fix: address PR #224 review feedback

- Include qualified name in AlreadyExists error messages (cmd_dbconnection, cmd_enumerations)
- Preserve hint text in NotConnected error for SHOW FEATURES (cmd_features)
- Use typed ValidationError for statement timeout (executor.go)
- Standardize RawUnitBackend.GetRawUnitBytes to use model.ID (infrastructure.go, mpr/backend, mock/backend)
- Fix panic message prefix from 'backend:' to 'registry:' (registry.go)
- Add NewNotConnectedMsg constructor (errors.go)

Author: retran

mdl/backend/infrastructure.go

@@ -19,7 +19,7 @@ type RenameBackend interface {
 // manipulate raw BSON (e.g. widget patching, alter page/workflow).
 type RawUnitBackend interface {
 	GetRawUnit(id model.ID) (map[string]any, error)
-	GetRawUnitBytes(id string) ([]byte, error)
+	GetRawUnitBytes(id model.ID) ([]byte, error)
 	ListRawUnitsByType(typePrefix string) ([]*mpr.RawUnit, error)
 	ListRawUnits(objectType string) ([]*mpr.RawUnitInfo, error)
 	GetRawUnitByName(objectType, qualifiedName string) (*mpr.RawUnitInfo, error)

mdl/backend/mock/backend.go

@@ -238,7 +238,7 @@ type MockBackend struct {
 
 	// RawUnitBackend
 	GetRawUnitFunc            func(id model.ID) (map[string]any, error)
-	GetRawUnitBytesFunc       func(id string) ([]byte, error)
+	GetRawUnitBytesFunc       func(id model.ID) ([]byte, error)
 	ListRawUnitsByTypeFunc    func(typePrefix string) ([]*mpr.RawUnit, error)
 	ListRawUnitsFunc          func(objectType string) ([]*mpr.RawUnitInfo, error)
 	GetRawUnitByNameFunc      func(objectType, qualifiedName string) (*mpr.RawUnitInfo, error)
@@ -1574,7 +1574,7 @@ func (m *MockBackend) GetRawUnit(id model.ID) (map[string]any, error) {
 	return nil, nil
 }
 
-func (m *MockBackend) GetRawUnitBytes(id string) ([]byte, error) {
+func (m *MockBackend) GetRawUnitBytes(id model.ID) ([]byte, error) {
 	if m.GetRawUnitBytesFunc != nil {
 		return m.GetRawUnitBytesFunc(id)
 	}

mdl/backend/mpr/backend.go

@@ -627,8 +627,8 @@ func (b *MprBackend) RenameDocumentByName(moduleName, oldName, newName string) e
 func (b *MprBackend) GetRawUnit(id model.ID) (map[string]any, error) {
 	return b.reader.GetRawUnit(id)
 }
-func (b *MprBackend) GetRawUnitBytes(id string) ([]byte, error) {
-	return b.reader.GetRawUnitBytes(model.ID(id))
+func (b *MprBackend) GetRawUnitBytes(id model.ID) ([]byte, error) {
+	return b.reader.GetRawUnitBytes(id)
 }
 func (b *MprBackend) ListRawUnitsByType(typePrefix string) ([]*mpr.RawUnit, error) {
 	return b.reader.ListRawUnitsByType(typePrefix)

mdl/errors/errors.go

@@ -33,6 +33,11 @@ func NewNotConnected() *NotConnectedError {
 	return &NotConnectedError{msg: "not connected to a project"}
 }
 
+// NewNotConnectedMsg creates a NotConnectedError with a custom message.
+func NewNotConnectedMsg(msg string) *NotConnectedError {
+	return &NotConnectedError{msg: msg}
+}
+
 // NewNotConnectedWrite creates a NotConnectedError for write access.
 func NewNotConnectedWrite() *NotConnectedError {
 	return &NotConnectedError{WriteMode: true, msg: "not connected to a project in write mode"}

mdl/executor/cmd_dbconnection.go

@@ -40,7 +40,7 @@ func (e *Executor) createDatabaseConnection(stmt *ast.CreateDatabaseConnectionSt
 					return mdlerrors.NewBackend("delete existing connection", err)
 				}
 			} else {
-				return mdlerrors.NewAlreadyExistsMsg("database connection", modName+"."+ex.Name, "use CREATE OR MODIFY to update")
+				return mdlerrors.NewAlreadyExistsMsg("database connection", modName+"."+ex.Name, fmt.Sprintf("database connection already exists: %s.%s (use CREATE OR MODIFY to update)", modName, ex.Name))
 			}
 		}
 	}

mdl/executor/cmd_enumerations.go

@@ -39,7 +39,7 @@ func (e *Executor) execCreateEnumeration(s *ast.CreateEnumerationStmt) error {
 	// Check if enumeration already exists
 	existingEnum := e.findEnumeration(s.Name.Module, s.Name.Name)
 	if existingEnum != nil && !s.CreateOrModify {
-		return mdlerrors.NewAlreadyExistsMsg("enumeration", s.Name.Module+"."+s.Name.Name, "use CREATE OR MODIFY to update")
+		return mdlerrors.NewAlreadyExistsMsg("enumeration", s.Name.Module+"."+s.Name.Name, fmt.Sprintf("enumeration already exists: %s.%s (use CREATE OR MODIFY to update)", s.Name.Module, s.Name.Name))
 	}
 
 	// Create enumeration values

mdl/executor/cmd_features.go

@@ -75,7 +75,7 @@ func (e *Executor) execShowFeatures(s *ast.ShowFeaturesStmt) error {
 	default:
 		// SHOW FEATURES [IN area] — requires project connection
 		if e.reader == nil {
-			return mdlerrors.NewNotConnected()
+			return mdlerrors.NewNotConnectedMsg("not connected to a project\n  hint: use SHOW FEATURES FOR VERSION x.y without a project connection")
 		}
 		rpv := e.reader.ProjectVersion()
 		pv = versions.SemVer{Major: rpv.MajorVersion, Minor: rpv.MinorVersion, Patch: rpv.PatchVersion}

mdl/executor/executor.go

@@ -207,7 +207,7 @@ func (e *Executor) Execute(stmt ast.Statement) error {
 	case r := <-ch:
 		err = r.err
 	case <-ctx.Done():
-		err = fmt.Errorf("statement timed out after %v", executeTimeout)
+		err = mdlerrors.NewValidationf("statement timed out after %v", executeTimeout)
 	}
 
 	if e.logger != nil {

mdl/executor/registry.go

@@ -63,7 +63,7 @@ func NewRegistry() *Registry {
 func (r *Registry) Register(stmt ast.Statement, handler StmtHandler) {
 	t := reflect.TypeOf(stmt)
 	if _, exists := r.handlers[t]; exists {
-		panic(fmt.Sprintf("backend: duplicate handler registration for %s", t))
+		panic(fmt.Sprintf("registry: duplicate handler registration for %s", t))
 	}
 	r.handlers[t] = handler
 }