I actually think the problem is this line should have been removed:

Changing Python version would also mean NativeTypeOffset must be regenerated (if present), and currently I see no easy way to detect that scenario. Perhaps NativeTypeOffset should have version embedded and checked somewhere.

@lostmsu Well, that one doesn't do much, I don't see what that would bring. Adding version and ABI flags to the interop classes and comparing against those should be more stable.

@tminka The advice should be to run python setup.py configure.

@filmor I have changed the advice as directed.

@lostmsu Your suggestion works. If Python.Runtime.csproj includes all interopXX.cs files, then an incorrect value of PythonInteropFile does not break the build. This seems like a useful robustness to have, so I added it.

The test failures imply that NativeTypeOffset is in fact not generated on some non-Windows platforms. I'm not sure what to do about that.

It seems to be a temporary fluke, the test failures are identical between this and your other PR, which are unrelated.

Oh @tminka , you meant this failure: f59e5d0

I think this is because you must keep

  <ItemGroup Condition=" '$(PythonInteropFile)' != '' ">	
    <Compile Include="$(PythonInteropFile)" />	
  </ItemGroup>

I believe the file is generated outside src\runtime folder, and thus is not included into default compile items.

I have restored the lines that you mentioned, and the same tests fail. So I don't think that was the problem. Also, if you look at the output of the "Build and Install" step, ubuntu 3.6 prints Creating src/runtime/interop36m.cs but ubuntu 3.8 and 3.9 do not. Therefore they are not generating any interop file. Also, if you read setup.py you will see that it always creates the interop file in src\runtime, so it is not possible for the file to be generated outside src\runtime folder.

Perhaps the reason that no interop file is generated is because sys.abiflags was changed in 3.8 to be an empty string. Indeed, MacOS does not generate an interop file for Python 3.8 either. The reason that the "MacOS, 3.8" build succeeds is that the embedded tests were skipped. Maybe "ubuntu, 3.8" should also skip the embedded tests.