gRPC SwaggerGen does not handle conflicting paths

src/Grpc/JsonTranscoding/src/Microsoft.AspNetCore.Grpc.Swagger/Internal/GrpcJsonTranscodingDescriptionProvider.cs

@@ -178,9 +178,43 @@ private static string ResolvePath(HttpRoutePattern httpRoutePattern, Dictionary<
             var routeParameter = routeParameters.SingleOrDefault(kvp => kvp.Value.RouteVariable.StartSegment == i).Value;
             if (routeParameter != null)
             {
-                sb.Append('{');
-                sb.Append(routeParameter.JsonPath);
-                sb.Append('}');
+                // For variables that span multiple segments (e.g., {name=widgets/*}),
+                // include the literal segments to make unique OpenAPI paths.
+                var startSegment = routeParameter.RouteVariable.StartSegment;
+                var endSegment = routeParameter.RouteVariable.EndSegment;
+
+                if (endSegment - startSegment > 1)
+                {
+                    // Multi-segment variable - include literal segments for uniqueness
+                    for (var j = startSegment; j < endSegment; j++)
+                    {
+                        if (j > startSegment)
+                        {
+                            sb.Append('/');
+                        }
+
+                        var segment = httpRoutePattern.Segments[j];
+                        if (segment == "*" || segment == "**")
+                        {
+                            // Replace wildcard with parameter
+                            sb.Append('{');
+                            sb.Append(routeParameter.JsonPath);
+                            sb.Append('}');
+                        }
+                        else
+                        {
+                            // Include literal segment as-is
+                            sb.Append(segment);
+                        }
+                    }
+                }
+                else
+                {
+                    // Single-segment variable
+                    sb.Append('{');
+                    sb.Append(routeParameter.JsonPath);
+                    sb.Append('}');
+                }
 
                 // Skip segments if variable is multiple segment.
                 i = routeParameter.RouteVariable.EndSegment - 1;

src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.Swagger.Tests/Binding/ResourcePathTests.cs

@@ -0,0 +1,53 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Grpc.Swagger.Tests.Infrastructure;
+using Microsoft.AspNetCore.Grpc.Swagger.Tests.Services;
+using Microsoft.OpenApi.Models;
+using Xunit.Abstractions;
+
+namespace Microsoft.AspNetCore.Grpc.Swagger.Tests.Binding;
+
+public class ResourcePathTests
+{
+    private readonly ITestOutputHelper _testOutputHelper;
+
+    public ResourcePathTests(ITestOutputHelper testOutputHelper)
+    {
+        _testOutputHelper = testOutputHelper;
+    }
+
+    [Fact]
+    public void ConflictingPaths_DifferentLiteralSegments_GenerateUniquePaths()
+    {
+        // Arrange & Act
+        var swagger = OpenApiTestHelpers.GetOpenApiDocument<ResourceService>(_testOutputHelper);
+
+        // Assert - Should have 3 distinct paths
+        Assert.Equal(3, swagger.Paths.Count);
+
+        // Path 1: /v1/widgets/{name}
+        Assert.True(swagger.Paths.ContainsKey("/v1/widgets/{name}"));
+        var widgetPath = swagger.Paths["/v1/widgets/{name}"];
+        Assert.True(widgetPath.Operations.TryGetValue(OperationType.Get, out var widgetOperation));
+        Assert.Single(widgetOperation.Parameters);
+        Assert.Equal(ParameterLocation.Path, widgetOperation.Parameters[0].In);
+        Assert.Equal("name", widgetOperation.Parameters[0].Name);
+
+        // Path 2: /v1/things/{name}
+        Assert.True(swagger.Paths.ContainsKey("/v1/things/{name}"));
+        var thingPath = swagger.Paths["/v1/things/{name}"];
+        Assert.True(thingPath.Operations.TryGetValue(OperationType.Get, out var thingOperation));
+        Assert.Single(thingOperation.Parameters);
+        Assert.Equal(ParameterLocation.Path, thingOperation.Parameters[0].In);
+        Assert.Equal("name", thingOperation.Parameters[0].Name);
+
+        // Path 3: /v1/gadgets/{name}/items/{name} (nested path)
+        Assert.True(swagger.Paths.ContainsKey("/v1/gadgets/{name}/items/{name}"));
+        var gadgetPath = swagger.Paths["/v1/gadgets/{name}/items/{name}"];
+        Assert.True(gadgetPath.Operations.TryGetValue(OperationType.Get, out var gadgetOperation));
+        Assert.Single(gadgetOperation.Parameters);
+        Assert.Equal(ParameterLocation.Path, gadgetOperation.Parameters[0].In);
+        Assert.Equal("name", gadgetOperation.Parameters[0].Name);
+    }
+}

src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.Swagger.Tests/Microsoft.AspNetCore.Grpc.Swagger.Tests.csproj

@@ -13,6 +13,7 @@
     <Protobuf Include="Proto\xmldoc.proto" GrpcServices="Both" />
     <Protobuf Include="Proto\greeter.proto" GrpcServices="Both" />
     <Protobuf Include="Proto\messages.proto" GrpcServices="Both" />
+    <Protobuf Include="Proto\resources.proto" GrpcServices="Both" />
 
     <Reference Include="Microsoft.AspNetCore.Grpc.Swagger" />
     <Reference Include="Grpc.Tools" PrivateAssets="All" />

src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.Swagger.Tests/Proto/resources.proto

@@ -0,0 +1,59 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+syntax = "proto3";
+
+import "google/api/annotations.proto";
+
+package resources;
+
+// Service for testing Google AIP-131 style resource patterns
+service ResourceService {
+  // Get a widget by name
+  rpc GetWidget (WidgetRequest) returns (WidgetResponse) {
+    option (google.api.http) = {
+      get: "/v1/{name=widgets/*}"
+    };
+  }
+
+  // Get a thing by name
+  rpc GetThing (ThingRequest) returns (ThingResponse) {
+    option (google.api.http) = {
+      get: "/v1/{name=things/*}"
+    };
+  }
+
+  // Get a gadget with nested path
+  rpc GetGadget (GadgetRequest) returns (GadgetResponse) {
+    option (google.api.http) = {
+      get: "/v1/{name=gadgets/*/items/*}"
+    };
+  }
+}
+
+message WidgetRequest {
+  string name = 1;
+}
+
+message WidgetResponse {
+  string id = 1;
+  string name = 2;
+}
+
+message ThingRequest {
+  string name = 1;
+}
+
+message ThingResponse {
+  string id = 1;
+  string name = 2;
+}
+
+message GadgetRequest {
+  string name = 1;
+}
+
+message GadgetResponse {
+  string id = 1;
+  string name = 2;
+}

src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.Swagger.Tests/Services/ResourceService.cs

@@ -0,0 +1,8 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Grpc.Swagger.Tests.Services;
+
+public class ResourceService : Resources.ResourceServiceBase
+{
+}