Ensure entries are sorted to avoid non-determinism in compilation, closes #4814

Author: José Valim

lib/elixir/src/elixir_def.erl

@@ -218,7 +218,7 @@ is_macro(_)         -> false.
 unwrap_definitions(File, Module) ->
   Table = elixir_module:defs_table(Module),
   Entries = ets:match(Table, {{def, '$1'}, '_', '_', '_', '_', '_', '_'}),
-  {All, Private} = unwrap_definition(Entries, File, Module, Table, [], []),
+  {All, Private} = unwrap_definition(lists:sort(Entries), File, Module, Table, [], []),
   Unreachable = elixir_locals:warn_unused_local(File, Module, Private),
   split_definition(All, Unreachable, [], [], [], [], [], {[], []}).
 

lib/elixir/test/elixir/module_test.exs

@@ -245,6 +245,17 @@ defmodule ModuleTest do
     assert ModuleHygiene.test == [1, 2, 3]
   end
 
+  test "ensure function clauses are ordered" do
+    {_, _, binary, _} =
+      defmodule Ordered do
+        def foo(:foo), do: :bar
+        def baz(:baz), do: :bat
+      end
+    atoms = :beam_lib.chunks(binary, [:atoms])
+    assert :erlang.phash2(atoms) == 53987778
+  end
+
+  # TODO: Remove this check once we depend only on 19
   if :erlang.system_info(:otp_release) >= '19' do
     test "create with generated true does not emit warnings" do
       contents =