fix: update setupValuerAndSetter to use default values when pointer t…

…ypes are nil

scan.go

@@ -66,13 +66,21 @@ func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []int
 	db.RowsAffected++
 	db.AddError(rows.Scan(values...))
 	joinedNestedSchemaMap := make(map[string]interface{})
+	fieldsWithValueMap := make(map[string]bool)
 	for idx, field := range fields {
 		if field == nil {
 			continue
 		}
 
 		if len(joinFields) == 0 || len(joinFields[idx]) == 0 {
-			db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
+			fieldIsEmbeddedPointerTypeStruct := len(field.BindNames) > 1 && len(field.StructField.Index) > 0 && field.StructField.Index[0] < 0
+			fieldValue := reflect.ValueOf(values[idx]).Elem()
+			if !fieldIsEmbeddedPointerTypeStruct && fieldValue.Kind() == reflect.Ptr && fieldValue.IsNil() {
+				db.AddError(field.Set(db.Statement.Context, reflectValue, field.DefaultValueInterface))
+			} else {
+				fieldsWithValueMap[field.BindName()] = fieldValue.Kind() == reflect.Ptr && !fieldValue.IsNil()
+				db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
+			}
 		} else { // joinFields count is larger than 2 when using join
 			var isNilPtrValue bool
 			var relValue reflect.Value
@@ -109,6 +117,37 @@ func (db *DB) scanIntoStruct(rows Rows, reflectValue reflect.Value, values []int
 		// release data to pool
 		field.NewValuePool.Put(values[idx])
 	}
+
+	if dest := reflect.Indirect(db.Statement.ReflectValue); len(db.Statement.Clauses) == 0 && dest.Kind() == reflect.Struct {
+		resetEmbeddedPointerTypeStruct(dest, db.Statement.Schema, fieldsWithValueMap)
+	}
+}
+
+func resetEmbeddedPointerTypeStruct(dest reflect.Value, schema *schema.Schema, fieldsWithValueMap map[string]bool) {
+	for i := 0; i < dest.NumField(); i++ {
+		field := schema.ParseField(dest.Type().Field(i))
+		if field.EmbeddedSchema != nil && field.FieldType.Kind() == reflect.Ptr {
+			if !wasValueScannedIntoEmbeddedStruct(field, fieldsWithValueMap) && dest.Field(i).Kind() == reflect.Ptr && !dest.Field(i).IsNil() {
+				dest.Field(i).Set(reflect.Zero(dest.Field(i).Type()))
+			}
+		}
+	}
+}
+
+func wasValueScannedIntoEmbeddedStruct(field *schema.Field, fieldsWithValueMap map[string]bool) bool {
+	if fieldsWithValueMap[field.BindName()] {
+		return true
+	}
+
+	if field.EmbeddedSchema != nil {
+		for _, embeddedField := range field.EmbeddedSchema.Fields {
+			if wasValueScannedIntoEmbeddedStruct(embeddedField, fieldsWithValueMap) {
+				return true
+			}
+		}
+	}
+
+	return false
 }
 
 // ScanMode scan data mode

tests/go.mod

@@ -17,7 +17,7 @@ require (
 require (
 	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/go-sql-driver/mysql v1.8.0 // indirect
+	github.com/go-sql-driver/mysql v1.8.1 // indirect
 	github.com/golang-sql/civil v0.0.0-20220223132316-b832511892a9 // indirect
 	github.com/golang-sql/sqlexp v0.1.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect

tests/scan_test.go

@@ -5,6 +5,7 @@ import (
 	"sort"
 	"strings"
 	"testing"
+	"time"
 
