Normal builds still run under devenv.exe in VS 16.0 Pre2

[davkean]

From @jeromelaban on January 24, 2019 13:23

Steps to reproduce

When build this solution, and more specifically this project under visual studio, the following message appear:

1>------ Build started: Project: Uno.UI (Uno.UI\Uno.UI), Configuration: Debug Any CPU ------
1>Building target framework: xamarinmac20
1>Building target framework: xamarinios10
1>Building target framework: net46
1>Building target framework: netstandard2.0
1>src\SourceGenerators\Uno.UI.Tasks\Content\Uno.UI.Tasks.targets(53,5): warning : The Uno.UI.Tasks build task is running under devenv.exe you will have to restart Visual Studio to rebuild it.
1>Done building project "Uno.UI.csproj".
1>src\SourceGenerators\Uno.UI.Tasks\Content\Uno.UI.Tasks.targets(77,5): warning : The Uno.UI.Tasks build task is running under devenv.exe you will have to restart Visual Studio to rebuild it.
1>Done building project "Uno.UI.csproj".

This message is produced by this task to warn the user of a devenv.exe locked task.

I tried reproducing using a smaller sample, but could not get it.

Environment data

msbuild /version output:

C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview>msbuild /version
Microsoft (R) Build Engine version 16.0.360-preview+g9781d96883 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

16.0.360.33175

OS info:

Microsoft Windows [Version 10.0.17134.472]
(c) 2018 Microsoft Corporation. All rights reserved.

Copied from original issue: dotnet/msbuild#4095

[davkean]

I can repro this. We're definitely asking for an OutOfProc build here, so not sure why we're being pulled in proc. Investigating.

[davkean]

Okay, I've got it down to:

    <MSBuild Projects="$(MSBuildProjectFile)"
             Targets="_InnerUnoResourcesGeneration_Assets"
             BuildInParallel="true"
             Properties="Configuration=$(Configuration);Platform=$(Platform);Dummy2=true">
      <Output TaskParameter="TargetOutputs" ItemName="UnoRetargetedAssetsOutput" />
    </MSBuild>

The original build request to build the project was run out-of-proc, but it appears to service the above request with an in-proc node that was running for something else. I would have expected this to respect the NodeAffinity of the original request. Started a thread with MSBuild folks.

[davkean]

@jeromelaban What's the reason you are adding the dummy global property?

[jeromelaban]

@davkean It's was a guess about trying to really spawn another msbuild nodes based on the documentation that says:

When you pass properties to the project through the Properties parameter, MSBuild creates a new instance of the project even if the project file has already been loaded.

But it did not seem to change much, and I did not remove it. That being said, in the latest master of Uno, I've removed the sub-msbuilds (it caused me others issues, and did not fix this issue), and the top level msbuild is still running in devenv.exe: https://github.com/nventive/Uno/blob/ab1e38a5c0d681247875f0995df85228d0459717/src/SourceGenerators/Uno.UI.Tasks/Content/Uno.UI.Tasks.targets#L31

[davkean]

Are you saying its unrelated to the MSBuild call above?

[jeromelaban]

It looks like it yes, but it devenv.exe is selected more often if the MSBuild above is defined.

[davkean]

@jeromelaban Just want to make sure you are verifying this using the "warning appearing in the Output window" and not another mechanism to rule out known/expected in-proc usage.

[jeromelaban]

@davkean Just using this task at this location, nothing else fancy.