks in any dependencies.
+        assert value.outPath != null;
         value.meta.hydraPlatforms or (value.meta.platforms or [ "x86_64-linux" ])
       else if value.recurseForDerivations or false || value.recurseForRelease or false then
         packagePlatforms value