lib.misc.mergeAttrsNoOverride

The following is the current implementation of this function.

mergeAttrsNoOverride = { mergeLists ? ["buildInputs" "propagatedBuildInputs"],
                           overrideSnd ? [ "buildPhase" ]
                         }: attrs1: attrs2:
    foldr (n: set:
        setAttr set n ( if set ? ${n}
            then # merge
              if elem n mergeLists # attribute contains list, merge them by concatenating
                then attrs2.${n} ++ attrs1.${n}
              else if elem n overrideSnd
                then attrs1.${n}
              else throw "error mergeAttrsNoOverride, attribute ${n} given in both attributes - no merge func defined"
            else attrs2.${n} # add attribute not existing in attr1
           )) attrs1 (attrNames attrs2);