lib/customization: propagate function arguments in callPackagesWith

makeOverridable is very careful to ensure the arguments to the
overridden function are the same as the input function. As a result,
the arguments of hello.override are exactly the same as the original
arguments of the hello function that produced the derivation.

However, callPackagesWith calls makeOverridable with a lambda that
does not propagate the arguments. The override function for a package
instantiated with callPackagesWith will not have the original
arguments.

For example:

    nix-repl> lib.functionArgs hello.override
    { callPackage = false; fetchurl = false; hello = false; lib = false; nixos = false; stdenv = false; testers = false; }

    nix-repl> lib.functionArgs openssl.override
    { }

By copying the arguments onto the inner lambda before passing it to
makeOverridable, we can make callPackage and callPackages behave the
same.

    nix-repl> lib.functionArgs openssl.override
    { buildPackages = false; coreutils = false; cryptodev = false; enableSSL2 = true; enableSSL3 = true; fetchurl = false; lib = false; perl = false; removeReferencesTo = false; static = true; stdenv = false; withCryptodev = true; withPerl = true; }

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix
index 193e68a96933..041122feadae 100644
--- a/lib/tests/misc.nix
+++ b/lib/tests/misc.nix
@@ -55,6 +55,24 @@ runTests {
     expected = { a = false; b = false; c = true; };
   };
 
+  testCallPackageWithOverridePreservesArguments =
+    let
+      f = { a ? 0, b }: {};
+      f' = callPackageWith { a = 1; b = 2; } f {};
+    in {
+      expr = functionArgs f'.override;
+      expected = functionArgs f;
+    };
+
+  testCallPackagesWithOverridePreservesArguments =
+    let
+      f = { a ? 0, b }: { nested = {}; };
+      f' = callPackagesWith { a = 1; b = 2; } f {};
+    in {
+      expr = functionArgs f'.nested.override;
+      expected = functionArgs f;
+    };
+
 # TRIVIAL
 
   testId = {