Buildvana SDK breaks Omnisharp in VS Code

[rdeago]

Buildvana SDK breaks Omnisharp in VS Code

[rdeago]

After some research and quite a few trial and error cycles, during which I managed to fix other, still undiscovered issues (PR incoming BTW), it seems that this is not a problem with Buildvana SDK.

The same issue has been reported in dotnet/vscode-csharp#3766 so it looks like either Omnisharp or MSBuild itself is to blame.

[rdeago]

Some more research revealed that the same problem afflicts all tasks derived from AppDomainIsolatedTask, even built-in tasks such as ResolveComReference, as proved by this comment on Omnisharp's issue.

AppDomainIsolatedTask is a bare minimum ITask implementation; its only distinguishing feature is being decorated with a LoadInSeparateAppDomain attribute, which triggers special behavior in MSBuild's internal TaskLoader class. That special behavior (running the task in a separate AppDomain) seems to prevent Omnisharp from successfully loading the task, although I haven't dug any deeper into it.

Buildvana SDK's ContextIsolatedTask doesn't need any special treatment, because it already creates and uses its own separate AppDomain. So, instead of deriving it from AppDomainIsolatedTask, I made it a subclass of MarshalByRefObject and added a bare minimum ITask implementation.

I tried opening my local Buildvana SDK repo in VS code with a locally-rebuilt SDK. Omnisharp works like a charm. PR incoming.