fix: backport comparable check to <1.20

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

mapstructure.go

@@ -1163,7 +1163,7 @@ func (d *Decoder) decodeArray(name string, data interface{}, val reflect.Value)
 
  valArray := val
 
- if valArray.Comparable() && valArray.Interface() == reflect.Zero(valArray.Type()).Interface() || d.config.ZeroFields {
+ if isComparable(valArray) && valArray.Interface() == reflect.Zero(valArray.Type()).Interface() || d.config.ZeroFields {
  // Check input type
  if dataValKind != reflect.Array && dataValKind != reflect.Slice {
  if d.config.WeaklyTypedInput {

reflect_go1_19.go

@@ -0,0 +1,9 @@
+//go:build !go1.20
+
+package mapstructure
+
+import "reflect"
+
+func isComparable(v reflect.Value) bool {
+ return true
+}

reflect_go1_20.go

@@ -0,0 +1,10 @@
+//go:build go1.20
+
+package mapstructure
+
+import "reflect"
+
+// TODO: remove once we drop support for Go <1.20
+func isComparable(v reflect.Value) bool {
+ return v.Comparable()
+}