overrideSDK: support all deps attributes

This is effectively a rewrite of `overrideSDK`. It was required because
`wrapGAppsHook` propagates `depsTargetTarget` with the expectation that
it will effectively be `buildInputs` when the hook is itself used as a
`nativeBuildInput`. This propagates Gtk, which itself propagates the
default Dariwn SDK, making it effectively impossible to override the SDK
when a package depends on Gtk and uses `wrapGAppsHook`.

This rewrite implements the following improvements:

* Cross-compilation should be supported correctly (untested);
* Supports public and private frameworks;
* Supports SDK `libs`;
* Remaps instead of replacing extra (native) build inputs in the stdenv;
* Updates any Darwin framework references in `nix-support`; and
* It updates `xcodebuild` regardless of which input its in.

The implementation avoids recursion for performance reasons. Instead, it
enumerates transitive dependencies and walks the list from the leaf
packages backwards to the parent packages.

1 files changed, 11 insertions, 119 deletions

diff --git a/pkgs/stdenv/adapters.nix b/pkgs/stdenv/adapters.nix
index c6b0aece45309..2304b3289b7eb 100644
--- a/pkgs/stdenv/adapters.nix
+++ b/pkgs/stdenv/adapters.nix
@@ -317,125 +317,17 @@ rec {
   # `sdkVersion` can be any of the following:
   # * A version string indicating the requested SDK version; or
   # * An attrset consisting of either or both of the following fields: darwinSdkVersion and darwinMinVersion.
-  overrideSDK = stdenv: sdkVersion:
-    let
-      inherit (
-        { inherit (stdenv.hostPlatform) darwinMinVersion darwinSdkVersion; }
-        // (if lib.isAttrs sdkVersion then sdkVersion else { darwinSdkVersion = sdkVersion; })
-      ) darwinMinVersion darwinSdkVersion;
-
-      sdk = pkgs.darwin."apple_sdk_${lib.replaceStrings [ "." ] [ "_" ] darwinSdkVersion}";
-      # TODO: Make this unconditional after #229210 has been merged,
-      # and the 10.12 SDK is updated to follow the new structure.
-      Libsystem = if darwinSdkVersion == "10.12" then pkgs.darwin.Libsystem else sdk.Libsystem;
-
-      replacePropagatedFrameworks = pkg:
-        let
-          propagatedInputs = pkg.propagatedBuildInputs;
-          mappedInputs = map mapPackageToSDK propagatedInputs;
-
-          env = {
-            inherit (pkg) outputs;
-            # Map old frameworks to new ones and the package’s outputs to their original outPaths.
-            # Also map any packages that have propagated frameworks to their proxy packages using
-            # the requested SDK version. These mappings are rendered into tab-separated files to be
-            # parsed and read back with `read`.
-            dependencies = lib.concatMapStrings (pair: "${pair.fst}\t${pair.snd}\n") (lib.zipLists propagatedInputs mappedInputs);
-            pkgOutputs = lib.concatMapStrings (output: "${output}\t${(lib.getOutput output pkg).outPath}\n") pkg.outputs;
-            passAsFile = [ "dependencies" "pkgOutputs" ];
-          };
-        in
-        # Only remap the package’s propagated inputs if there are any and if any of them were themselves remapped.
-        if lib.length propagatedInputs > 0 && propagatedInputs != mappedInputs
-          then pkgs.runCommand pkg.name env ''
-            # Iterate over the outputs in the package being replaced to make sure the proxy is
-            # a fully functional replacement. This is like `symlinkJoin` except for outputs and
-            # the contents of `nix-support`, which will be customized for the requested SDK.
-            while IFS=$'\t\n' read -r outputName pkgOutputPath; do
-              mkdir -p "''${!outputName}"
-
-              for targetPath in "$pkgOutputPath"/*; do
