ASP0023 Ambiguous route warning when targeting .NET 8 and using token [action] or [controller] in [Http*] or [Route] attributes

[Alien21]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When targeting .NET 8 preview 6 and using token [action] or [controller] in [Http*] or [Route] attributes on a controller method, an ASP0023 warning is emitted which is a new behaviour that wasn't observed in .NET 7.

If you ignore the warnings, the code will run and the endpoints can be called and return the expected responses for their respective verbs.

Expected Behavior

No warning generated

Steps To Reproduce

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddControllers();

var app = builder.Build();
app.MapControllers();
app.Run();

[Route("api/[controller]")]
[ApiController]
public class MyController : ControllerBase
{
    [HttpGet("[action]")]
    public IActionResult GetTime() => Ok(DateTime.Now.ToString("HH:mm:ss"));
    
    [HttpGet("[action]")]
    public IActionResult GetDate() => Ok(DateTime.Now.ToString("yyyy-MM-dd"));
}

Exceptions (if any)

No response

.NET Version

8.0.100-preview.6.23330.14

Anything else?

╰─ dotnet --info                                                                                                                                                                           ─╯
.NET SDK:
 Version:   8.0.100-preview.6.23330.14
 Commit:    ba97796b8f

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22621
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\8.0.100-preview.6.23330.14\

.NET workloads installed:
 [wasm-tools]
   Installation Source: SDK 8.0.100-preview.6
   Manifest Version:    8.0.0-preview.6.23329.7/8.0.100-preview.6
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\8.0.100-preview.6\microsoft.net.workload.mono.toolchain.current\WorkloadManifest.json
   Install Type:              Msi
 [wasm-tools-net6]
   Installation Source: SDK 8.0.100-preview.6
   Manifest Version:    8.0.0-preview.6.23329.7/8.0.100-preview.6
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\8.0.100-preview.6\microsoft.net.workload.mono.toolchain.net6\WorkloadManifest.json
   Install Type:              Msi

Host:
  Version:      8.0.0-preview.6.23329.7
  Architecture: x64
  Commit:       5340be2ccc

.NET SDKs installed:
  7.0.306 [C:\Program Files\dotnet\sdk]
  8.0.100-preview.6.23330.14 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.6.23329.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.6.23329.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.0-preview.6.23329.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

[WernerMairl]

Same here with net8.0 RC2.

Assuming that "[action]" is interpreted as literal/constant instead of a expression, and then for sure it isn't unique...

BR
Werner

[Glitched94]

Edited: My example was actually incorrect, the analyzer only identifies matches within the same controller. I've updated the comment to be more accurate, but the info I've added isn't much beyond the initial report.

The behavior is the same regardless of where the [action] part of the route is set. Example below errors as well

[Route("api/[controller]/[action]")]
[ApiController]
public class Controller1 : ControllerBase
{
    [HttpGet("{id:int}")]
    public IActionResult GetMethod1(int id) => Ok();
   
    [HttpGet("{id:int}")]
    public IActionResult GetMethod2(int id) => Ok();
}

[jeffraska]

Analyzer was introduced in PR #45915.
@JamesNK is there chance analyzer behavior will be fixed on .net 8 release?

[martincostello]

If there's a bug in the analyzer and it's patched in servicing, it's not going to make it into the 8.0.0 release at this point.

[JamesNK]

Analyzer was introduced in PR #45915. @JamesNK is there chance analyzer behavior will be fixed on .net 8 release?

No, .NET 8 is locked down for only urgent fixes right now. This is a bug but not a critical one. However, it can be fixed in 8.0.x release later this year or early next year.

I suggest you disable the analyzer in the project file with <NoWarn>ASP0023</NoWarn>:

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

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <NoWarn>ASP0023</NoWarn>
  </PropertyGroup>

</Project>

Or in code:

    [Route("api/[controller]/[action]")]
    [ApiController]
    public class Controller1 : ControllerBase
    {
#pragma warning disable ASP0023 // Route conflict detected between controller actions
        [HttpGet("{id:int}")]
        public IActionResult GetMethod1(int id) => Ok();

        [HttpGet("{id:int}")]
        public IActionResult GetMethod2(int id) => Ok();
#pragma warning restore ASP0023 // Route conflict detected between controller actions
    }

And reenable when the analyzer is fixed.

[Mike-E-angelo]

Woohoo. Thank you for your efforts out there @JamesNK and team. 🙏 Happy Holidays. 🦃