Incremental work on blueprints

src/core/Elsa.Abstractions/ActivityResults/OutcomeResult.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Elsa.Models;
 using Elsa.Services;
 using Elsa.Services.Models;
 
@@ -12,7 +13,7 @@ namespace Elsa.ActivityResults
         {
             var outcomeList = outcomes?.ToList() ?? new List<string>(1);
 
-            if (!outcomeList.Any()) 
+            if (!outcomeList.Any())
                 outcomeList.Add(OutcomeNames.Done);
 
             Outcomes = outcomeList;
@@ -24,24 +25,34 @@ namespace Elsa.ActivityResults
 
         protected override void Execute(ActivityExecutionContext activityExecutionContext)
         {
-            if(Output != null)
+            if (Output != null)
                 activityExecutionContext.Output = Output;
-            
+
             activityExecutionContext.Outcomes = Outcomes.ToList();
 
             var workflowExecutionContext = activityExecutionContext.WorkflowExecutionContext;
-            var nextActivities = GetNextActivities(workflowExecutionContext, activityExecutionContext.ActivityDefinition, Outcomes).ToList();
-            
+            var nextActivities = GetNextActivities(
+                workflowExecutionContext,
+                activityExecutionContext.ActivityDefinition,
+                Outcomes).ToList();
+
             workflowExecutionContext.ScheduleActivities(nextActivities, Output);
         }
-        
-        private IEnumerable<IActivity> GetNextActivities(WorkflowExecutionContext workflowContext, IActivity source, IEnumerable<string> outcomes)
+
+        private IEnumerable<ActivityDefinition> GetNextActivities(
+            WorkflowExecutionContext workflowContext,
+            ActivityDefinition source,
+            IEnumerable<string> outcomes)
         {
             var query =
-                from connection in workflowContext.Connections
+                from connection in workflowContext.WorkflowDefinition.Connections
                 from outcome in outcomes
-                where connection.Source.Activity == source && (connection.Source.Outcome ?? OutcomeNames.Done).Equals(outcome, StringComparison.OrdinalIgnoreCase)
-                select connection.Target.Activity;
+                let connectionOutcome = connection.Outcome ?? OutcomeNames.Done
+                let isConnectionOutcome = connectionOutcome.Equals(outcome, StringComparison.OrdinalIgnoreCase)
+                where connection.SourceActivityId == source.Id && isConnectionOutcome
+                from activityDefinition in workflowContext.WorkflowDefinition.Activities
+                where activityDefinition.Id == connection.TargetActivityId
+                select activityDefinition;
 
             return query.Distinct();
         }

src/core/Elsa.Abstractions/ActivityResults/ScheduleActivitiesResult.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using Elsa.Models;
 using Elsa.Services;
 using Elsa.Services.Models;
 using ScheduledActivity = Elsa.Services.Models.ScheduledActivity;
@@ -8,7 +9,7 @@ namespace Elsa.ActivityResults
 {
     public class ScheduleActivitiesResult : ActivityExecutionResult
     {
-        public ScheduleActivitiesResult(IEnumerable<IActivity> activities, object? input = default) => 
+        public ScheduleActivitiesResult(IEnumerable<ActivityDefinition> activities, object? input = default) => 
             Activities = activities.Select(x => new ScheduledActivity(x, input));
 
         public ScheduleActivitiesResult(IEnumerable<ScheduledActivity> activities) => Activities = activities;

src/core/Elsa.Abstractions/ActivityResults/SuspendResult.cs

@@ -1,3 +1,4 @@
+using Elsa.Models;
 using Elsa.Services.Models;
 
 namespace Elsa.ActivityResults
@@ -6,7 +7,9 @@ namespace Elsa.ActivityResults
     {
         protected override void Execute(ActivityExecutionContext activityExecutionContext)
         {
-            activityExecutionContext.WorkflowExecutionContext.BlockingActivities.Add(activityExecutionContext.ActivityDefinition);
+            var activityDefinition = activityExecutionContext.ActivityDefinition;
+            var blockingActivity = new BlockingActivity(activityDefinition.Id, activityDefinition.Type);
+            activityExecutionContext.WorkflowExecutionContext.BlockingActivities.Add(blockingActivity);
             activityExecutionContext.WorkflowExecutionContext.Suspend();
         }
     }

