fix: infer java action result variable types

mdl-examples/bug-tests/352-java-action-return-type-inference.mdl

@@ -0,0 +1,56 @@
+-- ============================================================================
+-- Bug #352 (part): Java action result variable type inference
+-- ============================================================================
+--
+-- Symptom (before fix):
+--   The microflow builder looked up Java action definitions to format
+--   entity-typed parameters, but it did NOT register the Java action's
+--   return type on the output variable. Subsequent statements that
+--   touched the result (`change`, `commit`, `$Result/Attribute`,
+--   association paths) had no type info, so:
+--     - the writer fell back to untyped expressions
+--     - `mx check` could surface CE0117 on dependent activities
+--     - describe re-emitted the call without the right variable
+--       declaration shape
+--
+-- After fix:
+--   `addCallJavaActionAction` consults the Java action's `ReturnType`
+--   and registers the output variable as the appropriate object/list
+--   type (`Module.Entity`, `List of Module.Entity`, `System.FileDocument`,
+--   etc.) so downstream activities resolve correctly.
+--
+-- Usage:
+--   mxcli exec mdl-examples/bug-tests/352-java-action-return-type-inference.mdl -p app.mpr
+--   mxcli -p app.mpr -c "describe microflow BugTest352b.MF_UseJavaResult"
+--   `mx check` against the resulting MPR must report 0 errors.
+-- ============================================================================
+
+create module BugTest352b;
+
+create persistent entity BugTest352b.LogEntry (
+  Message : string(500)
+);
+/
+
+-- Java action returning an entity object — the result variable type must
+-- be inferred so downstream `change` / `commit` resolve.
+create java action BugTest352b.CreateLogEntry (
+  Msg: string not null
+) returns BugTest352b.LogEntry
+as $$
+return new com.mendix.systemwideinterfaces.core.IMendixObject();
+$$;
+/
+
+-- Caller microflow that depends on the inferred return type. The change
+-- statement on `$Entry/Message` would fail validation if the Java action
+-- result variable type is not registered.
+create microflow BugTest352b.MF_UseJavaResult (
+  $Msg: string
+)
+returns BugTest352b.LogEntry as $Entry
+begin
+  $Entry = call java action BugTest352b.CreateLogEntry (Msg = $Msg);
+  change $Entry (Message = $Msg + ' (processed)');
+end;
+/

mdl/executor/cmd_microflows_builder_calls.go

@@ -241,6 +241,13 @@ func (fb *flowBuilder) addCallJavaActionAction(s *ast.CallJavaActionStmt) model.
 		ResultVariableName: s.OutputVariable,
 		UseReturnVariable:  s.OutputVariable != "",
 	}
+	if s.OutputVariable != "" && jaDef != nil && fb.varTypes != nil {
+		if varType := javaActionReturnVarType(jaDef.ReturnType); varType != "" {
+			fb.varTypes[s.OutputVariable] = varType
+		} else if inferred := fb.inferGenericJavaActionReturnType(jaDef, s); inferred != "" {
+			fb.varTypes[s.OutputVariable] = inferred
+		}
+	}
 
 	activityX := fb.posX
 	activity := &microflows.ActionActivity{
@@ -268,6 +275,48 @@ func (fb *flowBuilder) addCallJavaActionAction(s *ast.CallJavaActionStmt) model.
 	return activity.ID
 }
 
+func javaActionReturnVarType(returnType javaactions.CodeActionReturnType) string {
+	switch t := returnType.(type) {
+	case *javaactions.EntityType:
+		return t.Entity
+	case *javaactions.ListType:
+		if t.Entity != "" {
+			return "List of " + t.Entity
+		}
+	case *javaactions.FileDocumentType:
+		return "System.FileDocument"
+	}
+	return ""
+}
+
+func (fb *flowBuilder) inferGenericJavaActionReturnType(jaDef *javaactions.JavaAction, s *ast.CallJavaActionStmt) string {
+	if jaDef == nil || fb.varTypes == nil || s == nil {
+		return ""
+	}
+	switch t := jaDef.ReturnType.(type) {
+	case *javaactions.ListType:
+		if t.Entity != "" {
+			return ""
+		}
+	case javaactions.ListType:
+		if t.Entity != "" {
+			return ""
+		}
+	default:
+		return ""
+	}
+	for _, arg := range s.Arguments {
+		valueExpr := strings.TrimPrefix(strings.Trim(fb.exprToString(arg.Value), "'"), "$")
+		if valueExpr == "" {
+			continue
+		}
+		if typ := fb.varTypes[valueExpr]; strings.HasPrefix(typ, "List of ") {
+			return typ
+		}
+	}
+	return ""
+}
+
 // addCallExternalActionAction creates a CALL EXTERNAL ACTION statement.
 func (fb *flowBuilder) addCallExternalActionAction(s *ast.CallExternalActionStmt) model.ID {
 	serviceQN := s.ServiceName.Module + "." + s.ServiceName.Name

