-

src/Test/TestCases.Workflows/Bpm/FlowchartTestExtensions.cs

@@ -1,28 +1,24 @@
 using System.Activities;
 using System.Activities.Statements;
 using System;
+using System.Linq;
 
 namespace TestCases.Activitiess.Bpm;
 
 public static class FlowchartTestExtensions
 {
     public static FlowSplit AddBranches(this FlowSplit split, params Activity[] nodes)
     {
-        foreach(var node in nodes)
-        {
-            var branch = FlowSplitBranch.New(split);
-            branch.StartNode = new FlowStep() { Action = node, Next = branch.StartNode };
-            split.Branches.Add(branch);
-        }
-        return split;
+        return split.AddBranches(nodes.Select(a => new FlowStep { Action = a }).ToArray());
     }
     public static FlowSplit AddBranches(this FlowSplit split, params FlowNode[] nodes)
     {
         foreach (var node in nodes)
         {
-            var branch = FlowSplitBranch.New(split);
-            node.FlowTo(split.MergeNode);
-            branch.StartNode = node;
+            var branch = new FlowSplitBranch()
+            {
+                StartNode = node,
+            };
             split.Branches.Add(branch);
         }
         return split;
@@ -31,6 +27,10 @@ public static FlowStep Step(this Activity activity)
     {
         return new FlowStep { Action = activity };
     }
+    public static FlowMerge Merge(this Activity activity)
+    {
+        return new () { Next = new FlowStep() { Action = activity } };
+    }
 
     public static FlowStep FlowTo(this Activity predeccessor, FlowNode successor)
     {
@@ -40,6 +40,19 @@ public static FlowStep FlowTo(this Activity predeccessor, Activity successor)
     {
         return new FlowStep { Action = predeccessor }.FlowTo(successor);
     }
+    public static FlowMerge MergeTo(this FlowSplit split, FlowNode successor)
+    {
+        var merge = new FlowMerge() { Next = successor };
+        foreach (var branch in split.Branches)
+        {
+            branch.StartNode.FlowTo(merge);
+        }
+        return merge;
+    }
+    public static FlowMerge MergeTo(this FlowSplit split, Activity successor)
+    {
+        return split.MergeTo(new FlowStep { Action = successor });
+    }
     public static T FlowTo<T>(this T predeccessor, Activity successor)
         where T : FlowNode
     {
@@ -59,7 +72,10 @@ public static T FlowTo<T>(this T predeccessor, FlowNode successor)
                 (join.Next ??= successor).FlowTo(successor);
                 break;
             case FlowSplit split:
-                (split.MergeNode.Next ??= successor).FlowTo(successor);
+                foreach (var branch in split.Branches)
+                {
+                    branch.StartNode.FlowTo(successor);
+                }
                 break;
             case FlowDecision decision:
                 (decision.True ??= successor).FlowTo(successor);

src/Test/TestCases.Workflows/Bpm/SplitAndMergeTests.cs

@@ -9,7 +9,7 @@
 using TestObjects.XamlTestDriver;
 using System.IO;
 using System;
-
+using WorkflowApplicationTestExtensions;
 namespace TestCases.Activitiess.Bpm;
 
 public class AddStringActivity : NativeActivity
@@ -25,7 +25,7 @@ protected override void Execute(NativeActivityContext context)
     {
         using var _ = context.InheritVariables();
         var stringsLocation = context.GetInheritedLocation<List<string>>("strings");
-        stringsLocation.Value ??= new();
+        stringsLocation.Value ??= [];
         stringsLocation.Value.Add(Item);
     }
 }
@@ -37,7 +37,7 @@ public class SplitAndMergeTests
 
     private AddStringActivity AddString(string stringToAdd)
     {
-        var act = new AddStringActivity() { Item = stringToAdd };
+        var act = new AddStringActivity() { Item = stringToAdd, DisplayName = stringToAdd };
         return act;
     }
 
@@ -50,7 +50,8 @@ private List<string> ExecuteFlowchart(FlowNode startNode)
     private List<string> ExecuteFlowchart(Flowchart flowchart)
     {
         var root = new ActivityWithResult<List<string>> { Body = flowchart, In = _stringsVariable };
-        return Results = WorkflowInvoker.Invoke(root);
+        var app = new WorkflowApplication(root);
+        return Results = (List<string>) app.RunUntilCompletion().Outputs["Result"];
     }
 
