RequestBuilder.BuildUri() returns broken Uri on Thai cultureinfo

[HJLeee]

Hello. One of my clients has reported a bug that occurs only in certain settings.

Environment details

• Programming language: C#
• OS: Linux
• Language runtime version: .NET Core 3.1
• Package version: 1.44 (and after)

Steps to reproduce

1. Run this sample on .NET Core 3.1 + Linux env.

  class Program
  {
      static void Main(string[] args)
      {
          CultureInfo.CurrentCulture = new CultureInfo("th");
          foo();

          CultureInfo.CurrentCulture = new CultureInfo("en-US");
          foo();

      }

      static void foo()
      {
          var baseUriStr = "https://accounts.google.com/o/oauth2/v2/auth";
          var pathStr = "?access_type=offline~";

          var builder = new RequestBuilder()
          {
              BaseUri = new Uri(baseUriStr),
              Path = pathStr
          };

          Console.WriteLine($"{builder.BuildUri().AbsoluteUri}");
          Console.WriteLine($"{pathStr.StartsWith("/")} vs {pathStr.StartsWith("/", StringComparison.OrdinalIgnoreCase)}");
      }
  }

2. Check the result.

https://accounts.google.com/?access_type=offline~
True vs False
https://accounts.google.com/o/oauth2/v2/auth?access_type=offline~
False vs False

This is due to a bug in .NET Core 3.1 inappropriately handling Thai language and luckly it is fixed in .NET 5.
As the sample code shows, it needs to add StringComparison.OrdinalIgnoreCase option to string.StartsWith() to work around the bug.

google-api-dotnet-client/Src/Support/Google.Apis.Core/Requests/RequestBuilder.cs

Line 126 in c6c7e6e

if (path.StartsWith("/"))

I found that .NET runtime code also uses StringComparison.OrdinalIgnoreCase internally for Uri handling.
https://github.com/dotnet/runtime/blob/9cbad65fe68bc518fee67f7d75056ea0651e6221/src/libraries/System.Private.Uri/src/System/Uri.cs#L1915

Thank you.

[amanda-tarafa]

We are discussing this internally. For now I've marked this issue as a question as there's really not a bug in libraries. If anything we'll be applying a workaround for a bug in .NET Core 3.1.

Do you have a reference to an issue in .NET Core 3.1 that we can look at? Our main worry is that if we work around the forward slash comparison, what else can we find down the road that is also not properly handled with Thai culture by .NET?

[HJLeee]

Do you have a reference to an issue in .NET Core 3.1 that we can look at?

Sure. The below link shows there are behavior differences among .NET versions and how to deal with it from .NET developer perspective.

• https://learn.microsoft.com/en-us/dotnet/standard/base-types/string-comparison-net-5-plus

My original post concerns only my circumstances which is .NET 3.1 + Linux with string.StartsWith("/") on Thai culture but you can find other related issues posted on dotnet/runtime repo.
They are not limited to .NET 3.1 but also occurs on other .NET versions.

• String.IndexOf("'") returns incorrect value in Thai culture dotnet/runtime#87939
• string.IndexOf bug when using Thai culture dotnet/runtime#75616
• string.IndexOf() incorrect return value for full stop for Thai culture dotnet/runtime#76137

Also there is an internal discussion about it since 2020 but not yet concluded.

• Improving the developer experience with regard to default string globalization dotnet/runtime#43956

So, some of .NET components like MAUI landed PR like this.

• [core] use StringComparison.Ordinal everywhere dotnet/maui#4988

[amanda-tarafa]

Thanks @HJLeee . See #2542 who should work around your issue.

[amanda-tarafa]

@HJLeee we have released v1.62.1 of the support libraries: Google.Apis.Core, Google.Apis, Google.Apis.Auth, Google.Apis.Auth.AspNetCore3 with the workaround in #2542.

Please make certain you add explicit references to these packages.

I'll be closing this issue now as I believe there's nothing else we can do here, but do leave a comment if you believe otherwise.

[HJLeee]

#2546 looks good. I appreciate for your fast PR landing and release. :)