src/core/Elsa.Abstractions/Builders/IConnectionBuilder.cs

@@ -9,6 +9,6 @@ namespace Elsa.Builders
         Func<IActivityBuilder> Source { get; }
         Func<IActivityBuilder> Target{ get; }
         string Outcome { get; }
-        Connection BuildConnection();
+        //Connection BuildConnection();
     }
 }

src/core/Elsa.Abstractions/Extensions/WorkflowExecutionContextExtensions.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using Elsa.Models;
 using Elsa.Services;
 using Elsa.Services.Models;
 
@@ -18,23 +19,35 @@ namespace Elsa
         //
         //     return query;
         // }
-        
-        public static IEnumerable<Connection> GetInboundConnections(this WorkflowExecutionContext workflowExecutionContext, IActivity activity) => workflowExecutionContext.Connections.Where(x => x.Target.Activity == activity);
-        public static IEnumerable<Connection> GetOutboundConnections(this WorkflowExecutionContext workflowExecutionContext, IActivity activity) => workflowExecutionContext.Connections.Where(x => x.Source.Activity == activity);
-        public static IEnumerable<string> GetInboundActivityPath(this WorkflowExecutionContext workflowExecutionContext, IActivity activity) => workflowExecutionContext.GetInboundActivityPathInternal(activity, activity).Distinct();
 
-        private static IEnumerable<string> GetInboundActivityPathInternal(this WorkflowExecutionContext workflowExecutionContext, IActivity activity, IActivity startingPointActivity)
+        public static IEnumerable<ConnectionDefinition>
+            GetInboundConnections(this WorkflowExecutionContext workflowExecutionContext, string activityId) =>
+            workflowExecutionContext.WorkflowDefinition.Connections.Where(x => x.TargetActivityId == activityId);
+
+        public static IEnumerable<ConnectionDefinition> GetOutboundConnections(
+            this WorkflowExecutionContext workflowExecutionContext,
+            string activityId) =>
+            workflowExecutionContext.WorkflowDefinition.Connections.Where(x => x.SourceActivityId == activityId);
+
+        public static IEnumerable<string> GetInboundActivityPath(this WorkflowExecutionContext workflowExecutionContext,
+            string activityId) =>
+            workflowExecutionContext.GetInboundActivityPathInternal(activityId, activityId).Distinct();
+
+        private static IEnumerable<string> GetInboundActivityPathInternal(
+            this WorkflowExecutionContext workflowExecutionContext,
+            string activityId,
+            string startingPointActivityId)
         {
-            foreach (var connection in workflowExecutionContext.GetInboundConnections(activity))
+            foreach (var connection in workflowExecutionContext.GetInboundConnections(activityId))
             {
                 // Circuit breaker: Detect workflows that implement repeating flows to prevent an infinite loop here.
-                if (connection.Source.Activity == startingPointActivity)
+                if (connection.SourceActivityId == startingPointActivityId)
                     yield break;
 
-                yield return connection.Source.Activity.Id;
+                yield return connection.SourceActivityId!;
 
                 foreach (var parentActivityId in workflowExecutionContext
-                    .GetInboundActivityPathInternal(connection.Source.Activity, startingPointActivity)
+                    .GetInboundActivityPathInternal(connection.SourceActivityId!, startingPointActivityId)
                     .Distinct())
                     yield return parentActivityId;
             }

src/core/Elsa.Abstractions/Extensions/WorkflowExtensions.cs

@@ -8,10 +8,12 @@ namespace Elsa
 {
     public static class WorkflowExtensions
     {
-        public static IEnumerable<WorkflowBlueprint> WithVersion(this IEnumerable<WorkflowBlueprint> query, VersionOptions version) 
+        public static IEnumerable<WorkflowBlueprint> WithVersion(this IEnumerable<WorkflowBlueprint> query,
+            VersionOptions version)
             => query.AsQueryable().WithVersion(version);
 
