System.BadImageFormatException using tasks in F# 6.0

[Lanayx]

Please provide a succinct description of the issue.

Repro steps

The following test fails in Pulsar.Client repo, fsharpsix branch when built with new msbuild
(Microsoft (R) Build Engine version 17.0.0-preview-21460-01+8f208e609 for .NET)
in runtime (link to failed github action)

System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (0x8007000B)
   at <StartupCode$Pulsar-Client>.$ConsumerImpl.clo@122-84.MoveNext()
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Pulsar.Client.Api.ConsumerImpl`1.wrapPostAndReply[U](Task`1 mbAsyncReply) in D:\Work\Pulsar.Client\src\Pulsar.Client\Internal\ConsumerImpl.fs:line 122
   at Pulsar.Client.Api.ConsumerImpl`1.Pulsar.Client.Api.IConsumer<'T>.SeekAsync(MessageId messageId) in D:\Work\Pulsar.Client\src\Pulsar.Client\Internal\ConsumerImpl.fs:line 1569
   at Pulsar.Client.Internal.ReaderImpl`1.Pulsar.Client.Api.IReader<'T>.SeekAsync(MessageId msgId) in D:\Work\Pulsar.Client\src\Pulsar.Client\Internal\ReaderImpl.fs:line 79
   at Pulsar.Client.IntegrationTests.Reader.basicReaderCheck@35-1.MoveNext() in D:\Work\Pulsar.Client\tests\IntegrationTests\Reader.fs:line 61

which is failing at the start of the following function

    let wrapPostAndReply (mbAsyncReply: Task<ResultOrException<'A>>) =
        task {
            match! mbAsyncReply with
            | Ok msg ->
                return msg
            | Error ex ->
                return reraize ex
        }

When building the solution with old compiler
( Microsoft (R) Build Engine version 16.10.2+857e5a733 for .NET Framework )
I'm getting build errors, they can be observed in github actions

I suspect this might be the issue

Unfortunately I couldn't reproduce it on a simpler case for now, maybe later or someone else will help

Steps to run integration tests:

1. Start Pulsar cluster (assuming Docker desktop is installed)

git clone https://github.com/fsharplang-ru/pulsar-client-dotnet
git checkout fsharpsix
cd tests\compose\standalone
docker-compose up

Wait about 2 minutes until the messages flow in console stops (you'll see the message 'Transaction coordinator metadata setup success')

2. Run integration tests

dotnet build
cd tests\IntegrationTests
dotnet run

Expected behavior

The test passes successully when build with both old and new compiler, i.e. it should just work like TaskBuilder.fs worked. (develop branch in Pulsar.Client repo)

Actual behavior

When build with new compiler tests fail in runtime
When build with old compiler code doesn't compile

Known workarounds

Not to upgrade to 6.0

Related information

• Windows 10
• Library is built as .NET Standard 2.0
• Jetbrains Rider

[dsyme]

@gsomix Could you write the repro steps? Also so I need OSX/Ubuntu to repro or can I do this on Windows?

I tried the following on Windows so far

git clone https://github.com/fsharplang-ru/pulsar-client-dotnet
cd pulsar-client-dotnet
dotnet tool restore
dotnet restore
dotnet build
git checkout fsharpsix
dotnet restore
dotnet build
cd tests\UnitTests
dotnet test
dotnet test -c Release

and no problems so far except these warnings which you reported separately in #12190

E:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 4 in table 'itycons' of assembly 'Pulsar.Client, Version=2.8.1.0, 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:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\FsharpExamples.fsproj]
E:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 5 in table 'itycons' of assembly 'Pulsar.Client, Version=2.8.1.0, 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:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\FsharpExamples.fsproj]
E:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\unknown(1,1): warning FS3186: An error occurred while reading the F# metadata node at position 6 in table 'itycons' of assembly 'Pulsar.Client, Version=2.8.1.0, 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:\GitHub\dsyme\pulsar-client-dotnet\examples\FsharpExamples\FsharpExamples.fsproj]

[gsomix]

@dsyme Do you mean @Lanayx? It seems integration tests fail, not unit ones. I tried to make minimal repro, but not succeed.

[dsyme]

@dsyme Do you mean @Lanayx? It seems integration tests fail, not unit ones. I tried to make minimal repro, but not succeed.

Yes, thanks

[Lanayx]

@dsyme I couldn't create a repro with simple case :( To run integration tests you need to setup pulsar cluster by going to the tests\compose\standalone\ folder and running docker-compose up (assuming you have docker desktop installed), it will need about 8Gb of RAM

I've updated repro steps

[dsyme]

Perhaps an exception is being raised elsewhere, then caught, then re-raised, and the problem is not with wrapPostAndReply

[Lanayx]

No the execution doesn't reach there. I've modified the method to be

And it fails with the same exception, if I replace task builder with Task.FromResult as in commented code it works

[Lanayx]

Just made another observation, if I change the method to

    let wrapPostAndReply (mbAsyncReply: Task<ResultOrException<unit>>) =
        task {
            match! mbAsyncReply with
            | Ok msg ->
                return msg
            | Error ex ->
                return reraize ex
        }

e.g. 'A replaced with unit then there is no error

[gsomix]

@dsyme @Lanayx OK, first successful attempt of minimal repro.

open System
open System.Runtime.ExceptionServices
open System.Threading.Tasks

let reraize<'a> ex =
    (ExceptionDispatchInfo.Capture ex).Throw()
    Unchecked.defaultof<'a>

type internal ResultOrException<'T> = Result<'T, exn>

type ConsumerImpl<'T>() =
    let wrapPostAndReply (mbAsyncReply: Task<ResultOrException<'A>>) =
        task {
            match! mbAsyncReply with
            | Ok msg ->
                return msg
            | Error ex ->
                return reraize ex
        }

    member this.SeekAsync() =
        task { return Ok () } 
        |> wrapPostAndReply 

[<EntryPoint>]
let main args = 
    let consumer = ConsumerImpl()
    consumer.SeekAsync() |> ignore
    0

[gsomix]

And even smaller repro. Please note the both generic parameters 'T and 'A are crucial for BadImageFormatException.

open System.Threading.Tasks

type Issue12189<'T>() =
    let run (computation: Task<'A>) =
        task { return! computation }

    member _.Run() =
        run (Task.FromResult(42))

[<EntryPoint>]
let main args = 
    let tmp = Issue12189()
    tmp.Run() |> ignore
    0

[dsyme]

Thank you, I can see the fix that's needed

[dsyme]

Fixed by #12195