Test __structuredAttrs support in autoPatchelf

This commit adds a test for the newly added support for
__structuredAttrs in autoPatchelf(hook). It copied a reasonably
small-closure binary derivation that makes use of autoPatchelf, stripped
it down for the purpose of the test, and check that autoPatchelf
correctly set the interpreter and runpath whether __structuredAttrs is
set to true or not.

pkgs/test/auto-patchelf-hook/default.nix

···
+{ lib, callPackage }:
+
+lib.recurseIntoAttrs {
+  withStructuredAttrs = callPackage ./package.nix { __structuredAttrs = true; };
+  withoutStructuredAttrs = callPackage ./package.nix { __structuredAttrs = false; };
+}

pkgs/test/auto-patchelf-hook/package.nix

···
+# This is a test for autoPatchelfHook. To test it, we just need a simple binary
+# which uses the hook. We took the derivation from tonelib-jam, which sounds
+# like a good candidate with a small closure, and trimmed it down.
+
+{ stdenv
+, lib
+, fetchurl
+, autoPatchelfHook
+, dpkg
+, freetype
+, curl
+# This test checks that the behavior of autoPatchelfHook is correct whether
+# __structuredAttrs
+# (https://nixos.org/manual/nix/stable/language/advanced-attributes#adv-attr-structuredAttrs)
+# is set or not. Hence __structuredAttrs is provided as a parameter.
+, __structuredAttrs
+}:
+
+let runtimeDependencies = [
+  (lib.getLib curl)
+  "/some/dep"
+  "/some/other/dep"
+]
+# A dependency with space only works with __structuredAttrs set to true.
+++ lib.lists.optional __structuredAttrs "/some/dep with space";
+in
+
+stdenv.mkDerivation {
+  name = "auto-patchelf-test";
+
+  src = fetchurl {
+    url = "https://tonelib.net/download/221222/ToneLib-Jam-amd64.deb";
+    sha256 = "sha256-c6At2lRPngQPpE7O+VY/Hsfw+QfIb3COIuHfbqqIEuM=";
+  };
+
+  unpackCmd = ''
+    dpkg -x $curSrc source
+  '';
+
+  nativeBuildInputs = [
+    dpkg
+    autoPatchelfHook
+  ];
+
+  installPhase = ''
+    mv usr $out
+  '';
+
+  buildInputs = [
+    freetype
+  ];
+
+  autoPatchelfIgnoreMissingDeps = [
+    "libGL.so.1"
+    "libasound.so.2"
+  ];
+
+  inherit runtimeDependencies;
+
+  # Additional phase performing the actual test.
+  installCheckPhase =
+    let allDeps = runtimeDependencies ++ [ (lib.getLib freetype) ];
+    in
+    ''
+      local binary="$out/bin/ToneLib-Jam"
+      local interpreter=$(patchelf --print-interpreter $binary)
+      local runpath=$(patchelf --print-rpath $binary)
+      local glibcStorePath="${stdenv.cc.libc}"
+
+      # Check that the glibc path is a prefix of the interpreter. If
+      # autoPatchelfHook ran correctly, the binary should have set the interpreter
+      # to point to the store.
+      echo "[auto-patchelf-hook-test]: Check that the interpreter is in the store"
+      test "''${interpreter#$glibcStorePath}" != "$interpreter"
+
+      readarray -td':' runpathArray < <(echo -n "$runpath")
+
+      echo "[auto-patchelf-hook-test]: Check that the runpath has the right number of entries"
+      test "''${#runpathArray[@]}" -eq ${builtins.toString (builtins.length allDeps)}
+
+      echo "[auto-patchelf-hook-test]: Check that the runpath contains the expected runtime deps"
+    ''
+    + lib.strings.concatStringsSep "\n"
+      (lib.lists.imap0
+        (i: path:
+          let iAsStr = builtins.toString i; in
+          ''
+            echo "[auto-patchelf-hook-test]: Check that entry ${iAsStr} is ${path}"
+            test "''${paths[${iAsStr}]}" = "$path"
+          '')
+        allDeps
+      );
+
+  doInstallCheck = true;
+  inherit __structuredAttrs;
+}

pkgs/test/default.nix

···
   pkgs-lib = recurseIntoAttrs (import ../pkgs-lib/tests { inherit pkgs; });
 
   nixpkgs-check-by-name = callPackage ./nixpkgs-check-by-name { };
+
+  auto-patchelf-hook = callPackage ./auto-patchelf-hook { };
 }