-        public static IQueryable<WorkflowBlueprint> WithVersion(this IQueryable<WorkflowBlueprint> query, VersionOptions version)
+        public static IQueryable<WorkflowBlueprint> WithVersion(this IQueryable<WorkflowBlueprint> query,
+            VersionOptions version)
         {
             if (version.IsDraft)
                 query = query.Where(x => !x.IsPublished);
@@ -30,10 +32,11 @@ namespace Elsa
 
             return query.OrderByDescending(x => x.Version);
         }
-        
-        public static IEnumerable<IActivity> GetStartActivities(this WorkflowBlueprint workflowBlueprint)
+
+        public static IEnumerable<IActivityBlueprint> GetStartActivities(this WorkflowBlueprint workflowBlueprint)
         {
-            var targetActivityIds = workflowBlueprint.Connections.Select(x => x.Target.Activity.Id).Distinct().ToLookup(x => x);
+            var targetActivityIds = workflowBlueprint.Connections.Select(x => x.Target.Activity.Id).Distinct()
+                .ToLookup(x => x);
 
             var query =
                 from activity in workflowBlueprint.Activities
@@ -43,46 +46,50 @@ namespace Elsa
             return query;
         }
 
-        public static IActivity GetActivity(this WorkflowBlueprint workflowBlueprint, string id) => workflowBlueprint.Activities.FirstOrDefault(x => x.Id == id);
+        public static IActivityBlueprint? GetActivity(this WorkflowBlueprint workflowBlueprint, string id) =>
+            workflowBlueprint.Activities.FirstOrDefault(x => x.Id == id);
 
-        public static IEnumerable<Connection> GetInboundConnections(this WorkflowBlueprint workflowBlueprint, string activityId)
-        {
-            return workflowBlueprint.Connections.Where(x => x.Target.Activity.Id == activityId).ToList();
-        }
+        public static IEnumerable<IConnection> GetInboundConnections(
+            this WorkflowBlueprint workflowBlueprint,
+            string activityId) => workflowBlueprint.Connections.Where(x => x.Target.Activity.Id == activityId).ToList();
 
-        public static IEnumerable<Connection> GetOutboundConnections(this WorkflowBlueprint workflowBlueprint, string activityId)
-        {
-            return workflowBlueprint.Connections.Where(x => x.Source.Activity.Id == activityId).ToList();
-        }
+        public static IEnumerable<IConnection> GetOutboundConnections(
+            this WorkflowBlueprint workflowBlueprint,
+            string activityId) =>
+            workflowBlueprint.Connections.Where(x => x.Source.Activity.Id == activityId).ToList();
 
         /// <summary>
         /// Returns the full path of incoming activities.
         /// </summary>
-        public static IEnumerable<string> GetInboundActivityPath(this WorkflowBlueprint workflowBlueprint, string activityId)
+        public static IEnumerable<string> GetInboundActivityPath(
+            this WorkflowBlueprint workflowBlueprint,
+            string activityId)
         {
-            var inspectedActivityIDs = new HashSet<string>();
+            var inspectedActivityIds = new HashSet<string>();
 
-            return workflowBlueprint.GetInboundActivityPathInternal(activityId, activityId, inspectedActivityIDs)
-                           .Distinct().ToList();
+            return workflowBlueprint.GetInboundActivityPathInternal(activityId, inspectedActivityIds)
+                .Distinct().ToList();
         }
 
-        private static IEnumerable<string> GetInboundActivityPathInternal(this WorkflowBlueprint workflowBlueprintBlueprintInstance,
-            string activityId, 
-            string startingPointActivityId,
-            HashSet<string> inspectedActivityIDs)
+        private static IEnumerable<string> GetInboundActivityPathInternal(
+            this WorkflowBlueprint workflowBlueprintBlueprintInstance,
+            string activityId,
+            HashSet<string> inspectedActivityIds)
         {
             foreach (var connection in workflowBlueprintBlueprintInstance.GetInboundConnections(activityId))
             {
                 // Circuit breaker: Detect workflows that implement repeating flows to prevent an infinite loop here.
-                if (inspectedActivityIDs.Contains(connection.Source.Activity.Id))
+                if (inspectedActivityIds.Contains(connection.Source.Activity.Id))
                     yield break;
 
                 yield return connection.Source.Activity.Id;
 
