From e2061e571d5f0540e45c1a0c7e5a9cbd2d88d2f1 Mon Sep 17 00:00:00 2001
From: Yordis Prieto <yordis.prieto@gmail.com>
Date: Tue, 14 Apr 2026 22:08:59 -0400
Subject: [PATCH 1/2] fix(types): reflect partial failure context construction

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
---
 lib/commanded/event/failure_context.ex | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/commanded/event/failure_context.ex b/lib/commanded/event/failure_context.ex
index a1097070..4e251e2e 100644
--- a/lib/commanded/event/failure_context.ex
+++ b/lib/commanded/event/failure_context.ex
@@ -24,11 +24,11 @@ defmodule Commanded.Event.FailureContext do
   alias Commanded.EventStore.EnrichedMetadata
 
   @type t :: %__MODULE__{
-          application: Commanded.Application.t(),
-          handler_name: String.t(),
+          application: Commanded.Application.app_ref() | nil,
+          handler_name: String.t() | nil,
           handler_state: nil | any(),
-          context: map(),
-          metadata: EnrichedMetadata.t(),
+          context: map() | nil,
+          metadata: EnrichedMetadata.t() | nil,
           stacktrace: Exception.stacktrace() | nil
         }
 

From 56551f213080d1e9f983cac8c74cff32fbae0dea Mon Sep 17 00:00:00 2001
From: Yordis Prieto <yordis.prieto@gmail.com>
Date: Tue, 14 Apr 2026 23:07:20 -0400
Subject: [PATCH 2/2] fix(types): keep failure context strict

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>
---
 lib/commanded/event/failure_context.ex      | 10 ++++---
 test/commanded/event/error_handler_test.exs | 32 +++++++++++++++++----
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/lib/commanded/event/failure_context.ex b/lib/commanded/event/failure_context.ex
index 4e251e2e..7a9292df 100644
--- a/lib/commanded/event/failure_context.ex
+++ b/lib/commanded/event/failure_context.ex
@@ -24,14 +24,16 @@ defmodule Commanded.Event.FailureContext do
   alias Commanded.EventStore.EnrichedMetadata
 
   @type t :: %__MODULE__{
-          application: Commanded.Application.app_ref() | nil,
-          handler_name: String.t() | nil,
+          application: Commanded.Application.app_ref(),
+          handler_name: String.t(),
           handler_state: nil | any(),
-          context: map() | nil,
-          metadata: EnrichedMetadata.t() | nil,
+          context: map(),
+          metadata: EnrichedMetadata.t(),
           stacktrace: Exception.stacktrace() | nil
         }
 
+  @enforce_keys [:application, :handler_name, :context, :metadata]
+
   defstruct [
     :application,
     :handler_name,
diff --git a/test/commanded/event/error_handler_test.exs b/test/commanded/event/error_handler_test.exs
index 128fd4f4..cb1c147c 100644
--- a/test/commanded/event/error_handler_test.exs
+++ b/test/commanded/event/error_handler_test.exs
@@ -9,7 +9,7 @@ defmodule Commanded.Event.ErrorHandlerTest do
   end
 
   test "Stop on error" do
-    context = %FailureContext{}
+    context = failure_context()
     error = {:error, "an error"}
 
     result = ErrorHandler.stop_on_error(error, an_event(), context)
@@ -18,7 +18,7 @@ defmodule Commanded.Event.ErrorHandlerTest do
 
   describe "backoff" do
     test "the first delay is 1 second" do
-      context = %FailureContext{context: %{}}
+      context = failure_context()
 
       {:retry, delay, context} =
         ErrorHandler.backoff(an_error(), an_event(), context, jitter_fn: no_jitter())
@@ -37,7 +37,7 @@ defmodule Commanded.Event.ErrorHandlerTest do
     end
 
     test "backs off exponentially-ish" do
-      failure_context = %FailureContext{context: %{}}
+      failure_context = failure_context()
 
       expectations = [
         {1, 1_000},
@@ -66,7 +66,7 @@ defmodule Commanded.Event.ErrorHandlerTest do
 
     test "maxes out at 1 day" do
       # We should hit the max after 294 failures
-      context = %FailureContext{context: %{failures: 500}}
+      context = failure_context(%{failures: 500})
 
       {:retry, actual_delay, _context} =
         ErrorHandler.backoff(an_error(), an_event(), context, jitter_fn: no_jitter())
@@ -122,5 +122,27 @@ defmodule Commanded.Event.ErrorHandlerTest do
   defp an_event, do: %Event{id: 123}
   defp an_error, do: {:error, "Invalid pizza toppings"}
   defp no_jitter, do: fn -> 0 end
-  defp failure_context, do: %FailureContext{context: %{}}
+
+  defp failure_context(context \\ %{}) do
+    %FailureContext{
+      application: MyApp.CommandedApp,
+      handler_name: "MyApp.FailingEventHandler",
+      handler_state: nil,
+      context: context,
+      metadata: %{
+        event_id: "0f117f39-3b2f-491e-b39d-9325fd1d19d1",
+        event_number: 1,
+        stream_id: "2iO5kHYbIAGW1rrZ7FeHCRMvbT5",
+        stream_version: 1,
+        correlation_id: "e9c3b49e-0ac5-44db-8ddb-83835a7c9437",
+        causation_id: "49d9a83c-8bcd-4fa9-9ccb-3c196717415c",
+        created_at: ~U[2024-06-25 20:55:24.576545Z],
+        application: MyApp.CommandedApp,
+        handler_name: "MyApp.FailingEventHandler",
+        state: nil,
+        metadata: %{}
+      },
+      stacktrace: nil
+    }
+  end
 end