.net core - NET 5.0 null char handled differently

Question

When re-targeting code from .NET Core 3.1 to .NET 5.0 I discovered the following quirk in a .NET Core 3.x supplied USB DLL interface code.

.NET Core 3.x interprets "" as the string null character '' as in

String.IndexOf("")

, whilst .NET 5.0 does not.

This string null character usage also noted in Trim not working on null characters for String.Replace

Not sure if the above target difference Microsoft intended or not?

static void Main(string[] args)
        {            
            byte[] testBytes = { 0x41, 0x42, 0x43, 0x0, 0x0, 0x0, 0x0, 0x0 }; // ABC
            string testString = Encoding.ASCII.GetString(testBytes);

            int ns = testString.IndexOf("");  // .Net Core 3.x = 3 - .Net 5.0 = 0
            int nc = testString.IndexOf('');  // .Net Core 3.x = 3 - .Net 5.0 = 3

            Console.WriteLine(string.Format("testString={0}, IndexOf: null string = {1:d} null character = {2:d}", testString, ns, nc));
            Console.ReadKey();
        }

question from:https://stackoverflow.com/questions/65837857/net-5-0-null-char-handled-differently

Answer 1

Waitting for answers