-                foreach (var parentActivityId in workflowBlueprintBlueprintInstance.GetInboundActivityPathInternal(connection.Source.Activity.Id, startingPointActivityId, inspectedActivityIDs)
-                                                                 .Distinct())
+                foreach (var parentActivityId in workflowBlueprintBlueprintInstance.GetInboundActivityPathInternal(
+                        connection.Source.Activity.Id,
+                        inspectedActivityIds)
+                    .Distinct())
                 {
-                    inspectedActivityIDs.Add(parentActivityId);
+                    inspectedActivityIds.Add(parentActivityId);
                     yield return parentActivityId;
                 }
             }

src/core/Elsa.Abstractions/Messaging/Domain/ActivityNotification.cs

@@ -1,4 +1,5 @@
-using Elsa.Services;
+using Elsa.Models;
+using Elsa.Services;
 using Elsa.Services.Models;
 using MediatR;
 
@@ -13,6 +14,6 @@ namespace Elsa.Messaging.Domain
 
         public ActivityExecutionContext ActivityExecutionContext { get; }
         public WorkflowExecutionContext WorkflowExecutionContext => ActivityExecutionContext.WorkflowExecutionContext;
-        public IActivity Activity => ActivityExecutionContext.ActivityDefinition;
+        public ActivityDefinition Activity => ActivityExecutionContext.ActivityDefinition;
     }
 }

src/core/Elsa.Abstractions/Services/Activity.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using Elsa.ActivityResults;
+using Elsa.Models;
 using Elsa.Services.Models;
 using Microsoft.Extensions.Localization;
 using ScheduledActivity = Elsa.Services.Models.ScheduledActivity;
@@ -40,9 +41,9 @@ namespace Elsa.Services
         protected OutcomeResult Done(params string[] outcomes) => Done(outcomes, default);
         protected OutcomeResult Done(object? output) => new OutcomeResult(null, output);
         protected SuspendResult Suspend() => new SuspendResult();
-        protected ScheduleActivitiesResult Schedule(params IActivity[] activities) => new ScheduleActivitiesResult(activities);
-        protected ScheduleActivitiesResult Schedule(IEnumerable<IActivity> activities, object input) => new ScheduleActivitiesResult(activities, input);
-        protected ScheduleActivitiesResult Schedule(IActivity activity, object input) => Schedule(new[] { activity }, input);
+        protected ScheduleActivitiesResult Schedule(params ActivityDefinition[] activities) => new ScheduleActivitiesResult(activities);
+        protected ScheduleActivitiesResult Schedule(IEnumerable<ActivityDefinition> activities, object input) => new ScheduleActivitiesResult(activities, input);
+        protected ScheduleActivitiesResult Schedule(ActivityDefinition activity, object input) => Schedule(new[] { activity }, input);
         protected ScheduleActivitiesResult Schedule(IEnumerable<ScheduledActivity> activities) => new ScheduleActivitiesResult(activities);
         protected CombinedResult Combine(IEnumerable<IActivityExecutionResult> results) => new CombinedResult(results);
         protected CombinedResult Combine(params IActivityExecutionResult[] results) => new CombinedResult(results);

src/core/Elsa.Abstractions/Services/Models/Connection.cs

@@ -2,7 +2,7 @@ namespace Elsa.Services.Models
 {
     public class Connection : IConnection
     {
-        public Connection(IActivity sourceActivity, IActivity targetActivity, string sourceOutcome)
+        public Connection(IActivityBlueprint sourceActivity, IActivityBlueprint targetActivity, string sourceOutcome)
             : this(new SourceEndpoint(sourceActivity, sourceOutcome), new TargetEndpoint(targetActivity))
         {
         }

src/core/Elsa.Abstractions/Services/Models/Endpoint.cs

@@ -2,15 +2,11 @@ namespace Elsa.Services.Models
 {
     public abstract class Endpoint
     {
-        protected Endpoint()
-        {
-        }
-
-        protected Endpoint(IActivity activity)
+        protected Endpoint(IActivityBlueprint activity)
         {
             Activity = activity;
         }
         
