FXVersion.TryParse fails to parse version on Thai culture

Problem

Steps to reproduce, on UNIX machine:

LANG=th_TH.UTF-8  dotnet new

this will print: https://gist.github.com/DavidKarlas/29a0749d371be2858ea629a3c66d26fb

Unfortunately on Windows its not so easy to reproduce, but I have this example:

CultureInfo.CurrentCulture = new CultureInfo("th-TH");
Console.WriteLine("55.66.77.88".IndexOf("."));

Which prints 0 instead of 2. And this is where FXVersion parsing fails: https://github.com/dotnet/sdk/blob/a5bda50/src/Resolvers/Microsoft.DotNet.MSBuildSdkResolver/FXVersion.cs#L237 because it tries to parse empty string.

I just want to add this is not just dotnet new problem, similar issue can be reproduced with LANG=th_TH.UTF-8 dotnet build which will print https://gist.github.com/DavidKarlas/a16d14224ad993e71f2b45a0b2103015

And I believe it will also be problem on Windows when user has Thai(or some other similar culture set) as Windows language/culture.

Solution

Use .IndexOf('.', , StringComparison.Ordinal).

[danmoseley]

@wli3 you should enable CA1307 and CA1309 (at least locally) to look for other cases https://github.com/dotnet/docs/issues/21249

[wli3]

Ah, sorry, I thought it was by design. Reopening