в функцию Set добавлена проверка data на nil

pkg/data/data.go

@@ -9,6 +9,8 @@ import (
 
 const DefaultFieldDelimiter = "."
 
+var ErrDataIsNil = errors.New("data is nil")
+
 type DeleteValueType struct{}
 
 var DeleteValue DeleteValueType
@@ -169,6 +171,10 @@ func getPath(field string, delim ...string) []string {
 }
 
 func Set(field string, data, value any, delim ...string) error {
+	if data == nil {
+		return ErrDataIsNil
+	}
+
 	return set(getPath(field, delim...), data, value)
 }
 

pkg/data/data_test.go

@@ -316,6 +316,12 @@ func TestSet(t *testing.T) {
 			[]any{(map[string]any)(nil), map[string]any{"b": "2"}},
 			assert.Error,
 		},
+		{
+			"Set object to nil data",
+			args{"a", nil, "1"},
+			nil,
+			assert.Error,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {