Microsoft.Extensions.ApiDescription.Server 3.0.0-rc1.19457.4 causes build to fail on macOS

[martincostello]

Describe the bug

Originally found via domaindrivendev/Swashbuckle.AspNetCore#1266 (comment)

When Microsoft.Extensions.ApiDescription.Server is in the dependency tree of an ASP.NET Core 3.0 application, the application fails to build on macOS with the following error:

/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error : System.TimeoutException: Process /Users/travis/build/martincostello/api/.dotnetcli/dotnet timed out after 2 minutes. [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error :    at Microsoft.Extensions.ApiDescription.Tool.Exe.Run(String executable, IReadOnlyList`1 args, IReporter reporter, String workingDirectory, Boolean interceptOutput) [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error :    at Microsoft.Extensions.ApiDescription.Tool.Commands.InvokeCommand.Execute() [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error :    at Microsoft.Extensions.ApiDescription.Tool.Commands.CommandBase.<>c__DisplayClass14_0.<Configure>b__0() [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error :    at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args) [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error :    at Microsoft.Extensions.ApiDescription.Tool.ProgramBase.Run(String[] args, CommandBase command, Boolean throwOnUnexpectedArg) [/Users/travis/build/martincostello/api/src/API/API.csproj]
/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build/Microsoft.Extensions.ApiDescription.Server.targets(62,5): error MSB3073: The command "dotnet "/Users/travis/.nuget/packages/microsoft.extensions.apidescription.server/3.0.0-rc1.19457.4/build//../tools/dotnet-getdocument.dll" --assembly "/Users/travis/build/martincostello/api/src/API/bin/Release/netcoreapp3.0/API.dll" --file-list "obj/API.OpenApiFiles.cache" --framework ".NETCoreApp,Version=v3.0" --output "obj" --project "API" --assets-file "/Users/travis/build/martincostello/api/src/API/obj/project.assets.json" --platform "AnyCPU" " exited with code 1. [/Users/travis/build/martincostello/api/src/API/API.csproj]

The issue can be worked around by setting the following MSBuild property:

<OpenApiGenerateDocuments>false</OpenApiGenerateDocuments>

To Reproduce

Add the following NuGet package reference to an ASP.NET Core 3.0 application which has an API controller and build the application on macOS:

<PackageReference Include="Microsoft.Extensions.ApiDescription.Server" Version="3.0.0-rc1.19457.4" />

Expected behavior

The application builds successfully.

Additional context

This issue appears to only affect macOS, and not Windows or Linux. See this PR for different build behaviours: martincostello/api#212

[mkArtakMSFT]

Thanks for contacting us, @martincostello.
@ryanbrandenburg can you please look into this? Thanks!

[ryanbrandenburg]

This didn't replicate for me, the .json file generated successfully on macOS. There were also more steps than what's listed above to get things set up. What I did:

1. dotnet new webapi
2. Add the reference to Microsoft.Extensions.ApiDescription.Server.
3. Add a reference to Swashbuckle.AspNetCore, Version 5.0.0-rc3.
4. In ConfigureServices add:

services.AddSwaggerGen(c => { c.SwaggerDoc("v1", new OpenApiInfo{ Title="My API", Version = "v1" } ) });

5. In Configure add:

app.UseSwagger();
app.UseSwaggerUI(c => { c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1"); });

In order to investigate further I'll need you to create (as a GitHub repo) a simplified repro project which demonstrates the failure so that I can use it to investigate.

[martincostello]

If you use the repo for the PR linked to in the description, you can see the issue being replicated if you revert the workaround in the final commit of the PR. It’s a very simple project that’s just got some simple resources (like getting the current time).

[ryanbrandenburg]

I was able to reproduce this. My current best guess is that it's actually a CoreFX problem, so we're going to have them take a look at a dump I made of the problem. The gist of it seems to be that the process we launch from within the CLI tool to do the actual document creation "hangs" because the Program.Main function is exited but the process is still open.