Thread ProcessStateChange through ProcessEngine.Start to fulfill nullability contract.

Author: bjorntore

AGENTS.md

@@ -115,6 +115,7 @@ The libraries integrate with:
 - Use internal accessibility on types by default
 - Use sealed for classes unless we consider inheritance a valid use-case
 - Use Nullable Reference Types
+- Don't use null forgiveness operator without justification
 - Remember to dispose `IDisposable`/`IAsyncDisposable` instances
 - We want to minimize external dependencies
 - For HTTP APIs we should have `...Request` and `...Response` DTOs (see `LookupPersonRequest.cs` and the corresponding response as an example)

src/Altinn.App.Api/Controllers/InstancesController.cs

@@ -381,14 +381,17 @@ await _instanceClient.DeleteInstance(
                 Guid.Parse(instance.Id.Split("/")[1])
             );
 
-            _logger.LogInformation("Events sent to process engine: {Events}", change?.Events);
+            if (change is null)
+                throw new InvalidOperationException("ProcessStateChange was not set by GenerateProcessStartEvents");
+
             ProcessChangeResult startProcessResult = await _processEngine.Start(
                 instance,
-                change?.Events,
+                change,
                 User,
                 language: language,
                 ct: HttpContext.RequestAborted
             );
+
             if (!startProcessResult.Success)
                 return Conflict(startProcessResult.ErrorMessage);
 
@@ -607,16 +610,22 @@ public async Task<ActionResult<InstanceResponse>> PostSimplified(
             }
 
             instance = await _instanceClient.GetInstance(instance);
+
+            if (!processResult.Success)
+                return Conflict(processResult.ErrorMessage);
+
             var startProcessResult = await _processEngine.Start(
                 instance,
-                processResult.ProcessStateChange?.Events,
+                processResult.ProcessStateChange,
                 User,
                 prefill: instansiationInstance.Prefill,
                 language: language,
                 ct: HttpContext.RequestAborted
             );
+
             if (!startProcessResult.Success)
                 return Conflict(startProcessResult.ErrorMessage);
+
             instance = startProcessResult.MutatedInstance;
         }
         catch (Exception exception)
@@ -739,15 +748,20 @@ public async Task<ActionResult> CopyInstance(
 
         targetInstance = await _instanceClient.GetInstance(targetInstance);
 
+        if (!startResult.Success)
+            return Conflict(startResult.ErrorMessage);
+
         var startProcessResult = await _processEngine.Start(
             targetInstance,
-            startResult.ProcessStateChange?.Events,
+            startResult.ProcessStateChange,
             User,
             language: language,
             ct: HttpContext.RequestAborted
         );
+
         if (!startProcessResult.Success)
             return Conflict(startProcessResult.ErrorMessage);
+
         targetInstance = startProcessResult.MutatedInstance;
 
         await RegisterEvent("app.instance.created", targetInstance);

src/Altinn.App.Api/Controllers/ProcessController.cs

@@ -149,7 +149,7 @@ public async Task<ActionResult<AppProcessState>> StartProcess(
 
             var startProcessResult = await _processEngine.Start(
                 instance,
-                result.ProcessStateChange?.Events,
+                result.ProcessStateChange,
                 User,
                 ct: HttpContext.RequestAborted
             );

src/Altinn.App.Core/Internal/Process/Interfaces/IProcessEngine.cs

@@ -39,11 +39,11 @@ Task<Instance> HandleEventsAndUpdateStorage(
 
     /// <summary>
     /// Dispatches process start events to storage and auto-runs any initial service tasks.
-    /// Call after instance creation and data storage, with the events from <see cref="GenerateProcessStartEvents"/>.
+    /// Call after instance creation and data storage, with the result from <see cref="GenerateProcessStartEvents"/>.
     /// </summary>
     Task<ProcessChangeResult> Start(
         Instance instance,
-        List<InstanceEvent>? events,
+        ProcessStateChange processStateChange,
         ClaimsPrincipal user,
         Dictionary<string, string>? prefill = null,
         string? language = null,

src/Altinn.App.Core/Internal/Process/ProcessEngine.cs

@@ -153,7 +153,7 @@ out ProcessError? startEventError
     /// <inheritdoc/>
     public async Task<ProcessChangeResult> Start(
         Instance instance,
-        List<InstanceEvent>? events,
+        ProcessStateChange processStateChange,
         ClaimsPrincipal user,
         Dictionary<string, string>? prefill = null,
         string? language = null,
@@ -163,10 +163,10 @@ public async Task<ProcessChangeResult> Start(
         // HandleEvents mutates instance in-place; we discard the DispatchToStorage
         // return (same as callers did before this method existed).
         bool isServiceTask = IsServiceTask(instance);
-        await HandleEventsAndUpdateStorage(instance, isServiceTask ? null : prefill, events);
+        await HandleEventsAndUpdateStorage(instance, isServiceTask ? null : prefill, processStateChange.Events);
 
         if (!isServiceTask)
-            return new ProcessChangeResult(instance) { Success = true };
+            return new ProcessChangeResult(instance) { Success = true, ProcessStateChange = processStateChange };
 