-        public IActivity Activity { get; set; }
+        public IActivityBlueprint Activity { get; set; }
     }
 }

src/core/Elsa.Abstractions/Services/Models/IEndpoint.cs

@@ -2,6 +2,6 @@
 {
     public interface IEndpoint
     {
-        IActivity Activity { get; }
+        IActivityBlueprint Activity { get; }
     }
 }

src/core/Elsa.Abstractions/Services/Models/IWorkflowFault.cs

@@ -1,10 +1,11 @@
-using Microsoft.Extensions.Localization;
+using Elsa.Models;
+using Microsoft.Extensions.Localization;
 
 namespace Elsa.Services.Models
 {
     public interface IWorkflowFault
     {
-        IActivity? FaultedActivity { get; }
+        ActivityDefinition? FaultedActivity { get; }
         LocalizedString? Message { get; }
     }
 }

src/core/Elsa.Abstractions/Services/Models/SourceEndpoint.cs

@@ -2,7 +2,7 @@ namespace Elsa.Services.Models
 {
     public class SourceEndpoint : Endpoint, ISourceEndpoint
     {
-        public SourceEndpoint(IActivity activity, string outcome) : base(activity) => Outcome = outcome;
+        public SourceEndpoint(IActivityBlueprint activity, string outcome) : base(activity) => Outcome = outcome;
         public string Outcome { get; set; }
     }
 }

src/core/Elsa.Abstractions/Services/Models/TargetEndpoint.cs

@@ -2,7 +2,7 @@ namespace Elsa.Services.Models
 {
     public class TargetEndpoint : Endpoint, ITargetEndpoint
     {
-        public TargetEndpoint(IActivity activity) : base(activity)
+        public TargetEndpoint(IActivityBlueprint activity) : base(activity)
         {
         }
     }

src/core/Elsa.Abstractions/Services/Models/WorkflowExecutionContext.cs

@@ -98,7 +98,7 @@ namespace Elsa.Services.Models
 
         public void Suspend() => Status = WorkflowStatus.Suspended;
 
-        public void Fault(IActivity? activity, LocalizedString? message)
+        public void Fault(ActivityDefinition? activity, LocalizedString? message)
         {
             Status = WorkflowStatus.Faulted;
             WorkflowFault = new WorkflowFault(activity, message);
@@ -106,7 +106,7 @@ namespace Elsa.Services.Models
 
         public void Complete() => Status = WorkflowStatus.Completed;
 
-        public IActivity? GetActivity(string id) => WorkflowBlueprint.Activities.FirstOrDefault(x => x.Id == id);
+        public IActivityBlueprint? GetActivity(string id) => WorkflowBlueprint.Activities.FirstOrDefault(x => x.Id == id);
 
         public void UpdateWorkflowInstance(WorkflowInstance workflowInstance)
         {
@@ -115,8 +115,8 @@ namespace Elsa.Services.Models
             workflowInstance.ScheduledActivities = new Stack<Elsa.Models.ScheduledActivity>(
                 ScheduledActivities.Select(x => new Elsa.Models.ScheduledActivity(x.ActivityDefinition.Id, x.Input)));
 
-            workflowInstance.Activities =
-                WorkflowBlueprint.Activities.Select(x => new ActivityInstance(x.Id, x.Type, x.Output, Serialize(x))).ToList();
+            //workflowInstance.Activities =
+            //    WorkflowBlueprint.Activities.Select(x => new ActivityInstance(x.Id, x.Type, x.Output, Serialize(x))).ToList();
 
             workflowInstance.BlockingActivities = BlockingActivities;
             workflowInstance.Status = Status;

src/core/Elsa.Abstractions/Services/Models/WorkflowFault.cs

@@ -1,16 +1,17 @@
-using Microsoft.Extensions.Localization;
+using Elsa.Models;
+using Microsoft.Extensions.Localization;
 
 namespace Elsa.Services.Models
 {
     public class WorkflowFault : IWorkflowFault
     {
-        public WorkflowFault(IActivity? activity = default, LocalizedString? message = default)
+        public WorkflowFault(ActivityDefinition? activity = default, LocalizedString? message = default)
         {
             FaultedActivity = activity;
             Message = message;
         }
 
