fix(extensions): propagate extensions to Collection values

Ensure that when RegisterExtensions() is called on a non-empty
collection, new extensions are propagated to the collection's existing
values.

Signed-off-by: Sergei Trofimov <[email protected]>

extensions/collection.go

@@ -134,6 +134,15 @@ func (o *Collection[P, I]) RegisterExtensions(exts Map) error {
 
 	o.valueExtensions.Set(exts)
 
+	for i := 0; i < len(o.Values); i++ {
+		var vi I = &o.Values[i]
+		if vi.GetExtensions() == nil {
+			if err := vi.RegisterExtensions(exts); err != nil {
+				return fmt.Errorf("error at index %d: %w", i, err)
+			}
+		}
+	}
+
 	return nil
 }
 

extensions/collection_test.go

@@ -170,6 +170,18 @@ func Test_Collection_GetExtensions(t *testing.T) {
 	assert.NotNil(t, c.GetExtensions())
 }
 
+func Test_Collection_RegisterExtensions(t *testing.T) {
+	c := NewCollection[testExtensible]()
+
+	e := testExtensible{}
+	c.Add(&e)
+
+	err := c.RegisterExtensions(Map{testPoint: &testExtensions{}})
+	require.NoError(t, err)
+
+	assert.NotNil(t, c.Values[0].GetExtensions())
+}
+
 func Test_Map(t *testing.T) {
 	m := NewMap()
 	assert.Equal(t, 0, len(m))