Update changelog and add test for mixed float/int lists

CHANGELOG.md

@@ -14,11 +14,12 @@ versions.
 
 - The resource type name can now be overridden with
   `#[register_impl(name = "...")]` (#638)
+- Floats can be decoded from integers (#641, fixes #603)
 
 ### Fixed
 
 - The optional `register` attribute on `#[register_impl]` works as advertised
-now (#638)
+  now (#638)
 
 ### Changed
 

rustler_tests/lib/rustler_test.ex

@@ -33,6 +33,7 @@ defmodule RustlerTest do
 
   def sum_list(_), do: err()
   def make_list(), do: err()
+  def sum_list_as_floats(_), do: err()
 
   def compare_local_pids(_, _), do: err()
   def are_equal_local_pids(_, _), do: err()

rustler_tests/native/rustler_test/src/test_list.rs

@@ -18,3 +18,8 @@ pub fn sum_list(iter: ListIterator) -> NifResult<i64> {
 pub fn make_list() -> Vec<usize> {
     vec![1, 2, 3]
 }
+
+#[rustler::nif]
+pub fn sum_list_as_floats(list: Vec<f64>) -> f64 {
+    list.into_iter().sum()
+}

rustler_tests/test/list_test.exs

@@ -22,4 +22,10 @@ defmodule RustlerTest.ListTest do
   test "simple list construction with sum" do
     assert RustlerTest.sum_list(RustlerTest.make_list()) == 6
   end
+
+  test "sum float list" do
+    assert_in_delta RustlerTest.sum_list_as_floats([1, 2, 3, 4]), 10.0, 0.01
+    assert_in_delta RustlerTest.sum_list_as_floats([1.0, 2.0, 3.0, 4.0]), 10.0, 0.01
+    assert_in_delta RustlerTest.sum_list_as_floats([1, 2.0, 3, 4.0]), 10.0, 0.01
+  end
 end