fix: keep nested inheritance split tails outside cases

Symptom: describing a microflow with an inheritance split inside an if could emit the parent continuation inside the matching split case. Re-executing that MDL made variables declared in the continuation branch-scoped, so Mendix mx check reported invalid or missing return/variable state.

Root cause: nested inheritance split emission stopped branches only at the split's own merge. When the inheritance split had no merge because one branch returned and the other fell through to the parent if merge, branch traversal used an empty stop ID and consumed the parent tail.

Fix: when emitting an inheritance split, prefer the split's own merge but fall back to the caller's stop ID. This keeps parent continuation statements outside the split cases while preserving standalone inheritance split behavior.

Tests: added a synthetic nested if/split-type traversal regression that verifies the parent tail is emitted after both end split and end if.

Author: hjothamendix

mdl/executor/cmd_microflows_inheritance_test.go

@@ -150,6 +150,92 @@ func TestTraverseFlow_InheritanceSplitPreservesExplicitCaseOrder(t *testing.T) {
 	}
 }
 
+func TestTraverseFlow_NestedInheritanceSplitKeepsParentTailOutsideCase(t *testing.T) {
+	e := newTestExecutor()
+	entityID := mkID("entity-specialized")
+
+	activityMap := map[model.ID]microflows.MicroflowObject{
+		mkID("start"): &microflows.StartEvent{BaseMicroflowObject: mkObj("start")},
+		mkID("init"): &microflows.ActionActivity{
+			BaseActivity: microflows.BaseActivity{BaseMicroflowObject: mkObj("init")},
+			Action: &microflows.CreateVariableAction{
+				VariableName: "TokenValue",
+				InitialValue: "''",
+			},
+		},
+		mkID("outer_split"): &microflows.ExclusiveSplit{
+			BaseMicroflowObject: mkObj("outer_split"),
+			SplitCondition:      &microflows.ExpressionSplitCondition{Expression: "$UseToken"},
+		},
+		mkID("before_type_split"): &microflows.ActionActivity{
+			BaseActivity: microflows.BaseActivity{BaseMicroflowObject: mkObj("before_type_split")},
+			Action:       &microflows.LogMessageAction{LogLevel: "Info", LogNodeName: "'App'", MessageTemplate: &model.Text{Translations: map[string]string{"en_US": "before type split"}}},
+		},
+		mkID("type_split"): &microflows.InheritanceSplit{
+			BaseMicroflowObject: mkObj("type_split"),
+			VariableName:        "Input",
+		},
+		mkID("set_token"): &microflows.ActionActivity{
+			BaseActivity: microflows.BaseActivity{BaseMicroflowObject: mkObj("set_token")},
+			Action:       &microflows.ChangeVariableAction{VariableName: "TokenValue", Value: "$Input/Value"},
+		},
+		mkID("failed_log"): &microflows.ActionActivity{
+			BaseActivity: microflows.BaseActivity{BaseMicroflowObject: mkObj("failed_log")},
+			Action:       &microflows.LogMessageAction{LogLevel: "Info", LogNodeName: "'App'", MessageTemplate: &model.Text{Translations: map[string]string{"en_US": "no token"}}},
+		},
+		mkID("failed_return"): &microflows.EndEvent{
+			BaseMicroflowObject: mkObj("failed_return"),
+			ReturnValue:         "empty",
+		},
+		mkID("outer_merge"): &microflows.ExclusiveMerge{BaseMicroflowObject: mkObj("outer_merge")},
+		mkID("tail"): &microflows.ActionActivity{
+			BaseActivity: microflows.BaseActivity{BaseMicroflowObject: mkObj("tail")},
+			Action:       &microflows.LogMessageAction{LogLevel: "Info", LogNodeName: "'App'", MessageTemplate: &model.Text{Translations: map[string]string{"en_US": "tail after split"}}},
+		},
+		mkID("end"): &microflows.EndEvent{
+			BaseMicroflowObject: mkObj("end"),
+			ReturnValue:         "'ok'",
+		},
+	}
+	flowsByOrigin := map[model.ID][]*microflows.SequenceFlow{
+		mkID("start"): {mkFlow("start", "init")},
+		mkID("init"):  {mkFlow("init", "outer_split")},
+		mkID("outer_split"): {
+			mkBranchFlow("outer_split", "before_type_split", &microflows.ExpressionCase{Expression: "true"}),
+			mkBranchFlow("outer_split", "outer_merge", &microflows.ExpressionCase{Expression: "false"}),
+		},
+		mkID("before_type_split"): {mkFlow("before_type_split", "type_split")},
+		mkID("type_split"): {
+			mkBranchFlow("type_split", "set_token", &microflows.InheritanceCase{EntityID: entityID}),
+			mkBranchFlow("type_split", "failed_log", &microflows.InheritanceCase{}),
+		},
+		mkID("set_token"):   {mkFlow("set_token", "outer_merge")},
+		mkID("failed_log"):  {mkFlow("failed_log", "failed_return")},
+		mkID("outer_merge"): {mkFlow("outer_merge", "tail")},
+		mkID("tail"):        {mkFlow("tail", "end")},
+	}
+	splitMergeMap := map[model.ID]model.ID{mkID("outer_split"): mkID("outer_merge")}
+	entityNames := map[model.ID]string{entityID: "Sample.SpecializedInput"}
+
+	var lines []string
+	visited := make(map[model.ID]bool)
+	e.traverseFlow(mkID("start"), activityMap, flowsByOrigin, splitMergeMap, visited, entityNames, nil, &lines, 0, nil, 0, nil)
+
+	out := strings.Join(lines, "\n")
+	tail := strings.Index(out, "tail after split")
+	endSplit := strings.Index(out, "end split;")
+	endIf := strings.Index(out, "end if;")
+	if tail == -1 {
+		t.Fatalf("expected parent tail after nested inheritance split:\n%s", out)
+	}
+	if endSplit == -1 || tail < endSplit {
+		t.Fatalf("parent tail must not be emitted inside the inheritance case:\n%s", out)
+	}
+	if endIf == -1 || tail < endIf {
+		t.Fatalf("parent tail must remain after the outer IF closes:\n%s", out)
+	}
+}
+
 func TestLastStmtIsReturn_InheritanceSplitAllBranchesReturn(t *testing.T) {
 	body := []ast.MicroflowStatement{
 		&ast.InheritanceSplitStmt{

