String.IndexOf("\0") Zero

[my522cn]

Description

Before dotnet5, below code d and e are both 9. But in dotnet5, e is 0. I think it is a bug.

string a = "FT4EVT0DA\0\0\0?\u007f\0\0";
var d = a.IndexOf('\0');
var e = a.IndexOf("\0");

Configuration

• Which version of .NET is the code running on?
• 5.0
• What OS and version, and what distro if applicable?
• Win10 20H2
• What is the architecture (x64, x86, ARM, ARM64)?
• x64

Regression?

Other information

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[teo-tsirpanis]

Hello, .NET 5 started using the ICU globalization libraries on Windows 10 1903 or newer for consistency with other operating systems. This change has unavoidably brought some breaking behavioral changes like this one.

In your case however, if you are simply looking for null characters in a string, an ordinal search would be ideal for you. IndexOf with a character always makes ordinal searches, and you can perform an ordinal search on a string like this:

var e = a.IndexOf("\0", StringComparison.Ordinal);

[ghost]

Tagging subscribers to this area: @dotnet/area-system-runtime
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Before dotnet5, below code d and e are both 9. But in dotnet5, e is 0. I think it is a bug.

string a = "FT4EVT0DA\0\0\0?\u007f\0\0";
var d = a.IndexOf('\0');
var e = a.IndexOf("\0");

Configuration

• Which version of .NET is the code running on?
• 5.0
• What OS and version, and what distro if applicable?
• Win10 20H2
• What is the architecture (x64, x86, ARM, ARM64)?
• x64

Regression?

Other information

Author:	my522cn
Assignees:	-
Labels:	area-System.Runtime, untriaged
Milestone:	-

[ghost]

Tagging subscribers to this area: @tarekgh, @safern
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Before dotnet5, below code d and e are both 9. But in dotnet5, e is 0. I think it is a bug.

string a = "FT4EVT0DA\0\0\0?\u007f\0\0";
var d = a.IndexOf('\0');
var e = a.IndexOf("\0");

Configuration

• Which version of .NET is the code running on?
• 5.0
• What OS and version, and what distro if applicable?
• Win10 20H2
• What is the architecture (x64, x86, ARM, ARM64)?
• x64

Regression?

Other information

Author:	my522cn
Assignees:	-
Labels:	area-System.Globalization, area-System.Runtime, untriaged
Milestone:	-

[tarekgh]

@my522cn please look at the issue #46569 for more details. I am closing this issue but feel free to send any question and we'll be happy to help with.