     [Fact]
@@ -101,7 +102,7 @@ public void Should_join_branches()
                 AddString(branch1Str),
                 AddString(branch2Str)
                 );
-        split.MergeNode.FlowTo(AddString(stopString));
+        split.MergeTo(AddString(stopString));
 
         ExecuteFlowchart(split);
         Results.ShouldBe(new() { branch1Str, branch2Str, stopString });
@@ -110,21 +111,27 @@ public void Should_join_branches()
     [Fact]
     public void Should_join_branches_with_inner_split()
     {
+        ///                      |--A--|
+        ///        |---A---Split<      Merge--|
+        ///  Split<              |--A--|      Merge---Stop
+        ///        |___A______________________|
+
+        var outerMerge = AddString("stop").Merge();
+        var innerMerge = AddString("innerMerged").Merge();
         var innerSplit = new FlowSplit()
             .AddBranches(
-                AddString("branch1Inner"),
-                AddString("branch2Inner")
+                AddString("branch1Inner").FlowTo(innerMerge),
+                AddString("branch2Inner").FlowTo(innerMerge)
                 );
-        innerSplit.MergeNode.FlowTo(AddString("innerMerged"));
+        innerMerge.FlowTo(outerMerge);
         var outerSplit = new FlowSplit()
             .AddBranches(
-                innerSplit,
-                AddString("branch2Outer").Step()
+                AddString("branch1Outer").FlowTo(innerSplit),
+                AddString("branch2Outer").Step().FlowTo(outerMerge)
                 );
-        outerSplit.MergeNode.FlowTo(AddString("stop"));
 
         ExecuteFlowchart(outerSplit);
-        Results.ShouldBe(new() { "branch1Inner", "branch2Inner", "innerMerged", "branch2Outer", "stop"});
+        Results.ShouldBe(["branch1Outer", "branch1Inner", "branch2Inner", "innerMerged", "branch2Outer", "stop"]);
     }
 
 
@@ -141,7 +148,7 @@ public void Should_join_with_skiped_branches()
                 AddString(branch2Str)
                 );
         split.Branches.First().Condition = new LambdaValue<bool>(c => false);
-        split.MergeNode.FlowTo(AddString(stopString));
+        split.MergeTo(AddString(stopString));
 
         ExecuteFlowchart(split);
         Results.ShouldBe(new() { branch2Str, stopString });
@@ -159,8 +166,8 @@ public void Should_join_branches_when_condition_is_met()
                 AddString(branch1Str).FlowTo(AddString(branch1Str)),
                 new BlockingActivity("whatever").FlowTo(AddString(branch2Str))
                 );
-        split.MergeNode.FlowTo(AddString(stopString));
-        split.MergeNode.Completion = new LambdaValue<bool>(c => true);
+        split.MergeTo(AddString(stopString))
+            .Completion = new LambdaValue<bool>(c => true);
 
         ExecuteFlowchart(split);
         Results.ShouldBe(new() { branch1Str, branch1Str, stopString });
@@ -209,7 +216,7 @@ ActivityWithResult<List<string>> ParallelActivities()
                 AddString(branch1Str).FlowTo(new FlowStep()),
                 AddString(branch2Str).FlowTo(new FlowStep()),
                 blockingActivity.FlowTo(blockingContinuation).FlowTo(new FlowStep()));
-            split.MergeNode.FlowTo(AddString(stopString));
+            split.MergeTo(AddString(stopString));
             var flowchart = new Flowchart { StartNode = split };
             return new() { In = _stringsVariable, Body = flowchart };
         }

src/Test/TestCases.Workflows/TestCases.Workflows.csproj

@@ -4,6 +4,7 @@
     <ProjectReference Include="..\CustomTestObjects\CustomTestObjects.csproj" />
     <ProjectReference Include="..\JsonFileInstanceStore\JsonFileInstanceStore.csproj" />
     <ProjectReference Include="..\TestObjects\TestObjects.csproj" />
+    <ProjectReference Include="..\WorkflowApplicationTestExtensions\WorkflowApplicationTestExtensions.csproj" />
   </ItemGroup>
   <ItemGroup>
     <Page Remove="**\*.xaml" />

src/UiPath.Workflow.Runtime/Statements/FlowMerge.cs

@@ -1,28 +1,16 @@
-using System.Linq;
+using System.Activities.Validation;
+using System.Linq;
 namespace System.Activities.Statements;
 