 	"gorm.io/gorm"
 	. "gorm.io/gorm/utils/tests"
@@ -126,7 +127,7 @@ func TestScanRows(t *testing.T) {
 
 	rows, err := DB.Table("users").Where("name = ? or name = ?", user2.Name, user3.Name).Select("name, age").Rows()
 	if err != nil {
-		t.Errorf("Not error should happen, got %v", err)
+		t.Errorf("No error should happen, got %v", err)
 	}
 
 	type Result struct {
@@ -148,7 +149,7 @@ func TestScanRows(t *testing.T) {
 	})
 
 	if !reflect.DeepEqual(results, []Result{{Name: "ScanRowsUser2", Age: 10}, {Name: "ScanRowsUser3", Age: 20}}) {
-		t.Errorf("Should find expected results")
+		t.Errorf("Should find expected results, got %+v", results)
 	}
 
 	var ages int
@@ -158,7 +159,104 @@ func TestScanRows(t *testing.T) {
 
 	var name string
 	if err := DB.Table("users").Where("name = ?", user2.Name).Select("name").Scan(&name).Error; err != nil || name != user2.Name {
-		t.Fatalf("failed to scan ages, got error %v, ages: %v", err, name)
+		t.Fatalf("failed to scan name, got error %v, name: %v", err, name)
+	}
+}
+
+func TestScanRowsNullValuesScanToFieldDefault(t *testing.T) {
+	DB.Save(&User{})
+
+	rows, err := DB.Table("users").
+		Select(`
+			NULL AS bool_field,
+			NULL AS int_field,
+			NULL AS int8_field,
+			NULL AS int16_field,
+			NULL AS int32_field,
+			NULL AS int64_field,
+			NULL AS uint_field,
+			NULL AS uint8_field,
+			NULL AS uint16_field,
+			NULL AS uint32_field,
+			NULL AS uint64_field,
+			NULL AS float32_field,
+			NULL AS float64_field,
+			NULL AS string_field,
+			NULL AS time_field,
+			NULL AS time_ptr_field,
+			NULL AS embedded_int_field,
+			NULL AS nested_embedded_int_field,
+			NULL AS embedded_ptr_int_field
+        `).Rows()
+	if err != nil {
+		t.Errorf("No error should happen, got %v", err)
+	}
+
+	type NestedEmbeddedStruct struct {
+		NestedEmbeddedIntField int
+	}
+
+	type EmbeddedStruct struct {
+		EmbeddedIntField     int
+		NestedEmbeddedStruct `gorm:"embedded"`
+	}
+
+	type EmbeddedPtrStruct struct {
+		EmbeddedPtrIntField   int
+		*NestedEmbeddedStruct `gorm:"embedded"`
+	}
+
+	type Result struct {
+		BoolField          bool
+		IntField           int
+		Int8Field          int8
+		Int16Field         int16
+		Int32Field         int32
+		Int64Field         int64
+		UIntField          uint
+		UInt8Field         uint8
+		UInt16Field        uint16
+		UInt32Field        uint32
+		UInt64Field        uint64
+		Float32Field       float32
+		Float64Field       float64
+		StringField        string
+		TimeField          time.Time
+		TimePtrField       *time.Time
+		EmbeddedStruct     `gorm:"embedded"`
+		*EmbeddedPtrStruct `gorm:"embedded"`
+	}
+
+	currTime := time.Now()
+	result := Result{
+		BoolField:         true,
+		IntField:          1,
+		Int8Field:         1,
+		Int16Field:        1,
+		Int32Field:        1,
+		Int64Field:        1,
+		UIntField:         1,
+		UInt8Field:        1,
+		UInt16Field:       1,
+		UInt32Field:       1,
+		UInt64Field:       1,
+		Float32Field:      1.1,
+		Float64Field:      1.1,
+		StringField:       "hello",
+		TimeField:         currTime,
+		TimePtrField:      &currTime,
+		EmbeddedStruct:    EmbeddedStruct{EmbeddedIntField: 1, NestedEmbeddedStruct: NestedEmbeddedStruct{NestedEmbeddedIntField: 1}},
+		EmbeddedPtrStruct: &EmbeddedPtrStruct{EmbeddedPtrIntField: 1, NestedEmbeddedStruct: &NestedEmbeddedStruct{NestedEmbeddedIntField: 1}},
+	}
+
+	for rows.Next() {
+		if err := DB.ScanRows(rows, &result); err != nil {
+			t.Errorf("should get no error, but got %v", err)
+		}
+	}
+
+	if !reflect.DeepEqual(result, Result{}) {
+		t.Errorf("Should find zero values in struct fields, got %+v", result)
 	}
 }