System.Linq.AsyncEnumerable package build reference error

[BryanAldrich]

Description

Adding a reference to System.Linq.AsyncEnumerable (from System.Linq.Async) results in the following error.
1>C:\Users\baldrich\source\Lib-git\lib\AdminUtil.cs(74,20,74,75): error CS0012: The type '(, )' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.ValueTuple, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.

My project targets .net 472 and that specific ValueTuple package has no matching dll (by design). The ValueTuple was built into framework 471 and later.

Please provide an additional target framework of net471 so nuget will resolve and use that instead of the 462 build.

Reproduction Steps

Make a new project and target .net 472.
Add a reference to this System.Linq.AsyncEnumerable and ValueTuple.
Add any class/method with a links/reference to the Index() extension method.

testLinqAsyncAndValueTuple.zip

Expected behavior

Compilation.

Actual behavior

Compile error (and somewhat vague, but accurate none-the-less).

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

[huoyaoyuan]

Your example isn't compilable, using Index() method that doesn't exist in .NET Framework. I can't reproduce the issue by using compilable methods like First().

[BryanAldrich]

My mistake on the code, if it reads:
b.ToAsyncEnumerable().Index();
the it should compile in all environments. Index is part of the AsyncEnumerable package even for the .net framework.

Even without that visual studio reports both issues.

[huoyaoyuan]

I can reproduce this now. The workaround is to add <Referece Include="System.ValueTuple" /> to your project file.

However, I think the problem is in System.ValueTuple package, not another package referencing it. Adding package reference to System.ValueTuple should bring the in-box version of ValueTuple.

[huoyaoyuan]

This is effectively a duplicate of dotnet/maintenance-packages#243.

[BryanAldrich]

I can reproduce this now. The workaround is to add <Referece Include="System.ValueTuple" /> to your project file.

However, I think the problem is in System.ValueTuple package, not another package referencing it. Adding package reference to System.ValueTuple should bring the in-box version of ValueTuple.

I kinda fixed it in #121828 PR by adding net47 to the build target and excluding the package as necessary.

This is effectively a duplicate of dotnet/maintenance-packages#243.

Yeah, it is, weird that they included a ref assembly for 47, but explicitly removed it for 471. Sigh.

[BryanAldrich]

I know my prior PR said to discuss it here, I was aiming to prep the PR and bring it out later if needbe, but turns out, a draft isn't private like I thought.

PR #122891 adds net47 dynamically to the targetFrameworks of affected libraries to prevent the build from requiring any ValueTuple reference. This could be fixed by resolving upstream, or changing the 4.6.1 value of ValueTuple to a prior onewhich includes a ref assembly for all versions instead of only 4.7