+semver:minor - Simplify Starting Modules (#361)

* Simplify Starting Modules

* Formatting Markdown

---------

Co-authored-by: Tom Longhurst <thomhurst@users.noreply.github.com>

Author: thomhurst

src/ModularPipelines/Engine/Executors/ModuleHandlers/SkipHandler.cs

@@ -24,8 +24,6 @@ public async Task SetSkipped(SkipDecision skipDecision)
         {
             return;
         }
-
-        Module.ExecutionTask = ModuleResultTaskCompletionSource.Task;
 
         CallbackTask.Start(TaskScheduler.Default);
 

src/ModularPipelines/Engine/ModuleExecutor.cs

@@ -83,7 +83,7 @@ public async Task<ModuleBase> ExecuteAsync(ModuleBase module)
         {
             await _pipelineSetupExecutor.OnBeforeModuleStartAsync(module);
 
-            await module.StartAsync();
+            await module.ExecutionTask;
 
             await _moduleEstimatedTimeProvider.SaveModuleTimeAsync(module.GetType(), module.Duration);
 

src/ModularPipelines/Modules/Module.cs

@@ -24,7 +24,6 @@ public abstract partial class Module<T> : ModuleBase<T>
 {
     private readonly Stopwatch _stopwatch = new();
     private readonly object _startCheckLock = new();
-    private readonly object _triggerLock = new();
 
     internal override IHistoryHandler<T> HistoryHandler { get; }
 
@@ -61,20 +60,6 @@ protected Module()
         }
     }
 
-    /// <summary>
-    /// Used to start, run, and control the flow of a Module, including handling exceptions and skipping.
-    /// </summary>
-    /// <exception cref="ModuleFailedException">Thrown if the module has failed and the failure was not ignored.</exception>
-    [StackTraceHidden]
-    internal override Task StartAsync()
-    {
-        lock (_startCheckLock)
-        {
-            IsStarted = true;
-            return ExecutionTask;
-        }
-    }
-
     internal override ModuleBase Initialize(IPipelineContext context)
     {
         context.InitializeLogger(GetType());
@@ -102,20 +87,20 @@ internal override Task ExecutionTask
         [StackTraceHidden]
         get
         {
-            lock (_triggerLock)
+            lock (_startCheckLock)
             {
-                _executionTaskInternal ??= StartInternal();
+                if (!IsStarted)
+                {
+#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                    StartInternal();
+#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+                }
+
+                IsStarted = true;
+                
                 return ModuleResultTaskCompletionSource.Task;
             }
         }
-
-        set
-        {
-            lock (_triggerLock)
-            {
-                _executionTaskInternal = value;
-            }
-        }
     }
 
     /// <summary>
@@ -187,8 +172,6 @@ private void AddDependency(DependsOnAttribute dependsOnAttribute)
         DependentModules.Add(dependsOnAttribute);
     }
 
-    private Task? _executionTaskInternal;
-
     [StackTraceHidden]
     private async Task StartInternal()
     {

src/ModularPipelines/Modules/ModuleBase.cs

@@ -26,9 +26,9 @@ protected ModuleBase()
         TypeDiscriminator = GetType().FullName!;
     }
 
-    internal bool IsStarted { get; set; }
+    internal bool IsStarted { get; private protected set; }
 
-    internal List<DependsOnAttribute> DependentModules { get; } = new();
+    internal List<DependsOnAttribute> DependentModules { get; } = [];
 
     internal abstract IWaitHandler WaitHandler { get; }
 
@@ -73,7 +73,7 @@ protected set
     [JsonInclude]
     internal SkipDecision SkipResult { get; set; } = SkipDecision.DoNotSkip;
 
-    internal abstract Task ExecutionTask { get; set; }
+    internal abstract Task ExecutionTask { get; }
 
     internal readonly CancellationTokenSource ModuleCancellationTokenSource = new();
 
@@ -103,9 +103,6 @@ protected set
 
     internal Exception? Exception { get; set; }
 
-    [StackTraceHidden]
-    internal abstract Task StartAsync();
-
     internal abstract ModuleBase Initialize(IPipelineContext context);
 
     internal readonly List<SubModuleBase> SubModuleBases = new();