👔 up: structs - init default value will skip for empty []struct field

structs/init.go

@@ -89,7 +89,7 @@ func initDefaults(rv reflect.Value, opt *InitOptions) error {
 			continue
 		}
 
-		// skip on field has value
+		// Skip init on field has value. but will check slice and pointer field
 		if !fv.IsZero() {
 			// special: handle for pointer struct field
 			if fv.Kind() == reflect.Pointer {
@@ -140,6 +140,11 @@ func initDefaults(rv reflect.Value, opt *InitOptions) error {
 
 			// init sub struct in slice. like `[]SubStruct` or `[]*SubStruct`
 			if el.Kind() == reflect.Struct {
+				// up: if slice elem is struct and slice len=0, will be skip init default value
+				if fv.Len() == 0 {
+					continue
+				}
+
 				// make sub-struct and init. like: `SubStruct`
 				subFv := reflect.New(el)
 				subFvE := subFv.Elem()

structs/init_test.go

@@ -192,10 +192,19 @@ func TestInitDefaults_initStructSlice(t *testing.T) {
 
 	u := &User{}
 	err := structs.Init(u)
+	// dump.P(u)
+	assert.NoErr(t, err)
+	assert.Empty(t, u.Extra)
+
+	u = &User{Extra: []ExtraDefault{{City: "sh"}, {Github: "some url"}}}
+	err = structs.Init(u)
 	dump.P(u)
 	assert.NoErr(t, err)
 	assert.NotEmpty(t, u.Extra)
-	assert.Eq(t, "chengdu", u.Extra[0].City)
+	assert.Eq(t, "sh", u.Extra[0].City)
+	assert.NotEmpty(t, u.Extra[0].Github)
+	assert.Eq(t, "chengdu", u.Extra[1].City)
+	assert.Eq(t, "some url", u.Extra[1].Github)
 
 	// test for slice struct field
 	type User1 struct {
@@ -208,15 +217,15 @@ func TestInitDefaults_initStructSlice(t *testing.T) {
 	err = structs.Init(u1)
 	dump.P(u1)
 	assert.NoErr(t, err)
-	assert.NotEmpty(t, u1.Extra)
-	assert.Eq(t, "chengdu", u1.Extra[0].City)
+	assert.Empty(t, u1.Extra)
 
 	// test for not empty slice struct field
 	u2 := &User1{Extra: []*ExtraDefault{{City: "sh"}}}
 	err = structs.Init(u2)
 	// dump.P(u2)
 	assert.NoErr(t, err)
 	assert.Eq(t, "sh", u2.Extra[0].City)
+	assert.NotEmpty(t, "sh", u2.Extra[0].Github)
 }
 
 func TestInitDefaults_ptrField(t *testing.T) {