Ionide-vscode-fsharp: Ionide removes LangVersion preview from project file upon loading solution

[MikaelUmaN]

Describe the bug
Ionide removes LangVersion preview from project file upon loading solution

To Reproduce
Steps to reproduce the behaviour:

1. Create project using net 5 preview sdk
2. Add

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <LangVersion>preview</LangVersion>
  </PropertyGroup>

1. Reload solution/project
2. Try to compile/run

Expected behaviour
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Environment (please complete the following information):

• OS: Linux container running using WSL2 in Windows
• Ionide version: 4.16.0
• VSCode version: 1.48.2
• dotnet SDK version: dotnet sdk 5 preview 8

Additional context

Not a huge problem, but I imagine it is an easy fix.

[open-collective-bot[bot]]

Hey @MikaelUmaN :wave:,

Thank you for opening an issue. We will get back to you as
soon as we can. Also, check out our OpenCollective and consider
backing us.

https://opencollective.com/ionide

PS.: We offer backer support for all backers. Don't forget to add backer label when you start backing us :smile:

[witoldsz]

I have the same issue, but not when loading project, but when I add new source file using GUI (_AddFileAbove_/_AddFileBelow_). It adds the file AND removes the <LangVersion>preview</LangVersion> from the fsproj.

[piaste]

It doesn't just remove LangPreview ... it removes _everything_ except the Compile and TargetFramework XML tags.

Before:

<?xml version="1.0" encoding="utf-8"?>
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <DefineConstants>CLIENT</DefineConstants>
    <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <WarningLevel>5</WarningLevel>
    <OtherFlags>$(OtherFlags) --warnon:1182</OtherFlags>
    <NoWarn>FS0052</NoWarn>
  </PropertyGroup>
  <ItemGroup>
    <Compile Include="../../shared/shared.fs" />
    <Compile Include="api.fs" />
    <Compile Include="model.fs" />
    <Compile Include="view.fs" />
  </ItemGroup>
  <Import Project="..\..\.paket\Paket.Restore.targets" />
</Project>

After adding test.fs via right-click menu:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <Compile Include="../../shared/shared.fs" />
    <Compile Include="api.fs" />
    <Compile Include="model.fs" />
    <Compile Include="view.fs" />
    <Compile Include="test.fs" />
  </ItemGroup>
  <Import Project="..\..\.paket\Paket.Restore.targets" />
</Project>

[baronfel]

IIRC this is because of how the forge tool changes the project files. ionide 5 isn't planning on using forge so this issue will just go away naturally.

[Krzysztof-Cieslak]

Should be fixed with 5.0