-        public IActivity? FaultedActivity { get; }
+        public ActivityDefinition? FaultedActivity { get; }
         public LocalizedString? Message { get; }
     }
 }

src/core/Elsa.Core/Activities/ControlFlow/For/For.cs

@@ -1,6 +1,7 @@
 using Elsa.ActivityResults;
 using Elsa.Attributes;
 using Elsa.Services;
+using Elsa.Services.Models;
 
 // ReSharper disable once CheckNamespace
 namespace Elsa.Activities.ControlFlow
@@ -24,7 +25,7 @@ namespace Elsa.Activities.ControlFlow
 
         private int? CurrentValue { get; set; }
 
-        protected override IActivityExecutionResult OnExecute()
+        protected override IActivityExecutionResult OnExecute(ActivityExecutionContext context)
         {
             var currentValue = CurrentValue ?? Start;
 
@@ -33,7 +34,7 @@ namespace Elsa.Activities.ControlFlow
                 var input = currentValue;
                 currentValue += Step;
                 CurrentValue = currentValue;
-                return Combine(Schedule(this), Done(OutcomeNames.Iterate, input));
+                return Combine(Schedule(context.ActivityDefinition), Done(OutcomeNames.Iterate, input));
             }
 
             CurrentValue = null;

src/core/Elsa.Core/Activities/ControlFlow/ForEach/ForEach.cs

@@ -16,7 +16,7 @@ namespace Elsa.Activities.ControlFlow
         Category = "Control Flow",
         Description = "Iterate over a collection.",
         Icon = "far fa-circle",
-        Outcomes = new[] {OutcomeNames.Iterate, OutcomeNames.Done}
+        Outcomes = new[] { OutcomeNames.Iterate, OutcomeNames.Done }
     )]
     public class ForEach : Activity
     {
@@ -27,9 +27,7 @@ namespace Elsa.Activities.ControlFlow
 
         private int? CurrentIndex { get; set; }
 
-        protected override async Task<IActivityExecutionResult> OnExecuteAsync(
-            ActivityExecutionContext context,
-            CancellationToken cancellationToken)
+        protected override IActivityExecutionResult OnExecute(ActivityExecutionContext context)
         {
             var collection = CollectionCopy;
 
@@ -42,7 +40,7 @@ namespace Elsa.Activities.ControlFlow
             {
                 var input = collection[currentIndex];
                 CurrentIndex = currentIndex + 1;
-                return Combine(Schedule(this), Done(OutcomeNames.Iterate, input));
+                return Combine(Schedule(context.ActivityDefinition), Done(OutcomeNames.Iterate, input));
             }
 
             CurrentIndex = null;

src/core/Elsa.Core/Activities/ControlFlow/Fork/ForkBuilder.cs

@@ -11,7 +11,7 @@ namespace Elsa.Activities.ControlFlow
         public ForkBuilder(IActivityBuilder activityBuilder)
         {
             _activityBuilder = activityBuilder;
-            _fork = (Fork)activityBuilder.Activity;
+            //_fork = (Fork)activityBuilder.Activity;
         }
 
         public IOutcomeBuilder When(string branch)

src/core/Elsa.Core/Activities/ControlFlow/Fork/ForkBuilderExtensions.cs

@@ -8,11 +8,12 @@ namespace Elsa.Activities.ControlFlow
     {
         public static IWorkflowBuilder Fork(this IBuilder builder, Action<ForkBuilder> setup)
         {
-            var activityBuilder = builder.Then<Fork>();
-            var forkBuilder = new ForkBuilder(activityBuilder);
+            //var activityBuilder = builder.Then<Fork>();
+            //var forkBuilder = new ForkBuilder(activityBuilder);
             
