Build servers are my friends

By now I’ve authored at least 10 CI/CD pipelines for different net core projects and debugged pipelines of colleagues a lot. And I really expected that nothing could go wrong for the most basic of the basic pipelines: Do a windows build of my GUI program.

> dotnet restore --runtime win10-x64
> dotnet build {SubProject} --configuration Release --runtime win10-x64 --no-restore
> dotnet publish {SubProject} --configuration Release --runtime win10-x64 --no-restore --no-build --no-self-contained

What do I get? An exe that complains about: Nothing. It just doesn’t start.

So I drop the --no-self-contained: and it works. But the output 88mb instead of 10mb. Which is not acceptable. Now instead of chaining the commands I use just the publish command and drop the --no-restore and --no-build

> dotnet publish {SubProject} --configuration Release --runtime win10-x64 --no-self-contained

AND IT WORKS. So either black magic or dotnet publish without those flags does much more behind the scene than I think it does

Maybe my project is at fault

So let’s try a minimal reproduction:

dotnet version 3.1.403

WhyWonYouWork.csproj

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>netcoreapp3.1</TargetFramework>
    </PropertyGroup>
</Project>

Program.cs

using System;

namespace WhyWontYouWork
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}

You cannot go more basic than this.

> dotnet restore --runtime win10-x64
> dotnet build WhyWontYouWork --configuration Release --runtime win10-x64 --no-restore
> dotnet publish WhyWontYouWork --configuration Release --runtime win10-x64 --no-restore --no-build --no-self-contained
> WhyWontYouWork\bin\Release\netcoreapp3.1\win10-x64\publish\WhyWontYouWork.exe

A fatal error was encountered. The library ‘hostpolicy.dll’ required to execute the application was not found in ‘C:\Program Files\dotnet’.

??????????????????

The files in the folder are

 31718  Nov  1 23:22 WhyWontYouWork.deps.json
  4096  Nov  1 23:22 WhyWontYouWork.dll*
174592  Nov  1 23:22 WhyWontYouWork.exe*
  9356  Nov  1 23:22 WhyWontYouWork.pdb
   185  Nov  1 23:22 WhyWontYouWork.runtimeconfig.json

So let’s try this:

> dotnet publish WhyWontYouWork --configuration Release --runtime win10-x64 --no-self-contained
> WhyWontYouWork\bin\Release\netcoreapp3.1\win10-x64\publish\WhyWontYouWork.exe

Hello World!

The files in the folder of the working build are

   491 Nov  1 23:32 WhyWontYouWork.deps.json         
  4096 Nov  1 23:32 WhyWontYouWork.dll*              
174592 Nov  1 23:32 WhyWontYouWork.exe*              
  9356 Nov  1 23:32 WhyWontYouWork.pdb               
   154 Nov  1 23:32 WhyWontYouWork.runtimeconfig.json

The runtimeconfig.json of the failed build looks like this:

{
    "runtimeOptions": {
        "tfm": "netcoreapp3.1",
        "includedFrameworks": [
            {
                "name": "Microsoft.NETCore.App",
                "version": "3.1.9"
            }
        ]
    }
}

vs from the working one:

{
    "runtimeOptions": {
        "tfm": "netcoreapp3.1",
        "framework": {
            "name": "Microsoft.NETCore.App",
            "version": "3.1.0"
        }
    }
}

And the failed build deps:

{
    "runtimeTarget": {
      "name": ".NETCoreApp,Version=v3.1/win10-x64",
      "signature": ""
    },
    "compilationOptions": {},
    "targets": {
      ".NETCoreApp,Version=v3.1": {},
      ".NETCoreApp,Version=v3.1/win10-x64": {
        "WhyWontYouWork/1.0.0": {
          "dependencies": {
            "runtimepack.Microsoft.NETCore.App.Runtime.win-x64": "3.1.9"
          },
          "runtime": {
            "WhyWontYouWork.dll": {}
          }
        },
        "runtimepack.Microsoft.NETCore.App.Runtime.win-x64/3.1.9": {
          "runtime": {
            "Microsoft.CSharp.dll": {
              "assemblyVersion": "4.0.5.0",
              "fileVersion": "4.700.20.47203"
            },
// + 800 lines more dependencies of "runtimepack.Microsoft.NETCore.App.Runtime.win-x64/3.1.9"

Meanwhile the working builds WHOLE deps

{
    "runtimeTarget": {
      "name": ".NETCoreApp,Version=v3.1/win10-x64",
      "signature": ""
    },
    "compilationOptions": {},
    "targets": {
      ".NETCoreApp,Version=v3.1": {},
      ".NETCoreApp,Version=v3.1/win10-x64": {
        "WhyWontYouWork/1.0.0": {
          "runtime": {
            "WhyWontYouWork.dll": {}
          }
        }
      }
    },
    "libraries": {
      "WhyWontYouWork/1.0.0": {
        "type": "project",
        "serviceable": false,
        "sha512": ""
      }
    }
}

Also that missing ‘hostpolicy.dll’ is listed in the long list of dependencies. So WHAT exactly is the one-liner dotnet publish passing to the restore and build that makes the difference ? I tried reading through the dotnet cli code to see if something jumps out but I just don’t see anything that is suspicious.

After googling around for a while I came across this issue: https://github.com/dotnet/runtime/issues/3569 which doesn’t answer my main question at all: WHY THE FUCK ARE THOSE TWO APPROACHES NOT THE SAME.

dotnet publish is more than the sum of its parts

TOC

Build servers are my friends

Maybe my project is at fault

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