Using Npgsql 5.0.7 via nuget on .NET 4.8 gives MissingMethodException in ChannelReader

Exception:

Method not found: 'System.Threading.Tasks.ValueTask`1<Boolean> System.Threading.Channels.ChannelReader`1.WaitToReadAsync(System.Threading.CancellationToken)'.

Stacktrace:

   at Npgsql.ConnectorPool.<>c__DisplayClass38_0.<<Rent>g__RentAsync|0>d.MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start[TStateMachine](TStateMachine& stateMachine)
   at Npgsql.ConnectorPool.<>c__DisplayClass38_0.<Rent>g__RentAsync|0()
   at Npgsql.ConnectorPool.Rent(NpgsqlConnection conn, NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken)
   at Npgsql.NpgsqlConnection.<>c__DisplayClass41_0.<<Open>g__OpenAsync|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Npgsql.NpgsqlConnection.Open()
   at SD.LLBLGen.Pro.Gui.Controls.WizardPages.MetaDataRetrievalWizard_Step_ConnectionData.TestConnectionData(Boolean showSuccess) in C:\MyProjects\VS.NET Projects\LLBLGen Pro v5.9\Designer\Gui\Controls\WizardPages\MetaDataRetrievalWizard_Step_ConnectionData.cs:line 245

It’s in my driver, where I obtain the factory using NpgsqlFactory.Instance as I now directly reference the Nuget package. I compile against 4.8 (against 4.7.2 same issue). I copy all necessary files to the output folder, app using the driver is running on .net 4.8, I checked. All I do is obtaining a connection from the factory and then call Open.

I am using this route because Npgsql doesn’t ship an msi anymore so I have to reference the Npgsql package directly to make my users not have to fight where to get the files.

I have no idea what to do nor what I’m doing wrong. It looks like I have to reference another package somewhere but which one is a blur to me.

[roji]

OK, took a look.

After building everything successfully, running NpgsqlRepro.exe failed with:

Could not load file or assembly 'System.Runtime.CompilerServices.Unsafe, Version=4.0.4.1, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Looking at the actual System.Runtime.CompilerServices.Unsafe.dll deployed in Drivers\PostgreSQL, it had a version of 6.0.0, so I amended the binding redirects. When that didn’t work, I noticed that the <dependentAssembly> directives are outside of the <assemblyBinding> node - so I moved them in. At this point the program connected, but threw another runtime binding redirect exception for System.Text.Json, after I added that everything worked…

[roji]

There already was a 6-month gap there, I’d like to make sure this gets closed this time 😉