From e784eb015d754e1d0aa74d8fc2b380cdc4907377 Mon Sep 17 00:00:00 2001
From: Adam Stachowicz <adam.stachowicz@fingo.net>
Date: Tue, 26 Nov 2024 16:09:51 +0100
Subject: [PATCH] Display all conflicting actions

---
 .../AspNetCoreOpenApiDocumentGenerator.cs                | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/NSwag.Generation.AspNetCore/AspNetCoreOpenApiDocumentGenerator.cs b/src/NSwag.Generation.AspNetCore/AspNetCoreOpenApiDocumentGenerator.cs
index ceb74a7f7..832480c15 100644
--- a/src/NSwag.Generation.AspNetCore/AspNetCoreOpenApiDocumentGenerator.cs
+++ b/src/NSwag.Generation.AspNetCore/AspNetCoreOpenApiDocumentGenerator.cs
@@ -336,11 +336,12 @@ private List<Tuple<OpenApiOperationDescription, ApiDescription, MethodInfo>> Add
 
                     if (pathItem.ContainsKey(operation.Method))
                     {
-                        var conflictingApiDescription = addedOperations
-                            .First(t => t.Item1.Path == operation.Path && t.Item1.Method == operation.Method)
-                            .Item2;
+                        var conflictingApiDescriptions = operations
+                            .Where(t => t.Item1.Path == operation.Path && t.Item1.Method == operation.Method)
+                            .Select(t => t.Item2)
+                            .ToList();
 
-                        throw new InvalidOperationException($"The method '{operation.Method}' on path '{path}' is registered multiple times for actions {conflictingApiDescription.ActionDescriptor.DisplayName} and {apiDescription.ActionDescriptor.DisplayName}.");
+                        throw new InvalidOperationException($"The method '{operation.Method}' on path '{path}' is registered multiple times for actions {string.Join(", ", conflictingApiDescriptions.Select(apiDesc => apiDesc.ActionDescriptor.DisplayName))}.");
                     }
 
                     pathItem[operation.Method] = operation.Operation;