dotnet muxer reports JSON syntax error when global.json is saved in UTF8+BOM

Steps to reproduce

1. Save global.json in utf8 with byte order mark.
2. dotnet build

Expected behavior

dotnet build shows no errors

Actual behavior

A JSON parsing exception occurred: * Line 1, Column 2 Syntax error: Malformed token

Environment data

dotnet --version output:

A JSON parsing exception occurred: * Line 1, Column 2 Syntax error: Malformed token
1.0.0-beta-002171

[gkhanna79]

This can be looked into fixing for future update - UTF8 is what we support (or lack of BOM). This can be called out in Release notes.

For UTF16 issue fix in a future update, please file a new issue and assign to @schellap

[naamunds]

@gkhanna79 I just ran into this issue with a global.json that has a UTF-16 BOM.

I’m testing .NET on a Windows Nano Server container, so I used PowerShell’s Out-File cmdlet to create the global.json file, which appears to use UTF-16 by default.

I was able to work around the issue by removing the BOM by using [IO.File]::WriteAllText. I also verified that using a UTF-8 BOM is another workaround, e.g. by using Out-File -Encoding utf8.

I’m wondering if it would be worth fixing this issue for UTF-16 in addition to UTF-8, because I think people might run into it, especially because the error message does not make it obvious what the problem is.

cc: @dleeapho @MichaelSimons