buildPython*: unconditionally add .override

sternenseemann · sternenseemann · commit 0443b98ab3aa · 2025-10-25T00:15:34.000+02:00
To be able to splice, we can't fail to eval before returning an
attribute set. By checking for f ? override, we need to force f which
isn't always possible, whereas mirrorFunctionArgs serves as an
indirection which wraps the inner thunks in an attribute set that can
always be returned. Fortunately, there should be no case when f
evaluates successfully and does not have the override attribute, so we
can just remove the condition.

This fixes evaluation of buildPython* based packages in certain splicing
situations by being lazier. An example of this is
pkgsCross.ghcjs.buildPackages.nixpkgs-openjdk-updater on staging right
now (ff5098e).
diff --git a/pkgs/development/interpreters/python/python-packages-base.nix b/pkgs/development/interpreters/python/python-packages-base.nix
@@ -39,7 +39,7 @@ let
       else
         result
     )
-    // lib.optionalAttrs (f ? override) {
+    // {
       # Support overriding `f` itself, e.g. `buildPythonPackage.override { }`.
       # Ensure `makeOverridablePythonPackage` is applied to the result.
       override = lib.mirrorFunctionArgs f.override (fdrv: makeOverridablePythonPackage (f.override fdrv));

Original file line number	Diff line number	Diff line change
`@@ -39,7 +39,7 @@ let`
`39`	`39`	`else`
`40`	`40`	`result`
`41`	`41`	`)`
`42`		`- // lib.optionalAttrs (f ? override) {`
	`42`	`+ // {`
`43`	`43`	# Support overriding `f` itself, e.g. `buildPythonPackage.override { }`.
`44`	`44`	# Ensure `makeOverridablePythonPackage` is applied to the result.
`45`	`45`	`override = lib.mirrorFunctionArgs f.override (fdrv: makeOverridablePythonPackage (f.override fdrv));`