 public class FlowMerge : FlowNode
 {
-    private FlowSplit _split;
     [DefaultValue(null)]
     public Activity<bool> Completion { get; set; }
     [DefaultValue(null)]
     public FlowNode Next { get; set; }
-    public FlowSplit SplitNode
-    {
-        get => _split;
-        init
-        {
-            if (value?.MergeNode is { } merge && merge != this)
-                    throw new InvalidOperationException("Split and merge must be linked both ways.");
-            _split = value;
-        }
-    }
-
 
     internal override Activity ChildActivity => Completion;
-
-    private List<Flowchart.BranchLinks> ConnectedBranches { get; set; }
+    private List<FlowSplitBranch> ConnectedBranches { get; set; }
 
     private record MergeState
     {
@@ -37,37 +25,24 @@ public FlowMerge()
     protected override void OnEndCacheMetadata()
     {
         var predecessors = Owner.GetPredecessors(this);
-        ConnectedBranches = predecessors.Select(p => Owner.GetBranch(p)).ToList();
+        ConnectedBranches = predecessors.SelectMany(p => Owner.GetStaticBranches(p)).Distinct().ToList();
+        var outgoingBranches = ConnectedBranches.SelectMany(b => Owner.GetStaticBranches(b.SplitNode)).Distinct().ToList();
+        Owner.AddStaticBranches(this, outgoingBranches);
 
-        ValidateAllBranches();
+        //ValidateAllBranches();
 
         void ValidateAllBranches()
         {
-            HashSet<FlowNode> visited = new()
-            {
-                this,
-                _split,
-            };
-            List<FlowNode> toVisit = new(1) { this };
-            do
+            var splits = ConnectedBranches.Select(bl => bl.SplitNode).Distinct().ToList();
+            if (splits.Count() > 1)
             {
-                var predecessors = toVisit.SelectMany(v => Owner.GetPredecessors(v)).ToList();
-                toVisit = new List<FlowNode>(predecessors.Count);
-                foreach (var predecessor in predecessors)
-                {
-                    if (!visited.Add(predecessor))
-                        continue;
-                    if (predecessor == null)
-                    {
-                        Metadata.AddValidationError("All join branches should start in the parent parallel node.");
-                        continue;
-                    }
-                    toVisit.Add(predecessor);
-                }
+                Metadata.AddValidationError("All join branches should start in the same parallel node.");
             }
-            while (toVisit.Any());
-            var allBranchesJoined = _split.Branches.All(b => visited.Contains(b.StartNode));
-            if (!allBranchesJoined)
+            var split = splits.FirstOrDefault();
+            if (split is null)
+                return;
+            var branches = ConnectedBranches.Select(b => b.RuntimeNode.Index).Distinct().ToList();
+            if (branches.Count != split.Branches.Count) 
                 Metadata.AddValidationError("All parallel branches should end in same join node.");
         }
     }
@@ -79,7 +54,7 @@ internal override void GetConnectedNodes(IList<FlowNode> connections)
         }
     }
 
-    MergeState GetJoinState(Func<MergeState> add = null)
+    MergeState GetJoinState()
     {
         var key = $"{Index}";
         var joinStates = Owner.GetPersistableState<Dictionary<string, MergeState>>("FlowMerge");
@@ -100,7 +75,11 @@ internal override void Execute(FlowNode predecessorNode)
         var branch = Owner.GetBranch(predecessorNode);
         if (!ConnectedBranches.Contains(branch))
             return;
-        joinState.CompletedNodeIndeces.Add(branch.NodeIndex);
+        joinState.CompletedNodeIndeces.Add(branch.RuntimeNode.Index);
+        joinState.CompletedNodeIndeces
+            .AddRange(Owner
+            .GetCompletedBranches()
+            .Select(b => b.RuntimeNode.Index));
         if (Completion is not null)
         {
             Owner.ScheduleWithCallback(Completion);
@@ -114,7 +93,7 @@ protected override void OnCompletionCallback(bool result)
     {
         var joinState = GetJoinState();
         var incompleteBranches = ConnectedBranches
-            .Select(b => b.NodeIndex)
+            .Select(b => b.RuntimeNode.Index)
             .Except(joinState.CompletedNodeIndeces).ToList();
         if (result)
         {