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Incorrect DateTime Deserialization in Unity (2021.3.16f1) Mono .NET Standard 2.1 #1546
Description
Bug description
When serialize and then deserialize a DateTime objects, sometimes the deserilized version would have a fixed value of "02/07/2106 06:28:15"!
Repro steps
using System;
using MessagePack;
using UnityEngine;
public class MainMenu : MonoBehaviour
{
void Start()
{
for (int i = 0; i < 10; i++)
{
var b = MessagePackSerializer.Serialize(DateTime.Now);
DateTime c = MessagePackSerializer.Deserialize<DateTime>(b);
Debug.Log(c);
}
}
}
above script attached to maincamera of a 2d Scene.
Expected behavior
Deserialized value should be equal to DateTime value before serialization.
Actual behavior
Deserilized value would be DateTime object with value "02/07/2106 06:28:15"
- Version used: 2.4.35
- Runtime: Unity version 2021.3.16f1, Mono .NET Standard 2.1
Activity
[-]Incorrect DateTime Serialization in Unity (2021.3.16f1) Mono .NET Standard 2.1[/-][+]Incorrect DateTime Deserialization in Unity (2021.3.16f1) Mono .NET Standard 2.1[/+]ImanNavidi commentedon Jan 1, 2023
I found that the problem is with deserialization and for specific times..
Still investigating
ImanNavidi commentedon Jan 2, 2023
Following code is causing problem on my system (hopefully!).
https://github.com/neuecc/MessagePack-CSharp/blob/fa0da944a581cf9de241148dc5639d7959886326/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/SafeBitConverter.cs#L16
bitwise operations between byte objects, turned the signed bits and caused the problem.
changing the code to the following solved the problem for me:
am I doing it right?
AArnott commentedon Jan 3, 2023
Are you sure you're comparing apples to apples here? Your
DateTime.Nowvalue will be encoded in UTC time by msgpack (assuming you're using the default resolver), so when it is deserialized it comes out as UTC time, even though the original value was using Local time. Can you try the experiment withUtcNowinstead?ImanNavidi commentedon Jan 4, 2023
I was aware of UTC conversion.
the problem was with the code provided.
simply
would not work as expected for a values greater than 127 (because of sign bits)
ImanNavidi commentedon Jan 5, 2023
I have solved the problem with the multiplication version (code provided above) for myself.
Not sure about the efficiency. If it is efficient, I can create a pull request
AArnott commentedon Jan 6, 2023
I can't reproduce the problem here. Can you pick a value that fails?
Or is this a bug in the mono runtime uniquely?
ImanNavidi commentedon Jan 6, 2023
long.MaxValue or even 1000000000000.
Fix unity+android code for reading an Int64 from memory
cubed-it commentedon Feb 17, 2023
How about a new unitypackage? This is a really nasty issue where you may not immediately recognize the origin. I just stumbled across the issue and it took me an hour to finally get here. I have now copied the changes by hand.
AArnott commentedon Mar 11, 2023
@cubed-it, I guess watch #1562