mdl/executor/cmd_microflows_show_helpers.go

@@ -806,7 +806,7 @@ func traverseFlowUntilMerge(
 		startLine := len(*lines) + headerLineCount
 		nestedMergeID := splitMergeMap[currentID]
 		emitObjectAnnotations(obj, lines, indentStr, annotationsByTarget, flowsByOrigin, flowsByDest, activityMap)
-		emitInheritanceSplitStatement(ctx, currentID, nestedMergeID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, visited, entityNames, microflowNames, lines, indent, sourceMap, headerLineCount, annotationsByTarget)
+		emitInheritanceSplitStatement(ctx, currentID, mergeID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, visited, entityNames, microflowNames, lines, indent, sourceMap, headerLineCount, annotationsByTarget)
 		recordSourceMap(sourceMap, currentID, startLine, len(*lines)+headerLineCount-1)
 		if nestedMergeID != "" && nestedMergeID != mergeID {
 			visited[nestedMergeID] = true
@@ -1276,7 +1276,7 @@ func emitEnumSplitStatement(
 func emitInheritanceSplitStatement(
 	ctx *ExecContext,
 	currentID model.ID,
-	mergeID model.ID,
+	stopID model.ID,
 	activityMap map[model.ID]microflows.MicroflowObject,
 	flowsByOrigin map[model.ID][]*microflows.SequenceFlow,
 	flowsByDest map[model.ID][]*microflows.SequenceFlow,
@@ -1301,6 +1301,11 @@ func emitInheritanceSplitStatement(
 	indentStr := strings.Repeat("  ", indent)
 	*lines = append(*lines, indentStr+"split type "+varName)
 
+	branchStopID := splitMergeMap[currentID]
+	if branchStopID == "" {
+		branchStopID = stopID
+	}
+
 	var elseFlow *microflows.SequenceFlow
 	for _, flow := range orderedInheritanceSplitFlows(findNormalFlows(flowsByOrigin[currentID])) {
 		caseName, ok := inheritanceCaseName(flow, entityNames)
@@ -1309,11 +1314,11 @@ func emitInheritanceSplitStatement(
 			continue
 		}
 		*lines = append(*lines, indentStr+"case "+caseName)
-		traverseFlowUntilMerge(ctx, flow.DestinationID, mergeID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, cloneVisited(visited), entityNames, microflowNames, lines, indent+1, sourceMap, headerLineCount, annotationsByTarget)
+		traverseFlowUntilMerge(ctx, flow.DestinationID, branchStopID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, cloneVisited(visited), entityNames, microflowNames, lines, indent+1, sourceMap, headerLineCount, annotationsByTarget)
 	}
 	if elseFlow != nil {
 		*lines = append(*lines, indentStr+"else")
-		traverseFlowUntilMerge(ctx, elseFlow.DestinationID, mergeID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, cloneVisited(visited), entityNames, microflowNames, lines, indent+1, sourceMap, headerLineCount, annotationsByTarget)
+		traverseFlowUntilMerge(ctx, elseFlow.DestinationID, branchStopID, activityMap, flowsByOrigin, flowsByDest, splitMergeMap, cloneVisited(visited), entityNames, microflowNames, lines, indent+1, sourceMap, headerLineCount, annotationsByTarget)
 	}
 	*lines = append(*lines, indentStr+"end split;")
 }