makeOverridablePythonPackage: take care of overrideAttrs

Make it possible to mix overridePythonAttrs and overrideAttrs, i.e. ((<pkg>.overrideAttrs (_: { foo = "a"; })).overridePythonAttrs (_: { })).foo now works
NixOS · Dec 19, 2024 · 13aafb0 · 13aafb0
1 parent 5265cc5
commit 13aafb0
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Showing 2 changed files with 40 additions and 15 deletions.
diff --git a/pkgs/development/interpreters/python/python-packages-base.nix b/pkgs/development/interpreters/python/python-packages-base.nix
@@ -14,8 +14,10 @@ let
 
   # Derivations built with `buildPythonPackage` can already be overridden with `override`, `overrideAttrs`, and `overrideDerivation`.
   # This function introduces `overridePythonAttrs` and it overrides the call to `buildPythonPackage`.
-  makeOverridablePythonPackage =
-    f:
+  #
+  # Overridings specified through `overridePythonAttrs` will always be applied
+  # before those specified by `overrideAttrs`, even if invoked after them.
+  makeOverridablePythonPackage = f:
     let
       mirrorArgs = lib.mirrorFunctionArgs f;
     in
@@ -31,19 +33,19 @@ let
         );
         result = f args;
 
-        overrideWith = newArgs: args // lib.toFunction newArgs args;
-        overridePythonAttrs = mirrorArgs (newArgs: makeOverridablePythonPackage f (overrideWith newArgs));
-      in
-      if builtins.isAttrs result then
-        result
-      else if builtins.isFunction result then
-        {
-          inherit overridePythonAttrs;
-          __functor = self: result;
-        }
-      else
-        result
-    );
+      overrideWith = newArgs: args // lib.toFunction newArgs args;
+      overridePythonAttrs = mirrorArgs (newArgs: makeOverridablePythonPackage f (overrideWith newArgs));
+
+      # Change the result of the function call by applying g to it
+      overrideResult = g: makeOverridablePythonPackage (mirrorArgs (args: g (f args))) origArgs;
+    in
+    if builtins.isAttrs result then result
+      // lib.optionalAttrs (result ? overrideAttrs) { overrideAttrs = fdrv: overrideResult (drv: drv.overrideAttrs fdrv); }
+    else if builtins.isFunction result then {
+      inherit overridePythonAttrs;
+      __functor = self: result;
+    }
+    else result);
 
   mkPythonDerivation =
     if python.isPy3k then ./mk-python-derivation.nix else ./python2/mk-python-derivation.nix;

diff --git a/pkgs/test/overriding.nix b/pkgs/test/overriding.nix
@@ -205,6 +205,15 @@ let
           dontWrapPythonPrograms = false;
         });
       checkOverridePythonAttrs = p: !lib.hasInfix "wrapPythonPrograms" p.postFixup;
+      overrideAttrsFooBar =
+        drv:
+        drv.overrideAttrs (
+          finalAttrs: previousAttrs: {
+            FOO = "a";
+            BAR = finalAttrs.FOO;
+          }
+        );
+      checkAttrsFooBar = drv: drv.FOO == "a" && drv.BAR == "a";
     in
     {
       overridePythonAttrs = {
@@ -215,6 +224,20 @@ let
         expr = revertOverridePythonAttrs (applyOverridePythonAttrs pip) == pip;
         expected = true;
       };
+      overrideAttrs-overridePythonAttrs-test-overrideAttrs = {
+        expr = checkAttrsFooBar (applyOverridePythonAttrs (overrideAttrsFooBar pip));
+        expected = true;
+      };
+      overrideAttrs-overridePythonAttrs-test-overridePythonAttrs = {
+        expr = checkOverridePythonAttrs (applyOverridePythonAttrs (overrideAttrsFooBar pip));
+        expected = true;
+      };
+      overrideAttrs-overridePythonAttrs-test-commutation = {
+        expr =
+          (applyOverridePythonAttrs (overrideAttrsFooBar pip))
+          == (overrideAttrsFooBar (applyOverridePythonAttrs pip));
+        expected = true;
+      };
     };
 in