-            setup(forkBuilder);
-            return activityBuilder.WorkflowBuilder;
+            //setup(forkBuilder);
+            //return activityBuilder.WorkflowBuilder;
+            throw new NotImplementedException();
         }
     }
 }

src/core/Elsa.Core/Activities/Primitives/Inline.cs

@@ -12,40 +12,8 @@ namespace Elsa.Activities.Primitives
     /// </summary>
     public class Inline : Activity
     {
-        public Inline()
-        {
-            Function = context => Task.FromResult<IActivityExecutionResult>(Done());
-        }
-
-        public Inline(Func<ActivityExecutionContext, Task<IActivityExecutionResult>> function)
-        {
-            Function = function;
-        }
-        
-        public Inline(Func<ActivityExecutionContext, Task> function)
-        {
-            Function = context =>
-            {
-                function(context);
-                return Task.FromResult<IActivityExecutionResult>(Done());
-            };
-        }
-        
-        public Inline(Action<ActivityExecutionContext> function)
-        {
-            Function = context =>
-            {
-                function(context);
-                return Task.FromResult<IActivityExecutionResult>(Done());
-            };
-        }
-        
-        public Inline(Action function) : this(context => function())
-        {
-        }
-        
-        public Func<ActivityExecutionContext, Task<IActivityExecutionResult>> Function { get; set; }
-
-        protected override Task<IActivityExecutionResult> OnExecuteAsync(ActivityExecutionContext context, CancellationToken cancellationToken) => Function(context);
+        public Inline() => Function = context => new ValueTask<IActivityExecutionResult>(Done());
+        public Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> Function { get; set; }
+        protected override ValueTask<IActivityExecutionResult> OnExecuteAsync(ActivityExecutionContext context, CancellationToken cancellationToken) => Function(context);
     }
 }

src/core/Elsa.Core/Builders/ActivityBuilderExtensions.cs

@@ -8,9 +8,57 @@ namespace Elsa.Builders
 {
     public static class ActivityBuilderExtensions
     {
-        public static IActivityBuilder Then(this IBuilder builder, Func<ActivityExecutionContext, Task<IActivityExecutionResult>> activity) => builder.Then(new Inline(activity));
-        public static IActivityBuilder Then(this IBuilder builder, Func<ActivityExecutionContext, Task> activity) => builder.Then(new Inline(activity));
-        public static IActivityBuilder Then(this IBuilder builder, Action<ActivityExecutionContext> activity) => builder.Then(new Inline(activity));
-        public static IActivityBuilder Then(this IBuilder builder, Action activity) => builder.Then(new Inline(activity));
+        public static IActivityBuilder Then(this IBuilder builder,
+            Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> activity) =>
+            builder.Then<Inline>(x => x.Function = RunInline(activity));
+
+        public static IActivityBuilder
+            Then(this IBuilder builder, Func<ActivityExecutionContext, ValueTask> activity) =>
+            builder.Then<Inline>(x => x.Function = RunInline(activity));
+
+        public static IActivityBuilder Then(this IBuilder builder, Action<ActivityExecutionContext> activity) =>
+            builder.Then<Inline>(x => x.Function = RunInline(activity));
+
+        public static IActivityBuilder Then(this IBuilder builder, Action activity) =>
+            builder.Then<Inline>(x => x.Function = RunInline(activity));
+
+        private static Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> RunInline(
+            Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> activity) =>
+            async context =>
+            {
+                await activity(context);
+                return new OutcomeResult();
+            };
+
+        private static Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> RunInline(
+            Func<ActivityExecutionContext, ValueTask> activity) =>
+            async context =>
+            {
+                await activity(context);
+                return new OutcomeResult();
+            };
+
+        private static Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> RunInline(
+            Action<ActivityExecutionContext> activity) =>
+            context =>
+            {
+                activity(context);
+                return new ValueTask<IActivityExecutionResult>(new OutcomeResult());
+            };
+
+        private static Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> RunInline(
+            Func<ActivityExecutionContext, Task> activity) =>
+            async context =>
+            {
+                await activity(context);
+                return new OutcomeResult();
+            };
+
+        private static Func<ActivityExecutionContext, ValueTask<IActivityExecutionResult>> RunInline(Action activity) =>
+            context =>
+            {
+                activity();
+                return new ValueTask<IActivityExecutionResult>(new OutcomeResult());
+            };
     }
 }

src/core/Elsa.Core/Builders/ConnectionBuilder.cs

@@ -18,6 +18,6 @@ namespace Elsa.Builders
             Outcome = outcome;
         }
 
-        public Connection BuildConnection() => new Connection(Source().Activity, Target().Activity, Outcome);
+        //public Connection BuildConnection() => new Connection(Source, Target().Activity, Outcome);
     }
 }