         // Auto-run through initial service tasks, forwarding prefill to the first user task
         return await Next(

test/Altinn.App.Api.Tests/Controllers/InstancesController_CopyInstanceTests.cs

@@ -379,14 +379,14 @@ public async Task CopyInstance_EverythingIsFine_ReturnsRedirect()
             .Setup(p => p.GenerateProcessStartEvents(It.IsAny<ProcessStartRequest>()))
             .ReturnsAsync(() =>
             {
-                return new ProcessChangeResult() { Success = true };
+                return new ProcessChangeResult() { Success = true, ProcessStateChange = new() };
             });
         fixture
             .Mock<IProcessEngine>()
             .Setup(p =>
                 p.Start(
                     It.IsAny<Instance>(),
-                    It.IsAny<List<InstanceEvent>>(),
+                    It.IsAny<ProcessStateChange>(),
                     It.IsAny<System.Security.Claims.ClaimsPrincipal>(),
                     It.IsAny<Dictionary<string, string>>(),
                     It.IsAny<string>(),
@@ -396,7 +396,7 @@ public async Task CopyInstance_EverythingIsFine_ReturnsRedirect()
             .ReturnsAsync(
                 (
                     Instance inst,
-                    List<InstanceEvent>? _,
+                    ProcessStateChange _,
                     System.Security.Claims.ClaimsPrincipal _,
                     Dictionary<string, string>? _,
                     string? _,
@@ -513,13 +513,13 @@ public async Task CopyInstance_WithBinaryData_CopiesBothFormAndBinaryData()
         fixture
             .Mock<IProcessEngine>()
             .Setup(p => p.GenerateProcessStartEvents(It.IsAny<ProcessStartRequest>()))
-            .ReturnsAsync(() => new ProcessChangeResult() { Success = true });
+            .ReturnsAsync(() => new ProcessChangeResult() { Success = true, ProcessStateChange = new() });
         fixture
             .Mock<IProcessEngine>()
             .Setup(p =>
                 p.Start(
                     It.IsAny<Instance>(),
-                    It.IsAny<List<InstanceEvent>>(),
+                    It.IsAny<ProcessStateChange>(),
                     It.IsAny<System.Security.Claims.ClaimsPrincipal>(),
                     It.IsAny<Dictionary<string, string>>(),
                     It.IsAny<string>(),
@@ -529,7 +529,7 @@ public async Task CopyInstance_WithBinaryData_CopiesBothFormAndBinaryData()
             .ReturnsAsync(
                 (
                     Instance inst,
-                    List<InstanceEvent>? _,
+                    ProcessStateChange _,
                     System.Security.Claims.ClaimsPrincipal _,
                     Dictionary<string, string>? _,
                     string? _,
@@ -725,13 +725,13 @@ public async Task CopyInstance_WithExcludedBinaryDataType_SkipsExcludedType()
         fixture
             .Mock<IProcessEngine>()
             .Setup(p => p.GenerateProcessStartEvents(It.IsAny<ProcessStartRequest>()))
-            .ReturnsAsync(() => new ProcessChangeResult() { Success = true });
+            .ReturnsAsync(() => new ProcessChangeResult() { Success = true, ProcessStateChange = new() });
         fixture
             .Mock<IProcessEngine>()
             .Setup(p =>
                 p.Start(
                     It.IsAny<Instance>(),
-                    It.IsAny<List<InstanceEvent>>(),
+                    It.IsAny<ProcessStateChange>(),
                     It.IsAny<System.Security.Claims.ClaimsPrincipal>(),
                     It.IsAny<Dictionary<string, string>>(),
                     It.IsAny<string>(),
@@ -741,7 +741,7 @@ public async Task CopyInstance_WithExcludedBinaryDataType_SkipsExcludedType()
             .ReturnsAsync(
                 (
                     Instance inst,
-                    List<InstanceEvent>? _,
+                    ProcessStateChange _,
                     System.Security.Claims.ClaimsPrincipal _,
                     Dictionary<string, string>? _,
                     string? _,
@@ -936,13 +936,13 @@ public async Task CopyInstance_IncludeAttachmentsIsTrue_CopiesBinaryData()
         fixture
             .Mock<IProcessEngine>()
             .Setup(p => p.GenerateProcessStartEvents(It.IsAny<ProcessStartRequest>()))
-            .ReturnsAsync(() => new ProcessChangeResult() { Success = true });
+            .ReturnsAsync(() => new ProcessChangeResult() { Success = true, ProcessStateChange = new() });
         fixture
             .Mock<IProcessEngine>()
             .Setup(p =>
                 p.Start(
                     It.IsAny<Instance>(),
-                    It.IsAny<List<InstanceEvent>>(),
+                    It.IsAny<ProcessStateChange>(),
                     It.IsAny<System.Security.Claims.ClaimsPrincipal>(),
                     It.IsAny<Dictionary<string, string>>(),
                     It.IsAny<string>(),
@@ -952,7 +952,7 @@ public async Task CopyInstance_IncludeAttachmentsIsTrue_CopiesBinaryData()
             .ReturnsAsync(
                 (
                     Instance inst,
-                    List<InstanceEvent>? _,
+                    ProcessStateChange _,
                     System.Security.Claims.ClaimsPrincipal _,
                     Dictionary<string, string>? _,
                     string? _,
@@ -1154,13 +1154,13 @@ public async Task CopyInstance_OnlyBinaryData_NotCopiedByDefault()
         fixture
             .Mock<IProcessEngine>()
             .Setup(p => p.GenerateProcessStartEvents(It.IsAny<ProcessStartRequest>()))
-            .ReturnsAsync(() => new ProcessChangeResult() { Success = true });
+            .ReturnsAsync(() => new ProcessChangeResult() { Success = true, ProcessStateChange = new() });
         fixture
             .Mock<IProcessEngine>()
             .Setup(p =>
                 p.Start(
                     It.IsAny<Instance>(),
-                    It.IsAny<List<InstanceEvent>>(),
+                    It.IsAny<ProcessStateChange>(),
                     It.IsAny<System.Security.Claims.ClaimsPrincipal>(),
                     It.IsAny<Dictionary<string, string>>(),
                     It.IsAny<string>(),
@@ -1170,7 +1170,7 @@ public async Task CopyInstance_OnlyBinaryData_NotCopiedByDefault()
             .ReturnsAsync(
                 (
                     Instance inst,
-                    List<InstanceEvent>? _,
+                    ProcessStateChange _,
                     System.Security.Claims.ClaimsPrincipal _,
                     Dictionary<string, string>? _,
                     string? _,

