fix: track add-to-list expression inputs

Symptom: expression-valued add-to-list statements were parsed and written correctly, but validator and builder graph walkers only inspected the legacy Item field.

Root cause: the new Value expression path was not wired into referenced-variable and object-input collection, so variables used only inside add expressions could be missed.

Fix: walk AddToListStmt.Value when present, keep the legacy Item fallback for synthetic callers, and rename the doctype example to .mdl so CI executes it.

Tests: added builder, validator, and visitor assertions; ran mxcli check for the doctype fixture plus make build and make test.

Author: hjothamendix

…pe-tests/add_expression_to_list.test.mdl …doctype-tests/add_expression_to_list.mdlmdl-examples/doctype-tests/add_expression_to_list.test.mdl renamed to mdl-examples/doctype-tests/add_expression_to_list.mdl mdl-examples/doctype-tests/add_expression_to_list.test.mdl renamed to mdl-examples/doctype-tests/add_expression_to_list.mdl

@@ -40,6 +40,24 @@ func TestAddToListBuilderKeepsSimpleVariableFallback(t *testing.T) {
 	}
 }
 
+func TestCollectObjectInputVariablesSeesAddExpressionValue(t *testing.T) {
+	inputs := collectObjectInputVariables([]ast.MicroflowStatement{
+		&ast.AddToListStmt{
+			Value: &ast.FunctionCallExpr{
+				Name: "head",
+				Arguments: []ast.Expression{
+					&ast.VariableExpr{Name: "SourceItems"},
+				},
+			},
+			List: "Items",
+		},
+	})
+
+	if !inputs["SourceItems"] {
+		t.Fatalf("SourceItems was not collected from add expression: %#v", inputs)
+	}
+}
+
 func lastChangeListAction(t *testing.T, fb *flowBuilder) *microflows.ChangeListAction {
 	t.Helper()
 

mdl/executor/cmd_microflows_builder_add_to_list_test.go

@@ -309,7 +309,11 @@ func collectObjectInputVariables(stmts []ast.MicroflowStatement) map[string]bool
 			case *ast.AggregateListStmt:
 				walkExpr(s.Expression)
 			case *ast.AddToListStmt:
-				if s.Item != "" {
+				if s.Value != nil {
+					for _, ref := range exprVarRefs(s.Value) {
+						inputs[ref] = true
+					}
+				} else if s.Item != "" {
 					inputs[s.Item] = true
 				}
 			case *ast.CallMicroflowStmt:

mdl/executor/cmd_microflows_builder_graph.go

@@ -481,7 +481,12 @@ func referencedVars(stmt ast.MicroflowStatement) []string {
 	case *ast.DeleteObjectStmt:
 		refs = append(refs, s.Variable)
 	case *ast.AddToListStmt:
-		refs = append(refs, s.Item, s.List)
+		if s.Value != nil {
+			refs = append(refs, exprVarRefs(s.Value)...)
+		} else {
+			refs = append(refs, s.Item)
+		}
+		refs = append(refs, s.List)
 	case *ast.RemoveFromListStmt:
 		refs = append(refs, s.Item, s.List)
 	case *ast.LogStmt:

mdl/executor/validate_microflow.go

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package executor
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/mendixlabs/mxcli/mdl/ast"
+	"github.com/mendixlabs/mxcli/mdl/visitor"
+)
+
+func TestValidateMicroflowReferencesAddExpressionValue(t *testing.T) {
+	input := `create microflow Synthetic.MF_AddExpressionScope ()
+returns Boolean
+begin
+  declare $Items List of Synthetic.Item = empty;
+  if true then
+    declare $SourceItems List of Synthetic.Item = empty;
+  end if;
+  add head($SourceItems) to $Items;
+  return true;
+end;`
+
+	prog, errs := visitor.Build(input)
+	if len(errs) > 0 {
+		t.Fatalf("Parse error: %v", errs[0])
+	}
+	stmt := prog.Statements[0].(*ast.CreateMicroflowStmt)
+
+	violations := ValidateMicroflow(stmt)
+	for _, violation := range violations {
+		if violation.RuleID == "MDL005" && strings.Contains(violation.Message, "$SourceItems") {
+			return
+		}
+	}
+	t.Fatalf("Expected MDL005 for add expression source variable, got %#v", violations)
+}

mdl/executor/validate_microflow_add_to_list_test.go

@@ -67,4 +67,11 @@ END;`
 	if addStmt.Item != "Order" {
 		t.Fatalf("Item = %q, want Order", addStmt.Item)
 	}
+	varExpr, ok := addStmt.Value.(*ast.VariableExpr)
+	if !ok {
+		t.Fatalf("Value = %T, want VariableExpr", addStmt.Value)
+	}
+	if varExpr.Name != "Order" {
+		t.Fatalf("Value.Name = %q, want Order", varExpr.Name)
+	}
 }