Incorrect Open API doc generated when branching request execution pipeline

[alinia]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When I branch request execution pipeline like this:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapOpenApi();
app.Map(
    "/branch1",
    b =>
    {
        b.UseRouting();
        b.UseEndpoints(e => e.MapGet("say-hello", () => "Hello from branch1"));
    }
);

app.Map(
    "/branch2",
    b =>
    {
        b.UseRouting();
        b.UseEndpoints(e => e.MapGet("say-hello", () => "Hello from branch2"));
    }
);


app.Run();

The generated Open API doc contains only one path instead of two and with the wrong path:

{
  "openapi": "3.0.1",
  "info": {
    "title": "TestApplication | v1",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:5013"
    }
  ],
  "paths": {
    "/say-hello": {
      "get": {
        "tags": [
          "TestApplication"
        ],
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "string"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": { },
  "tags": [
    {
      "name": "TestApplication"
    }
  ]
}

Expected Behavior

I expect the Open API document to contain two paths one for each branch.

Steps To Reproduce

https://github.com/alinia/test-application/

Exceptions (if any)

No response

.NET Version

9.0.102

Anything else?

.NET SDK:
Version: 9.0.102
Commit: cb83cd4923
Workload version: 9.0.100-manifests.43af17c7
MSBuild version: 17.12.18+ed8c6aec5

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.3
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.102/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.1
Architecture: arm64
Commit: c8acea2262

.NET SDKs installed:
6.0.428 [/usr/local/share/dotnet/sdk]
9.0.102 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.36 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.36 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
Not set

global.json file:
Not found

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https://aka.ms/dotnet/info

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https://aka.ms/dotnet/download

[captainsafia]

@alinia Excellent bug finding!

I believe the issue here is actually a definition in the ApiDescription type that OpenAPI sources endpoints from. We only capture the relative path associated with an endpoint, not the full request path. I think we might benefit from introducing a Path property to the API description that allows us to capture the full route from branched patterns like this.

I'll mark this down for something to take action on with an API proposal.