From d4cec7511db159523a0101f36033393533bb4309 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Tue, 12 Nov 2024 19:49:39 +0100
Subject: [PATCH] nix-everything: Remove libs, add dev and devdoc package
 outputs

The new package output attributes are somewhat experimental, and
provided for compatibility most of all.

We'll see how well this goes before the changes proposed in
https://github.com/NixOS/nix/issues/6507
---
 packaging/everything.nix | 139 +++++++++++++++++++++++++++++----------
 1 file changed, 104 insertions(+), 35 deletions(-)

diff --git a/packaging/everything.nix b/packaging/everything.nix
index 6f6bbc6aa85..458d26c306b 100644
--- a/packaging/everything.nix
+++ b/packaging/everything.nix
@@ -5,12 +5,10 @@
 
   nix-util,
   nix-util-c,
-  nix-util-test-support,
   nix-util-tests,
 
   nix-store,
   nix-store-c,
-  nix-store-test-support,
   nix-store-tests,
 
   nix-fetchers,
@@ -18,7 +16,6 @@
 
   nix-expr,
   nix-expr-c,
-  nix-expr-test-support,
   nix-expr-tests,
 
   nix-flake,
@@ -38,45 +35,84 @@
   nix-external-api-docs,
 
   nix-perl-bindings,
+
+  testers,
+  runCommand,
 }:
 
+let
+  dev = stdenv.mkDerivation (finalAttrs: {
+    name = "nix-${nix-cli.version}-dev";
+    pname = "nix";
+    version = nix-cli.version;
+    dontUnpack = true;
+    dontBuild = true;
+    libs = map lib.getDev [
+      nix-cmd
+      nix-expr
+      nix-expr-c
+      nix-fetchers
+      nix-flake
+      nix-main
+      nix-main-c
+      nix-store
+      nix-store-c
+      nix-util
+      nix-util-c
+      nix-perl-bindings
+    ];
+    installPhase = ''
+      mkdir -p $out/nix-support
+      echo $libs >> $out/nix-support/propagated-build-inputs
+    '';
+    passthru = {
+      tests = {
+        pkg-config =
+          testers.hasPkgConfigModules {
+            package = finalAttrs.finalPackage;
+          };
+      };
+
+      # If we were to fully emulate output selection here, we'd confuse the Nix CLIs,
+      # because they rely on `drvPath`.
+      dev = finalAttrs.finalPackage.out;
+
+      libs = throw "`nix.dev.libs` is not meant to be used; use `nix.libs` instead.";
+    };
+    meta = {
+      pkgConfigModules = [
+        "nix-cmd"
+        "nix-expr"
+        "nix-expr-c"
+        "nix-fetchers"
+        "nix-flake"
+        "nix-main"
+        "nix-main-c"
+        "nix-store"
+        "nix-store-c"
+        "nix-util"
+        "nix-util-c"
+      ];
+    };
+  });
+  devdoc = buildEnv {
+    name = "nix-${nix-cli.version}-devdoc";
+    paths = [
+      nix-internal-api-docs
+      nix-external-api-docs
+    ];
+  };
+
+in
 (buildEnv {
   name = "nix-${nix-cli.version}";
   paths = [
-    nix-util
-    nix-util-c
-    nix-util-test-support
-    nix-util-tests
-
-    nix-store
-    nix-store-c
-    nix-store-test-support
-    nix-store-tests
-
-    nix-fetchers
-    nix-fetchers-tests
-
-    nix-expr
-    nix-expr-c
-    nix-expr-test-support
-    nix-expr-tests
-
-    nix-flake
-    nix-flake-tests
-
-    nix-main
-    nix-main-c
-
-    nix-cmd
+    # unfortunately, `buildEnv` doesn't support multiple outputs
 
     nix-cli
 
+    # TODO: separate doc output attribute?
     nix-manual
-    nix-internal-api-docs
-    nix-external-api-docs
-
-  ] ++ lib.optionals (stdenv.buildPlatform.canExecute stdenv.hostPlatform) [
-    nix-perl-bindings
   ];
 
   meta.mainProgram = "nix";
@@ -85,12 +121,25 @@
   doInstallCheck = true;
 
   checkInputs = [
-    # Actually run the unit tests too
+    # Make sure the unit tests have passed
     nix-util-tests.tests.run
     nix-store-tests.tests.run
     nix-expr-tests.tests.run
+    nix-fetchers-tests.tests.run
     nix-flake-tests.tests.run
-  ];
+
+    # dev bundle is ok
+    # (checkInputs must be empty paths??)
+    (runCommand "check-pkg-config" { checked = dev.tests.pkg-config; } "mkdir $out")
+  ] ++
+    (if stdenv.buildPlatform.canExecute stdenv.hostPlatform
+    then [
+      # TODO: add perl.tests
+      nix-perl-bindings
+    ]
+    else [
+      nix-perl-bindings
+    ]);
   installCheckInputs = [
     nix-functional-tests
   ];
@@ -128,5 +177,25 @@
         nix-main-c
       ;
     };
+
+    tests = prevAttrs.passthru.tests or {} // {
+      # TODO: create a proper fixpoint and:
+      # pkg-config =
+      #   testers.hasPkgConfigModules {
+      #     package = finalPackage;
+      #   };
+    };
+
+    /**
+      A derivation referencing the `dev` outputs of the Nix libraries.
+     */
+    inherit dev;
+    inherit devdoc;
+    outputs = [ "out" "dev" "devdoc" ];
+    all = lib.attrValues (lib.genAttrs finalAttrs.passthru.outputs (outName: finalAttrs.finalPackage.${outName}));
+  };
+  meta = prevAttrs.meta // {
+    description = "The Nix package manager";
+    pkgConfigModules = dev.meta.pkgConfigModules;
   };
 })