PublishTrimmed should respect PublishSelfContained

Description

When publishing a trimmed app, I am currently getting an error:

Microsoft.NET.ILLink.targets(196,5): error NETSDK1102: Optimizing assemblies for size is not supported for the selected publish configuration. Please ensure that you are publishing a self-contained app. [C:\DotNetTest\SelfContainedTest\SelfContainedTest.csproj]

Even though I’m setting PublishSelfContained=true in my .csproj. I am also setting SelfContained=false because I don’t want all of the runtime copied into my build output directory. I have many applications that I’m publishing (test apps in dotnet/aspnetcore) and each application is taking up ~100 MB in the bin directory. This is unnecessary bloat.

Reproduction Steps

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <PublishTrimmed>true</PublishTrimmed>
    <PublishSelfContained>true</PublishSelfContained>
    <RuntimeIdentifier>win-x64</RuntimeIdentifier>

    <!-- Set SelfContained=false to prevent the whole runtime from being copied into the build output directory -->
    <SelfContained>false</SelfContained>
  </PropertyGroup>

</Project>

Running dotnet msbuild /t:Publish on that project will fail. It will also fail just for:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <PublishTrimmed>true</PublishTrimmed>
    <PublishSelfContained>true</PublishSelfContained>
  </PropertyGroup>

</Project>

Expected behavior

I expect both apps above to publish successfully.

Actual behavior

Both of them produce the above error.

Regression?

No response

Known Workarounds

Explicitly specify SelfContained=true, but that causes bloat (will eventually be GBs) in my bin directory.

Configuration

No response

Other information

No response

[nagilson]

PublishSelfContained does not work with MSBuild publish, you need to do dotnet publish or forward the property _IsPublishing to MSBuild publish.

[nagilson]

That seems like a mistake.

@eerhardt I hear you. We tried very hard to get it to work for MSBuild publish. It also doesn’t work inside of VS outside of the context of running a dotnet publish.

There are several reasons we landed here. We could technically create some logic in MSBuild to make it work, but it wouldn’t work very well. Adding this to MSBuild would break several key philosophies of MSBuild. One of the problems is that people need to be able to write their own custom publish targets or call the Publish target in their build whenever. We don’t know at the very beginning of the build if someone is going to inject a publish target. But we need the _IsPublishing property to be defined by the beginning of the build/publish, as Configuration depends on it as well as properties like PublishSelfContained and PublishRuntimeIdentifier, and for some of these cases any time before the beginning of the build/publish is too late for it to work. @rainersigwald would be able to provide better context.

One of the only ways (if the only) to get around that is to run the build/publish twice, so you can see in the 1st time if publish is ever invoked and commmunicate that to the 2nd run. But that’s pretty bad.

If we want users to forward/check/set that property, we should give it an official name without an _ at the front

This is a good suggestion and we could do that. But it sounds like there are problems even if that’s used, which is unfortunate. I am trying to think if there is any other solution for this scenario.