test/Altinn.App.Core.Tests/PublicApiTests.PublicApi_ShouldNotChange_Unintentionally.verified.txt

@@ -3693,7 +3693,7 @@ namespace Altinn.App.Core.Internal.Process
         System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> GenerateProcessStartEvents(Altinn.App.Core.Models.Process.ProcessStartRequest processStartRequest);
         System.Threading.Tasks.Task<Altinn.Platform.Storage.Interface.Models.Instance> HandleEventsAndUpdateStorage(Altinn.Platform.Storage.Interface.Models.Instance instance, System.Collections.Generic.Dictionary<string, string>? prefill, System.Collections.Generic.List<Altinn.Platform.Storage.Interface.Models.InstanceEvent>? events);
         System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Next(Altinn.App.Core.Models.Process.ProcessNextRequest request, System.Threading.CancellationToken ct = default);
-        System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Start(Altinn.Platform.Storage.Interface.Models.Instance instance, System.Collections.Generic.List<Altinn.Platform.Storage.Interface.Models.InstanceEvent>? events, System.Security.Claims.ClaimsPrincipal user, System.Collections.Generic.Dictionary<string, string>? prefill = null, string? language = null, System.Threading.CancellationToken ct = default);
+        System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Start(Altinn.Platform.Storage.Interface.Models.Instance instance, Altinn.App.Core.Models.Process.ProcessStateChange processStateChange, System.Security.Claims.ClaimsPrincipal user, System.Collections.Generic.Dictionary<string, string>? prefill = null, string? language = null, System.Threading.CancellationToken ct = default);
     }
     public interface IProcessEngineAuthorizer
     {
@@ -3740,7 +3740,7 @@ namespace Altinn.App.Core.Internal.Process
         public System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> GenerateProcessStartEvents(Altinn.App.Core.Models.Process.ProcessStartRequest processStartRequest) { }
         public System.Threading.Tasks.Task<Altinn.Platform.Storage.Interface.Models.Instance> HandleEventsAndUpdateStorage(Altinn.Platform.Storage.Interface.Models.Instance instance, System.Collections.Generic.Dictionary<string, string>? prefill, System.Collections.Generic.List<Altinn.Platform.Storage.Interface.Models.InstanceEvent>? events) { }
         public System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Next(Altinn.App.Core.Models.Process.ProcessNextRequest request, System.Threading.CancellationToken ct = default) { }
-        public System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Start(Altinn.Platform.Storage.Interface.Models.Instance instance, System.Collections.Generic.List<Altinn.Platform.Storage.Interface.Models.InstanceEvent>? events, System.Security.Claims.ClaimsPrincipal user, System.Collections.Generic.Dictionary<string, string>? prefill = null, string? language = null, System.Threading.CancellationToken ct = default) { }
+        public System.Threading.Tasks.Task<Altinn.App.Core.Models.Process.ProcessChangeResult> Start(Altinn.Platform.Storage.Interface.Models.Instance instance, Altinn.App.Core.Models.Process.ProcessStateChange processStateChange, System.Security.Claims.ClaimsPrincipal user, System.Collections.Generic.Dictionary<string, string>? prefill = null, string? language = null, System.Threading.CancellationToken ct = default) { }
     }
     public class ProcessEventDispatcher : Altinn.App.Core.Internal.Process.IProcessEventDispatcher
     {