InstallDotNetCore mixes x64 and x86 versions of .NET Core in the same install root - causes dotnet.exe to crash

[natemcmaster]

Attempting to update to use the new runtimes install feature. The InstallDotNetCore runtimes target is mixing x64 and x86 versions in the same installation root. This breaks .NET Core for obvious reasons - you can mix CPU architectures for native binaries.

Repro:

1. Clone https://github.com/natemcmaster/AspNetCore-Tooling/tree/dotnet
2. Run build.cmd

cc @chcosta

[chcosta]

What is your expectation?

[natemcmaster]

I would expect the installer to know which architecture it is installing, and not to mix bitness. You cannot mix x86 and x64 in the same installation. It causes .NET Core crash with errors like

##[error]dotnet.exe : Failed to load the dll from 
##[error][F:\workspace\_work\1\s\.dotnet\host\fxr\3.0.0-preview6-27708-04\hostfxr.dll], HRESULT: 0x800700C1

[chcosta]

Cool, that makes sense, I wasn't certain if you were proposing something else.

Obviously, the immediate workaround would be to specify "dotnet/x64".

It seems that the initial sdk install script runs in your current machine environment

PROCESSOR_ARCHITECTURE AMD64

but when you are installing the runtimes, you are running under the WoW

PROCESSOR_ARCHITEW6432 AMD64
PROCESSOR_ARCHITECTURE x86

I completely agree that these should be consistent.

[chcosta]

Looking into this

[natemcmaster]

I think MSBuild.exe is the problem here. I'm only seeing this when building on Windows with MSBuild.exe, which runs as x86.

[chcosta]

FYI @tmat

[chcosta]

I'm not a huge fan of this thought, but I suppose, when the installed msbuild is your build engine, we could use an msbuild process to install the sdk as well.

[tmat]

I'm not sure I understand the issue. Is the install script selecting the bitness based on the bitness of the process it runs it? I think we should always default to 64-bit Core CLR if the bitness is not specified.

[chcosta]

Yes, if the architecture is not specified then we don't default one and "dotnet-install.ps1" auto selects an architecture based on the architecture of the process. We could easily default to x64 instead.

[tmat]

Yes, let's do that. But only if we are not on ARM.

System.Runtime.InteropServices.RuntimeInformation.OSArchitecture == X86 | X64

Not sure how ARM works. Will Core CLR ship 32-bit version on ARM? Does Windows have WoW on ARM? If so then probably also want ARM64 to be the default if OSArchitecture == ARM | ARM64.