fix issue in SliceMap/Maps for package gconv when nil value in ma…

…p of slice item (#2857)

util/gconv/gconv_map.go

@@ -259,11 +259,17 @@ func doMapConvertForMapOrStructValue(in doMapConvertForMapOrStructValueInput) in
 				mapKeyValue = reflectValue.MapIndex(k)
 				mapValue    interface{}
 			)
-			if mapKeyValue.IsZero() {
-				// in case of:
-				// exception recovered: reflect: call of reflect.Value.Interface on zero Value
-				mapValue = reflect.New(mapKeyValue.Type()).Elem()
-			} else {
+			switch {
+			case mapKeyValue.IsZero():
+				if mapKeyValue.IsNil() {
+					// quick check for nil value.
+					mapValue = nil
+				} else {
+					// in case of:
+					// exception recovered: reflect: call of reflect.Value.Interface on zero Value
+					mapValue = reflect.New(mapKeyValue.Type()).Elem().Interface()
+				}
+			default:
 				mapValue = mapKeyValue.Interface()
 			}
 			dataMap[String(k.Interface())] = doMapConvertForMapOrStructValue(

util/gconv/gconv_z_unit_slice_test.go

@@ -10,6 +10,8 @@ import (
 	"testing"
 
 	"github.com/gogf/gf/v2/container/gvar"
+	"github.com/gogf/gf/v2/database/gdb"
+	"github.com/gogf/gf/v2/encoding/gjson"
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/test/gtest"
 	"github.com/gogf/gf/v2/util/gconv"
@@ -457,3 +459,18 @@ func Test_EmptyString_To_CustomType(t *testing.T) {
 		t.Assert(len(req.Types), 0)
 	})
 }
+
+func Test_SliceMap_WithNilMapValue(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var (
+			list1 = []gdb.Record{
+				{"name": nil},
+			}
+			list2 []map[string]any
+		)
+		list2 = gconv.SliceMap(list1)
+		t.Assert(len(list2), 1)
+		t.Assert(list1[0], list2[0])
+		t.Assert(gjson.MustEncodeString(list1), gjson.MustEncodeString(list2))
+	})
+}