Fix duplicate attribute when the Body redeclares an Envelope namespace prefix #1196

src/SoapCore.Tests/RawRequestSoap12Tests.cs

@@ -46,6 +46,56 @@ public void Soap12PingWithActionInHeader()
 			}
 		}
 
+		[TestMethod]
+		public void Soap12PingWithNamespaceDeclarationsRepeatedOnBody()
+		{
+			var body = @"<?xml version=""1.0"" encoding=""utf-8""?>
+<soap12:Envelope xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" xmlns:xsd=""http://www.w3.org/2001/XMLSchema"" xmlns:soap12=""http://www.w3.org/2003/05/soap-envelope"">
+  <soap12:Body xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" xmlns:xsd=""http://www.w3.org/2001/XMLSchema"" xmlns:soap12=""http://www.w3.org/2003/05/soap-envelope"">
+    <Ping xmlns=""http://tempuri.org/"">
+      <s>abc</s>
+    </Ping>
+  </soap12:Body>
+</soap12:Envelope>
+";
+			var bodyBytes = Encoding.UTF8.GetBytes(body);
+			using (var host = CreateTestHost())
+			using (var client = host.CreateClient())
+			using (var content = new StringContent(body, Encoding.UTF8, "application/soap+xml"))
+			{
+				content.Headers.ContentType.Parameters.Add(new System.Net.Http.Headers.NameValueHeaderValue("action", "\"http://tempuri.org/ITestService/Ping\""));
+				using (var res = host.CreateRequest("/Service.svc").And(msg => msg.Content = content).PostAsync().Result)
+				{
+					res.EnsureSuccessStatusCode();
+				}
+			}
+		}
+
+		[TestMethod]
+		public void Soap12PingWithPrefixShadowedOnBody()
+		{
+			var body = @"<?xml version=""1.0"" encoding=""utf-8""?>
+<soap12:Envelope xmlns:soap12=""http://www.w3.org/2003/05/soap-envelope"" xmlns:tns=""http://example.org/not-tempuri"">
+  <soap12:Body xmlns:tns=""http://tempuri.org/"">
+    <tns:Ping>
+      <tns:s>abc</tns:s>
+    </tns:Ping>
+  </soap12:Body>
+</soap12:Envelope>
+";
+			var bodyBytes = Encoding.UTF8.GetBytes(body);
+			using (var host = CreateTestHost())
+			using (var client = host.CreateClient())
+			using (var content = new StringContent(body, Encoding.UTF8, "application/soap+xml"))
+			{
+				content.Headers.ContentType.Parameters.Add(new System.Net.Http.Headers.NameValueHeaderValue("action", "\"http://tempuri.org/ITestService/Ping\""));
+				using (var res = host.CreateRequest("/Service.svc").And(msg => msg.Content = content).PostAsync().Result)
+				{
+					res.EnsureSuccessStatusCode();
+				}
+			}
+		}
+
 		[TestMethod]
 		public void Soap12PingWithActionInEnvelopeHeader()
 		{
@@ -253,8 +303,8 @@ public async Task Soap12DetailedFault()
 					ExceptionProperty = "Detail message"
 				});
 			}
-		}
-
+		}
+
 		[TestMethod]
 		public async Task Soap12InvalidSchema()
 		{

src/SoapCore/ParsedMessage.cs

@@ -188,9 +188,12 @@ private static (XDocument, bool isEmpty) ExtractSoapBody(XDocument envelope, Mes
 				return (new XDocument(), true);
 			}
 
-			var rootAttributes = root.Attributes();
+			// The envelope attributes are carried onto the body so that it keeps its namespace bindings once it is
+			// detached. An attribute the body already declares has to win: XAttribute does not override equality, so
+			// Union compares by reference and a declaration present on both elements would be added twice and throw.
 			var bodyAttributes = bodyNode.Attributes();
-			var allAttributes = bodyAttributes.Union(rootAttributes);
+			var rootAttributes = root.Attributes().Where(attribute => bodyNode.Attribute(attribute.Name) == null);
+			var allAttributes = bodyAttributes.Concat(rootAttributes).ToList();
 			bodyNode.ReplaceAttributes(allAttributes);
 
 			//return new XDocument(bodyNode.Elements().FirstOrDefault());