bind: Maintain backwards compatibility for map[string]interface{} bin…

…ding (#2656)

* bind: Maintain backwards compatibility for map[string]interface{} binding

* bind to single string for map[string]interface{}{}

bind.go

@@ -159,6 +159,10 @@ func (b *DefaultBinder) bindData(destination interface{}, data map[string][]stri
  for k, v := range data {
  if isElemString {
  val.SetMapIndex(reflect.ValueOf(k), reflect.ValueOf(v[0]))
+ } else if isElemInterface {
+ // To maintain backward compatibility, we always bind to the first string value
+ // and not the slice of strings when dealing with map[string]interface{}{}
+ val.SetMapIndex(reflect.ValueOf(k), reflect.ValueOf(v[0]))
  } else {
  val.SetMapIndex(reflect.ValueOf(k), reflect.ValueOf(v))
  }

bind_test.go

@@ -497,8 +497,8 @@ func TestDefaultBinder_bindDataToMap(t *testing.T) {
  assert.NoError(t, new(DefaultBinder).bindData(&dest, exampleData, "param"))
  assert.Equal(t,
  map[string]interface{}{
- "multiple": []string{"1", "2"},
- "single": []string{"3"},
+ "multiple": "1",
+ "single": "3",
  },
  dest,
  )
@@ -509,8 +509,8 @@ func TestDefaultBinder_bindDataToMap(t *testing.T) {
  assert.NoError(t, new(DefaultBinder).bindData(&dest, exampleData, "param"))
  assert.Equal(t,
  map[string]interface{}{
- "multiple": []string{"1", "2"},
- "single": []string{"3"},
+ "multiple": "1",
+ "single": "3",
  },
  dest,
  )