dotnet-fable demands specific version of dotnet SDK

[et1975]

Description

All the dotnet projects I have so far were built using SDK version 1.0.3 and dotnet-fable 1.0.4 was happy with it. While upgrading to paket-managed dependencies I specified dotnet-fable cli version to be "1.0.*" and it broke the build with the error:

The specified framework 'Microsoft.NETCore.App', version '1.0.5' was not found.

• Check application dependencies and target a framework version installed at:
  /usr/local/share/dotnet/shared/Microsoft.NETCore.App
• The following versions are installed:
  1.0.3
  1.0.4
  1.1.0
  1.1.1
• Alternatively, install the framework version '1.0.5'.

Apparently 1.0.6 version of dotnet-fable imposes this requirement on the SDK version. There's nothing anywhere in my working directory referencing 'Microsoft.NETCore.App', version '1.0.5' , no way to tell what demands it. There's no obvious way to override this either.

For the moment I locked the dotnet-fable version in the project file, but going forward and
considering there's a release of the SDK every month or so:

• is forcing the user to keep up an absolute requirement?

I have newer version of SDK, so clearly this requirement is not even backwards-compatible, meaning running multiple project on different versions is going to be DevOps nightmare.

Repro code

https://github.com/fable-elmish/sample-react-counter

Change the fsproj to use dotnet-fable version="1.0.*" and hope you have the right version of the SDK.

Expected and actual results

Expect it to build as long as F# build succeeds.

Related information

• fable-compiler version: 1.0.6
• fable-core version: n/a
• Operating system: OSX

[alfonsogarciacaro]

OMG, this is crazy. Welcome to the hell of netcore versioning 🔥 dotnet-fable targets netcoreapp1.0. I guess the dependency on the 1.0.5 runtime just comes because I had that runtime installed in my computer when I built it, but I didn't know new patch versions weren't backwards compatible 😡

Please note the runtime and SDK versions are two different things, see here

Unfortunately I'm not sure how to prevent this, maybe @enricosada will be our saviour as always?

On another note, until Paket can manage DotNetCliToolReference items, it's recommended you pin dotnet-fable version to the Fable.Core one in paket.dependencies, as it's done in the templates.

[enricosada]

Workaround (will send PR for fix asap):

• do dotnet -d fable
• will show some diagnostics, find the

  packagedcommandspecfactory: Looking for prefercliruntime file at `C:\Users\e.sada\.nuget\packages\dotnet-fable\1.0.6\lib\netcoreapp1.0\..\..\prefercliruntime`
  

• create that file C:\Users\e.sada\.nuget\packages\dotnet-fable\1.0.6\lib\netcoreapp1.0\..\..\prefercliruntime (empty is ok)

Now things should work

[enricosada]

As a note for posterity.

this affect users with .NET Command Line Tools (1.0.1) (try dotnet --info) using dotnet-fable version 1.0.5 or 1.0.6.

Is ok with .NET Command Line Tools (1.0.4) with any dotnet-fable version, also previous