fix!: Send Service Bus events as single objects instead of arrays

Service Bus delivery now always serializes events as single JSON objects
without array wrapping, matching Azure Event Grid's actual behavior.
Previously events were wrapped in a single-element array which forced
consumers to add unnecessary array-handling logic.

Removes the singleEventDelivery configuration option in favour of always
using the correct Azure behavior.

Also updates the commit-msg hook to support the ! breaking change
indicator per the Conventional Commits spec.

BREAKING CHANGE: Service Bus message bodies are now single JSON objects
instead of single-element arrays. Consumers that parse the array format
will need to be updated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: pm7y

.githooks/commit-msg

@@ -15,16 +15,19 @@ if echo "$commit_msg" | grep -qE "^Merge "; then
     exit 0
 fi
 
-# Conventional commit pattern: type(optional scope): description
+# Conventional commit pattern: type(optional scope)(optional !): description
 # Types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert, deps
-pattern="^(feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert|deps)(\(.+\))?: .+"
+# The optional ! before the colon indicates a breaking change.
+pattern="^(feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert|deps)(\(.+\))?!?: .+"
 
 if ! echo "$commit_msg" | head -1 | grep -qE "$pattern"; then
     echo ""
     echo "ERROR: Commit message does not follow Conventional Commits format."
     echo ""
     echo "Expected format: <type>: <description>"
     echo "                 <type>(<scope>): <description>"
+    echo "                 <type>!: <description>"
+    echo "                 <type>(<scope>)!: <description>"
     echo ""
     echo "Valid types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert, deps"
     echo ""
@@ -33,8 +36,11 @@ if ! echo "$commit_msg" | head -1 | grep -qE "$pattern"; then
     echo "  fix: resolve validation error"
     echo "  docs: update README"
     echo "  chore(deps): update dependencies"
+    echo "  fix!: change Service Bus message format"
+    echo "  feat(api)!: remove deprecated endpoint"
     echo ""
     echo "Note: There must be a space after the colon."
+    echo "      Use ! before the colon to indicate a breaking change."
     echo ""
     echo "Your commit message was:"
     echo "  $(head -1 "$commit_msg_file")"

src/AzureEventGridSimulator.Tests/UnitTests/Subscribers/Delivery/ServiceBusEventDeliveryServiceTests.cs

@@ -184,7 +184,7 @@ EventSchema schema
     }
 
     [Fact]
-    public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJson()
+    public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJsonArray()
     {
         var formatter = _formatterFactory.GetFormatter(EventSchema.EventGridSchema);
         var evt = CreateTestEvent();
@@ -193,10 +193,12 @@ public void GivenEventGridFormatter_WhenSerializing_ThenReturnsJson()
 
         json.ShouldNotBeNullOrEmpty();
         json.ShouldContain("test-event-id");
+        json.TrimStart().ShouldStartWith("[");
+        json.TrimEnd().ShouldEndWith("]");
     }
 
     [Fact]
-    public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJson()
+    public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJsonArray()
     {
         var formatter = _formatterFactory.GetFormatter(EventSchema.CloudEventV1_0);
         var evt = CreateTestEvent();
@@ -205,6 +207,8 @@ public void GivenCloudEventFormatter_WhenSerializing_ThenReturnsJson()
 
         json.ShouldNotBeNullOrEmpty();
         json.ShouldContain("test-event-id");
+        json.TrimStart().ShouldStartWith("[");
+        json.TrimEnd().ShouldEndWith("]");
     }
 
     [Fact]
@@ -278,42 +282,4 @@ public void GivenEventGridFormatter_WhenSerializingSingle_ThenReturnsJsonWithout
         json.TrimStart().ShouldStartWith("{");
         json.TrimEnd().ShouldEndWith("}");
     }
-
-    [Fact]
-    public void GivenSubscriptionWithSingleEventDelivery_WhenConfigured_ThenPropertyIsSet()
-    {
-        var subscription = new ServiceBusSubscriberSettings
-        {
-            Name = "TestSubscriber",
-            ConnectionString =
-                "Endpoint=sb://my-namespace.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=abc123",
-            Queue = "my-queue",
-            SingleEventDelivery = true,
-        };
-
-        subscription.SingleEventDelivery.ShouldBe(true);
-    }
-
-    [Fact]
-    public void GivenSubscriptionWithoutSingleEventDelivery_WhenConfigured_ThenPropertyIsNull()
-    {
-        var subscription = CreateValidQueueSettings();
-
-        subscription.SingleEventDelivery.ShouldBeNull();
-    }
-
-    [Fact]
-    public void GivenSubscriptionWithSingleEventDeliveryFalse_WhenConfigured_ThenPropertyIsFalse()
-    {
-        var subscription = new ServiceBusSubscriberSettings
-        {
-            Name = "TestSubscriber",
-            ConnectionString =
-                "Endpoint=sb://my-namespace.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=abc123",
-            Queue = "my-queue",
-            SingleEventDelivery = false,
-        };
-
-        subscription.SingleEventDelivery.ShouldBe(false);
-    }
 }

src/AzureEventGridSimulator/Domain/Services/Delivery/ServiceBusEventDeliveryService.cs

@@ -58,11 +58,8 @@ CancellationToken cancellationToken
                 subscription.DeliverySchema ?? delivery.Topic.OutputSchema ?? delivery.InputSchema;
             var formatter = formatterFactory.GetFormatter(deliverySchema);
 
-            // Serialize the event (use single event format if configured)
-            var json =
-                subscription.SingleEventDelivery == true
-                    ? formatter.SerializeSingle(delivery.Event)
-                    : formatter.Serialize(delivery.Event);
+            // Serialize as a single event (matches Azure Event Grid to Service Bus behavior)
+            var json = formatter.SerializeSingle(delivery.Event);
 
             // Get or create the sender
             var sender = GetOrCreateSender(subscription);
@@ -174,11 +171,8 @@ EventSchema inputSchema
             var deliverySchema = subscription.DeliverySchema ?? topic.OutputSchema ?? inputSchema;
             var formatter = formatterFactory.GetFormatter(deliverySchema);
 
-            // Serialize the event (use single event format if configured)
-            var json =
-                subscription.SingleEventDelivery == true
-                    ? formatter.SerializeSingle(evt)
-                    : formatter.Serialize(evt);
+            // Serialize as a single event (matches Azure Event Grid to Service Bus behavior)
+            var json = formatter.SerializeSingle(evt);
 
             // Get or create the sender
             var sender = GetOrCreateSender(subscription);

src/AzureEventGridSimulator/Infrastructure/Settings/Subscribers/ServiceBusSubscriberSettings.cs

@@ -130,14 +130,6 @@ public string? EffectiveConnectionString
     [JsonConverter(typeof(JsonStringEnumConverter))]
     public EventSchema? DeliverySchema { get; init; }
 
-    /// <summary>
-    ///     Gets or sets whether to send events as single objects without array wrapper.
-    ///     When true, events are sent as individual objects (Azure behavior for Service Bus).
-    ///     When false or null, events are sent in an array with a single event (default for backward compatibility).
-    /// </summary>
-    [JsonPropertyName("singleEventDelivery")]
-    public bool? SingleEventDelivery { get; init; }
-
     /// <summary>
     ///     Gets or sets the retry policy for this subscriber.
     ///     If null, default Azure Event Grid retry behavior is used (enabled with 30 attempts, 24h TTL).