mdl/executor/cmd_microflows_builder_java_return_test.go

@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package executor
+
+import (
+	"testing"
+
+	"github.com/mendixlabs/mxcli/mdl/ast"
+	"github.com/mendixlabs/mxcli/mdl/backend/mock"
+	"github.com/mendixlabs/mxcli/sdk/javaactions"
+)
+
+func TestAddJavaAction_FileDocumentReturnRegistersSystemFileDocument(t *testing.T) {
+	backend := &mock.MockBackend{
+		ReadJavaActionByNameFunc: func(qualifiedName string) (*javaactions.JavaAction, error) {
+			if qualifiedName != "Spreadsheet.ExportRows" {
+				return nil, nil
+			}
+			return &javaactions.JavaAction{
+				ReturnType: &javaactions.FileDocumentType{},
+			}, nil
+		},
+	}
+
+	fb := &flowBuilder{
+		backend:      backend,
+		varTypes:     map[string]string{},
+		declaredVars: map[string]string{},
+	}
+
+	fb.addCallJavaActionAction(&ast.CallJavaActionStmt{
+		OutputVariable: "GeneratedDocument",
+		ActionName:     ast.QualifiedName{Module: "Spreadsheet", Name: "ExportRows"},
+	})
+
+	if got := fb.varTypes["GeneratedDocument"]; got != "System.FileDocument" {
+		t.Fatalf("GeneratedDocument type = %q, want System.FileDocument", got)
+	}
+}
+
+func TestAddJavaAction_ConcreteListReturnRegistersListType(t *testing.T) {
+	backend := &mock.MockBackend{
+		ReadJavaActionByNameFunc: func(qualifiedName string) (*javaactions.JavaAction, error) {
+			return &javaactions.JavaAction{
+				ReturnType: &javaactions.ListType{Entity: "Orders.Order"},
+			}, nil
+		},
+	}
+
+	fb := &flowBuilder{
+		backend:      backend,
+		varTypes:     map[string]string{},
+		declaredVars: map[string]string{},
+	}
+
+	fb.addCallJavaActionAction(&ast.CallJavaActionStmt{
+		OutputVariable: "FilteredOrders",
+		ActionName:     ast.QualifiedName{Module: "Lists", Name: "FilterOrders"},
+	})
+
+	if got := fb.varTypes["FilteredOrders"]; got != "List of Orders.Order" {
+		t.Fatalf("FilteredOrders type = %q, want list type", got)
+	}
+}
+
+func TestAddJavaAction_GenericListReturnInheritsInputListType(t *testing.T) {
+	backend := &mock.MockBackend{
+		ReadJavaActionByNameFunc: func(qualifiedName string) (*javaactions.JavaAction, error) {
+			return &javaactions.JavaAction{
+				ReturnType: &javaactions.ListType{},
+			}, nil
+		},
+	}
+
+	fb := &flowBuilder{
+		varTypes: map[string]string{
+			"InputOrders": "List of Orders.Order",
+		},
+		declaredVars: map[string]string{},
+		backend:      backend,
+		measurer:     &layoutMeasurer{},
+	}
+
+	fb.addCallJavaActionAction(&ast.CallJavaActionStmt{
+		OutputVariable: "FilteredOrders",
+		ActionName:     ast.QualifiedName{Module: "Lists", Name: "FilterGeneric"},
+		Arguments: []ast.CallArgument{
+			{Name: "InputList", Value: &ast.VariableExpr{Name: "InputOrders"}},
+		},
+	})
+
+	if got := fb.varTypes["FilteredOrders"]; got != "List of Orders.Order" {
+		t.Fatalf("generic java list result type = %q, want input list type", got)
+	}
+}