Extension value nullability (Azure#19287)

* Make extension attribute value not nullable

* Export API

* fix comment

Author: JoshLove-msft

sdk/core/Azure.Core/api/Azure.Core.net461.cs

@@ -581,7 +581,7 @@ public CloudEvent(string source, string type, object? jsonSerializableData, Syst
         public System.BinaryData? Data { get { throw null; } set { } }
         public string? DataContentType { get { throw null; } set { } }
         public string? DataSchema { get { throw null; } set { } }
-        public System.Collections.Generic.IDictionary<string, object?> ExtensionAttributes { get { throw null; } }
+        public System.Collections.Generic.IDictionary<string, object> ExtensionAttributes { get { throw null; } }
         public string Id { get { throw null; } set { } }
         public string Source { get { throw null; } set { } }
         public string? Subject { get { throw null; } set { } }

sdk/core/Azure.Core/api/Azure.Core.net5.0.cs

@@ -581,7 +581,7 @@ public CloudEvent(string source, string type, object? jsonSerializableData, Syst
         public System.BinaryData? Data { get { throw null; } set { } }
         public string? DataContentType { get { throw null; } set { } }
         public string? DataSchema { get { throw null; } set { } }
-        public System.Collections.Generic.IDictionary<string, object?> ExtensionAttributes { get { throw null; } }
+        public System.Collections.Generic.IDictionary<string, object> ExtensionAttributes { get { throw null; } }
         public string Id { get { throw null; } set { } }
         public string Source { get { throw null; } set { } }
         public string? Subject { get { throw null; } set { } }

sdk/core/Azure.Core/api/Azure.Core.netstandard2.0.cs

@@ -581,7 +581,7 @@ public CloudEvent(string source, string type, object? jsonSerializableData, Syst
         public System.BinaryData? Data { get { throw null; } set { } }
         public string? DataContentType { get { throw null; } set { } }
         public string? DataSchema { get { throw null; } set { } }
-        public System.Collections.Generic.IDictionary<string, object?> ExtensionAttributes { get { throw null; } }
+        public System.Collections.Generic.IDictionary<string, object> ExtensionAttributes { get { throw null; } }
         public string Id { get { throw null; } set { } }
         public string Source { get { throw null; } set { } }
         public string? Subject { get { throw null; } set { } }

sdk/core/Azure.Core/src/Messaging/CloudEvent.cs

@@ -141,7 +141,7 @@ public string Type
         /// <summary>
         /// Gets extension attributes that can be additionally added to the CloudEvent envelope.
         /// </summary>
-        public IDictionary<string, object?> ExtensionAttributes { get; } = new CloudEventExtensionAttributes<string, object?>();
+        public IDictionary<string, object> ExtensionAttributes { get; } = new CloudEventExtensionAttributes<string, object>();
 
         /// <summary>
         /// Given JSON-encoded events, parses the event envelope and returns an array of CloudEvents.

sdk/core/Azure.Core/src/Messaging/CloudEventConverter.cs

@@ -97,13 +97,13 @@ internal static CloudEvent DeserializeCloudEvent(JsonElement element, bool skipV
                 {
                     if (!skipValidation)
                     {
-                        cloudEvent.ExtensionAttributes.Add(property.Name, GetObject(property.Value));
+                        cloudEvent.ExtensionAttributes.Add(property.Name, GetObject(property.Value)!);
                     }
                     else
                     {
                         // This aspect of skipValidation would not be supported for converters that live in a different
                         // package since CloudEventExtensionAttributes is internal.
-                        ((CloudEventExtensionAttributes<string, object?>)cloudEvent.ExtensionAttributes).AddWithoutValidation(property.Name, GetObject(property.Value));
+                        ((CloudEventExtensionAttributes<string, object>)cloudEvent.ExtensionAttributes).AddWithoutValidation(property.Name, GetObject(property.Value)!);
                     }
                 }
             }
@@ -213,7 +213,7 @@ public override void Write(Utf8JsonWriter writer, CloudEvent value, JsonSerializ
                 writer.WritePropertyName(CloudEventConstants.Subject);
                 writer.WriteStringValue(value.Subject);
             }
-            foreach (KeyValuePair<string, object?> item in value.ExtensionAttributes)
+            foreach (KeyValuePair<string, object> item in value.ExtensionAttributes)
             {
                 writer.WritePropertyName(item.Key);
                 WriteObjectValue(writer, item.Value);

sdk/core/Azure.Core/tests/CloudEventTests.cs

@@ -926,6 +926,29 @@ public void CanParseInvalidAttributes(bool skipValidation)
                 Assert.AreEqual(5, ((IDictionary<string, object>)evt.ExtensionAttributes["dict"])["key2"]);
             }
         }
+
+        [Test]
+        [TestCase(true)]
+        [TestCase(false)]
+        public void CanParseNullAttributeValue(bool skipValidation)
+        {
+            // null extension attribute values can still be deserialized.
+            var json = new BinaryData("{\"subject\": \"Subject-0\", \"source\":\"source\", \"specversion\":\"1.0\", \"id\": \"id\", \"type\": \"type\", \"key\":null }");
+
+            if (!skipValidation)
+            {
+                Assert.That(
+                    () => CloudEvent.ParseMany(json),
+                    Throws.InstanceOf<ArgumentException>());
+            }
+            else
+            {
+                var evt = CloudEvent.ParseMany(json, true)[0];
+                Assert.AreEqual("Subject-0", evt.Subject);
+                Assert.AreEqual("type", evt.Type);
+                Assert.IsNull(evt.ExtensionAttributes["key"]);
+            }
+        }
     }
 
 #pragma warning disable SA1402 // File may only contain a single type