-                targetName=$(basename "$targetPath")
-
-                # `nix-support` is special-cased because any propagated inputs need their SDK
-                # frameworks replaced with those from the requested SDK.
-                if [ "$targetName" == "nix-support" ]; then
-                  mkdir "''${!outputName}/nix-support"
-
-                  for file in "$targetPath"/*; do
-                    fileName=$(basename "$file")
-
-                    if [ "$fileName" == "propagated-build-inputs" ]; then
-                      cp "$file" "''${!outputName}/nix-support/$fileName"
-
-                      while IFS=$'\t\n' read -r oldFramework newFramework; do
-                        substituteInPlace "''${!outputName}/nix-support/$fileName" \
-                          --replace "$oldFramework" "$newFramework"
-                      done < "$dependenciesPath"
-                    fi
-                  done
-                else
-                  ln -s "$targetPath" "''${!outputName}/$targetName"
-                fi
-              done
-            done < "$pkgOutputsPath"
-          ''
-        else pkg;
-
-      # Remap a framework from one SDK version to another.
-      mapPackageToSDK = pkg:
-        let
-          name = lib.getName pkg;
-          framework = lib.removePrefix "apple-framework-" name;
-        in
-        /**/ if pkg == null then pkg
-        else if name != framework then sdk.frameworks."${framework}"
-        else replacePropagatedFrameworks pkg;
-
-      mapRuntimeToSDK = pkg:
-        # Only remap xcbuild for now, which exports the SDK used to build it.
-        if pkg != null && lib.isAttrs pkg && lib.getName pkg == "xcodebuild"
-          then pkg.override { stdenv = overrideSDK stdenv { inherit darwinMinVersion darwinSdkVersion; }; }
-          else pkg;
-
-      mapInputsToSDK = inputs: args:
-        let
-          runsAtBuild = lib.flip lib.elem [
-            "depsBuildBuild"
-            "depsBuildBuildPropagated"
-            "nativeBuildInputs"
-            "propagatedNativeBuildInputs"
-            "depsBuildTarget"
-            "depsBuildTargetPropagated"
-          ];
-          atBuildInputs = lib.filter runsAtBuild inputs;
-          atRuntimeInputs = lib.subtractLists atBuildInputs inputs;
-        in
-        lib.genAttrs atRuntimeInputs (input: map mapPackageToSDK (args."${input}" or [ ]))
-        // lib.genAttrs atBuildInputs (input: map mapRuntimeToSDK (args."${input}" or [ ]));
-
-      mkCC = cc: cc.override {
-        bintools = cc.bintools.override { libc = Libsystem; };
-        libc = Libsystem;
-      };
-    in
-    # TODO: make this work across all input types and not just propagatedBuildInputs
-    stdenv.override (old: {
-      buildPlatform = old.buildPlatform // { inherit darwinMinVersion darwinSdkVersion; };
-      hostPlatform = old.hostPlatform // { inherit darwinMinVersion darwinSdkVersion; };
-      targetPlatform = old.targetPlatform // { inherit darwinMinVersion darwinSdkVersion; };
-
-      allowedRequisites = null;
-      cc = mkCC old.cc;
-
-      extraBuildInputs = [sdk.frameworks.CoreFoundation ];
-      mkDerivationFromStdenv = extendMkDerivationArgs old (mapInputsToSDK [
-        "buildInputs"
-        "nativeBuildInputs"
-        "propagatedNativeBuildInputs"
-        "propagatedBuildInputs"
-      ]);
-    });
+  overrideSDK = import ./darwin/override-sdk.nix {
+    inherit lib extendMkDerivationArgs;
+    inherit (pkgs)
+      stdenvNoCC
+      pkgsBuildBuild
+      pkgsBuildHost
+      pkgsBuildTarget
+      pkgsHostHost
+      pkgsHostTarget
+      pkgsTargetTarget;
+  };
 
   withDefaultHardeningFlags = defaultHardeningFlags: stdenv: let
     bintools = let