Warning FS3186 when writing/referencing a 'DependencyManager'

[matthid]

git clone git@github.com:fsharp/FAKE.git
git checkout 6a4902e41bccfcfac0dbf8a045b798d3bb28f029
dotnet build src/app/fake-cli

Expected behavior

Builds without FS3186

Actual behavior

E:\Projects\FAKE\src\app\Fake.Runtime\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 1 in table 'itycons' of assembly 'Fake.Core.DependencyManager.Paket, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using. [E:\Projects\FAKE\src\app\Fake.Runtime\Fake.Runtime.fsproj]
E:\Projects\FAKE\src\app\Fake.Runtime\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 0 in table 'ivals' of assembly 'Fake.Core.DependencyManager.Paket, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using. [E:\Projects\FAKE\src\app\Fake.Runtime\Fake.Runtime.fsproj]
E:\Projects\FAKE\src\app\fake-cli\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 1 in table 'itycons' of assembly 'Fake.Core.DependencyManager.Paket, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using. [E:\Projects\FAKE\src\app\fake-cli\fake-cli.fsproj]
E:\Projects\FAKE\src\app\fake-cli\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 0 in table 'ivals' of assembly 'Fake.Core.DependencyManager.Paket, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using. [E:\Projects\FAKE\src\app\fake-cli\fake-cli.fsproj]

Known workarounds

<NoWarn>FS3186</NoWarn>

Description

What we try to do is to workaround #8663 but now hit the next problem. Our test suite fails because this warning starts popping up everywhere.
Our idea was to write a 'dummy' dependency manager which doesn't error but ignores all #r "paket" references (to unblock ourself).
To simplify deployment we just added a reference to this dependency manager to Fake.Runtime and fake-cli because then we can assume that the dependency manager is "always" deployed with FAKE (which looks like an obvious solution).

But now this warning appears in several places:

1. When compiling Fake.Runtime and fake-cli (reported above)
2. It appears again when we compile scripts via FCS (at runtime), the only thing changed is that we added --compilertool: and --langversion:

For 1. we can add <NoWarn>FS3186</NoWarn>. For 2. we currently try with --nowarn:3186 but we couldn't get rid of it yet.

EDIT: It seems in FCS-API --nowarn is just not supported at all, so we now just filter the warning afterwards.

The code we use is this: https://github.com/fsharp/FAKE/blob/6a4902e41bccfcfac0dbf8a045b798d3bb28f029/src/app/Fake.Core.DependencyManager.Paket/PaketDependencyManager.fs#L3-L56

EDIT: I hope to filter this warning it not hiding some underlying issue with the approach, please advise :)

Related information

• Operating system: Windows 10
• .NET Runtime kind (.NET Core, .NET Framework, Mono): .Net Core
• Editing Tools (e.g. Visual Studio Version, Visual Studio) : Visual Studio 2019

Related: #7881 #6140

/cc @baronfel

[dsyme]

This error usually indicates mismatched assemblies. It would be good to have a much smaller repro to narrow down if that is not the case. I'd be very surprised if it's anything specifically to do with dependency managers

[dsyme]

We suppressed the specific harmless warning a while back, and as mentioned above the warning usually indicated mismatched assemblies. As a result I will close this.