Caching issue with Owin self host

[dtchepak]

Sorry for the vague report. I have a fake script that starts up a simple web server. The first time I run it everything is fine, but subsequent times I get:

System.MissingMemberException: The server factory could not be located for the given input: Microsoft.Owin.Host.HttpListener
   at Microsoft.Owin.Hosting.Engine.HostingEngine.ResolveServerFactory(StartContext context)
   at Microsoft.Owin.Hosting.Engine.HostingEngine.Start(StartContext context)
   at Microsoft.Owin.Hosting.WebApp.StartImplementation(IServiceProvider services, StartOptions options, Action`1 startup)
   at FSI_0005.Build.clo@16.Invoke(Unit _arg1)
   at Fake.TargetHelper.runSingleTarget(TargetTemplate`1 target) in C:\code\fake\src\app\FakeLib\TargetHelper.fs:line 489

If I disable caching using fake.exe build.fsx web -nc it works all the time. I am using FAKE 4.23. Not sure if this is related to the issue described here, but that suggested fix didn't resolve it for me.

---

Fake script:

#I @"packages/build/FAKE/tools"
#r "FakeLib.dll"
#r @"packages/build/Owin/lib/net40/Owin.dll"
#r @"packages/build/Microsoft.Owin/lib/net45/Microsoft.Owin.dll"
#r @"packages/build/Microsoft.Owin.Hosting/lib/net45/Microsoft.Owin.Hosting.dll"
#r @"packages/build/Microsoft.Owin.Host.HttpListener/lib/net45/Microsoft.Owin.Host.HttpListener.dll"
#r @"packages/build/Microsoft.Owin.StaticFiles/lib/net45/Microsoft.Owin.StaticFiles.dll"
#r @"packages/build/Microsoft.Owin.FileSystems/lib/net45/Microsoft.Owin.FileSystems.dll"

open Fake
open Owin
open Microsoft.Owin.Hosting
open System

// Based on:
//   http://odetocode.com/blogs/scott/archive/2014/02/10/building-a-simple-file-server-with-owin-and-katana.aspx

Target "web" <| fun _ ->
    use app = WebApp.Start("http://localhost:8080", fun builder -> builder.UseFileServer(false) |> ignore)
    printfn "Started web server on 8080"
    printfn "Press any key exit."
    Console.ReadKey() |> ignore
    app.Dispose()

RunTargetOrListTargets ()

Paket dependencies to get the fake script to work:

source https://www.nuget.org/api/v2/
framework >= net461
group Build
  source https://www.nuget.org/api/v2/
  nuget FAKE
  nuget Microsoft.Owin.SelfHost
  nuget Microsoft.Owin.StaticFiles

[forki]

/cc @matthid

[matthid]

Nice find!
Should be fixed now. took me a while to figure this one out so thanks @dtchepak for the easy repro!