I have a situation that I can not figure out yet for some time and it drives me nuts. Either Enum.sort is not working as expected either I am doing it wrong.
I have some rules have a name and depend on each other. Source is the name of the dependency. I am trying to sort them ascending by dependency to be able to use them later to compute some amounts:

rules = [
  %{
    name:  "ambassador1",
    source: "ambassadors"
  },
  %{
    name: "zuppler fee",
    source: "total"
  },
  %{
    name:  "ambassadors",
    source: "zuppler fee"
  }
]

sorter = fn
  sorter = fn
  %{name: name1}, %{source: source2} when name1 == source2 -> true
  %{source: source1}, %{name: name2} when source1 == name2 -> false
  %{name: name1, source: source1}, %{name: name2, source: source2} when name1 == name2 and source1 == source2 -> true
  %{name: name1, source: source1}, %{name: name2, source: source2} -> name1 < name2 and source1 < source2
end
  _, _ -> false
end
rules |> Enum.sort(sorter) |> IO.inspect()

Result is:

[
  %{name: "ambassadors", source: "zuppler fee"},
  %{name: "zuppler fee", source: "total"},
  %{name: "ambassador1", source: "ambassadors"}
]

when the expected result would be something like:

[
  %{name: "zuppler fee", source: "total"},
  %{name: "ambassadors", source: "zuppler fee"},
  %{name: "ambassador1", source: "ambassadors"}
]

Can somebody give me a hint?