Fix build warning in samples

EraYaN · EraYaN · commit e65c93919101 · 2025-10-27T09:28:51.000+01:00
diff --git a/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/ClientUtils.mustache b/modules/openapi-generator/src/main/resources/csharp/libraries/generichost/ClientUtils.mustache
@@ -324,7 +324,12 @@ using System.Net.Http.Headers;
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                {{#net80OrLater}}
+                    return [];
+                {{/net80OrLater}}
+                {{^net80OrLater}}
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
+                {{/net80OrLater}}
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                 {{#net80OrLater}}
diff --git a/samples/client/petstore/csharp/generichost/latest/ComposedEnum/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/latest/ComposedEnum/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -239,7 +239,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/latest/HelloWorld/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/latest/HelloWorld/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/latest/InlineEnumAnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/latest/InlineEnumAnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -235,7 +235,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/latest/OneOfList/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/latest/OneOfList/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/latest/Tags/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/latest/Tags/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -259,7 +259,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net4.7/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -229,7 +229,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -344,7 +344,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -348,7 +348,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.7/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.7/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -229,7 +229,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -229,7 +229,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -344,7 +344,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -348,7 +348,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net4.8/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net4.8/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -229,7 +229,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };
diff --git a/samples/client/petstore/csharp/generichost/net8/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -343,7 +343,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -349,7 +349,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -347,7 +347,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -349,7 +349,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net8/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net8/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/AllOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/AnyOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/AnyOfNoCompare/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -343,7 +343,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -349,7 +349,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/OneOf/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -248,7 +248,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -347,7 +347,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -349,7 +349,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/net9/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/net9/UseDateTimeForDate/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return [];
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return [MediaTypeWithQualityHeaderValue.Parse("application/json")];
diff --git a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Client/ClientUtils.cs
@@ -348,7 +348,7 @@ public static string SelectHeaderAccept(string[] accepts)
         public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)
         {
             if (accepts.Length == 0)
-                return null;
+                    return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();
 
             if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))
                     return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };

Original file line number	Diff line number	Diff line change
`@@ -239,7 +239,7 @@ public static byte[] ReadAsBytes(Stream inputStream)`
`239`	`239`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`240`	`240`	`{`
`241`	`241`	`if (accepts.Length == 0)`
`242`		`- return null;`
	`242`	`+ return [];`
`243`	`243`
`244`	`244`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`245`	`245`	`return [MediaTypeWithQualityHeaderValue.Parse("application/json")];`
Original file line number	Diff line number	Diff line change
`@@ -233,7 +233,7 @@ public static byte[] ReadAsBytes(Stream inputStream)`
`233`	`233`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`234`	`234`	`{`
`235`	`235`	`if (accepts.Length == 0)`
`236`		`- return null;`
	`236`	`+ return [];`
`237`	`237`
`238`	`238`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`239`	`239`	`return [MediaTypeWithQualityHeaderValue.Parse("application/json")];`
Original file line number	Diff line number	Diff line change
`@@ -235,7 +235,7 @@ public static byte[] ReadAsBytes(Stream inputStream)`
`235`	`235`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`236`	`236`	`{`
`237`	`237`	`if (accepts.Length == 0)`
`238`		`- return null;`
	`238`	`+ return [];`
`239`	`239`
`240`	`240`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`241`	`241`	`return [MediaTypeWithQualityHeaderValue.Parse("application/json")];`
Original file line number	Diff line number	Diff line change
`@@ -259,7 +259,7 @@ public static byte[] ReadAsBytes(Stream inputStream)`
`259`	`259`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`260`	`260`	`{`
`261`	`261`	`if (accepts.Length == 0)`
`262`		`- return null;`
	`262`	`+ return [];`
`263`	`263`
`264`	`264`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`265`	`265`	`return [MediaTypeWithQualityHeaderValue.Parse("application/json")];`
Original file line number	Diff line number	Diff line change
`@@ -244,7 +244,7 @@ public static string SelectHeaderAccept(string[] accepts)`
`244`	`244`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`245`	`245`	`{`
`246`	`246`	`if (accepts.Length == 0)`
`247`		`- return null;`
	`247`	`+ return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();`
`248`	`248`
`249`	`249`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`250`	`250`	`return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };`
Original file line number	Diff line number	Diff line change
`@@ -229,7 +229,7 @@ public static string SelectHeaderAccept(string[] accepts)`
`229`	`229`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`230`	`230`	`{`
`231`	`231`	`if (accepts.Length == 0)`
`232`		`- return null;`
	`232`	`+ return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();`
`233`	`233`
`234`	`234`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`235`	`235`	`return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };`
Original file line number	Diff line number	Diff line change
`@@ -344,7 +344,7 @@ public static string SelectHeaderAccept(string[] accepts)`
`344`	`344`	`public static IEnumerable<MediaTypeWithQualityHeaderValue> SelectHeaderAcceptArray(string[] accepts)`
`345`	`345`	`{`
`346`	`346`	`if (accepts.Length == 0)`
`347`		`- return null;`
	`347`	`+ return Enumerable.Empty<MediaTypeWithQualityHeaderValue>();`
`348`	`348`
`349`	`349`	`if (accepts.Contains("application/json", StringComparer.OrdinalIgnoreCase))`
`350`	`350`	`return new [] { MediaTypeWithQualityHeaderValue.Parse("application/json") };`