fix(tax-code): fix tax code delete

api/v3/handlers/taxcodes/delete.go

@@ -18,8 +18,6 @@ type (
 	DeleteTaxCodeHandler  = httptransport.HandlerWithArgs[DeleteTaxCodeRequest, DeleteTaxCodeResponse, DeleteTaxCodeParams]
 )
 
-const deleteTaxCodeEnabled = false
-
 // DeleteTaxCode returns a handler for deleting a tax code.
 func (h *handler) DeleteTaxCode() DeleteTaxCodeHandler {
 	return httptransport.NewHandlerWithArgs(
@@ -37,10 +35,6 @@ func (h *handler) DeleteTaxCode() DeleteTaxCodeHandler {
 			}, nil
 		},
 		func(ctx context.Context, request DeleteTaxCodeRequest) (DeleteTaxCodeResponse, error) {
-			if !deleteTaxCodeEnabled {
-				return nil, apierrors.NewForbiddenErrorDetail(ctx, "deleting tax codes is not allowed")
-			}
-
 			err := h.service.DeleteTaxCode(ctx, taxcode.DeleteTaxCodeInput{
 				NamespacedID: models.NamespacedID{
 					Namespace: request.Namespace,

app/common/productcatalog.go

@@ -25,6 +25,7 @@ import (
 	"github.com/openmeterio/openmeter/openmeter/productcatalog/planaddon"
 	planaddonadapter "github.com/openmeterio/openmeter/openmeter/productcatalog/planaddon/adapter"
 	planaddonservice "github.com/openmeterio/openmeter/openmeter/productcatalog/planaddon/service"
+	"github.com/openmeterio/openmeter/openmeter/productcatalog/taxcoderesolver"
 	"github.com/openmeterio/openmeter/openmeter/streaming"
 	"github.com/openmeterio/openmeter/openmeter/taxcode"
 	"github.com/openmeterio/openmeter/openmeter/watermill/eventbus"
@@ -49,6 +50,7 @@ var Cost = wire.NewSet(
 
 var Plan = wire.NewSet(
 	NewPlanService,
+	NewTaxCodeResolver,
 )
 
 var Addon = wire.NewSet(
@@ -71,6 +73,8 @@ func NewFeatureConnector(
 
 var NewFeatureResolver = featureresolver.New
 
+var NewTaxCodeResolver = taxcoderesolver.New
+
 func NewCostService(
 	featureConnector feature.FeatureConnector,
 	meterService meter.Service,
@@ -88,6 +92,7 @@ func NewPlanService(
 	logger *slog.Logger,
 	db *entdb.Client,
 	featureResolver productcatalog.FeatureResolver,
+	taxCodeResolver productcatalog.TaxCodeResolver,
 	taxCodeService taxcode.Service,
 	publisher eventbus.Publisher,
 ) (plan.Service, error) {
@@ -102,6 +107,7 @@ func NewPlanService(
 	return planservice.New(planservice.Config{
 		Adapter:         adapter,
 		FeatureResolver: featureResolver,
+		TaxCodeResolver: taxCodeResolver,
 		TaxCode:         taxCodeService,
 		Logger:          logger.With("subsystem", "productcatalog.plan"),
 		Publisher:       publisher,

app/common/taxcode.go

@@ -1,6 +1,7 @@
 package common
 
 import (
+	"fmt"
 	"log/slog"
 	"strings"
 
@@ -10,9 +11,11 @@ import (
 	"github.com/openmeterio/openmeter/app/config"
 	"github.com/openmeterio/openmeter/openmeter/app"
 	entdb "github.com/openmeterio/openmeter/openmeter/ent/db"
+	"github.com/openmeterio/openmeter/openmeter/productcatalog/plan"
 	"github.com/openmeterio/openmeter/openmeter/taxcode"
 	taxcodeadapter "github.com/openmeterio/openmeter/openmeter/taxcode/adapter"
 	taxcodeservice "github.com/openmeterio/openmeter/openmeter/taxcode/service"
+	taxcodehooks "github.com/openmeterio/openmeter/openmeter/taxcode/service/hooks"
 )
 
 var TaxCode = wire.NewSet(
@@ -42,6 +45,28 @@ func NewTaxCodeService(
 	})
 }
 
+// TaxCodePlanHook prevents deleting tax codes that are still referenced by plans.
+type TaxCodePlanHook taxcodehooks.PlanHook
+
+// NewTaxCodePlanServiceHook builds the plan-reference hook and registers it
+// on the tax code service. It depends on both the plan and tax code services so wire constructs
+// it only after both exist, avoiding a construction cycle (plan already depends on tax code).
+func NewTaxCodePlanServiceHook(
+	planService plan.Service,
+	taxCodeService taxcode.Service,
+) (TaxCodePlanHook, error) {
+	h, err := taxcodehooks.NewPlanHook(taxcodehooks.PlanHookConfig{
+		PlanService: planService,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create tax code plan hook: %w", err)
+	}
+
+	taxCodeService.RegisterHooks(h)
+
+	return h, nil
+}
+
 func NewTaxCodeNamespaceHandler(
 	logger *slog.Logger,
 	service taxcode.Service,

cmd/server/wire.go

@@ -99,6 +99,7 @@ type Application struct {
 	StreamingConnector               streaming.Connector
 	TaxCodeNamespaceHandler          *taxcode.NamespaceHandler
 	TaxCodeService                   taxcode.Service
+	TaxCodePlanHook                  common.TaxCodePlanHook
 	TelemetryServer                  common.TelemetryServer
 	TerminationChecker               *common.TerminationChecker
 	RuntimeMetricsCollector          common.RuntimeMetricsCollector
@@ -148,6 +149,7 @@ func initializeApplication(ctx context.Context, conf config.Configuration) (Appl
 		common.Server,
 		common.TaxCode,
 		common.TaxCodeNamespaceHandler,
+		common.NewTaxCodePlanServiceHook,
 		common.Subscription,
 		common.Lockr,
 		common.Secret,

openmeter/billing/service/invoiceupdate_test.go

@@ -1000,6 +1000,8 @@ func (s *invoiceUpdateTaxCodeService) UpsertOrganizationDefaultTaxCodes(context.
 	return taxcode.OrganizationDefaultTaxCodes{}, errors.New("UpsertOrganizationDefaultTaxCodes is not supported in this test")
 }
 
+func (s *invoiceUpdateTaxCodeService) RegisterHooks(...models.ServiceHook[taxcode.TaxCode]) {}
+
 type preallocatingInvoiceLineAdapter struct {
 	billing.Adapter
 }

openmeter/productcatalog/errors.go

@@ -121,6 +121,16 @@ var ErrRateCardFeatureArchived = models.NewValidationIssue(
 	commonhttp.WithHTTPStatusCodeAttribute(http.StatusBadRequest),
 )
 
+const ErrCodeRateCardTaxCodeNotFound models.ErrorCode = "rate_card_tax_code_not_found"
+
+var ErrRateCardTaxCodeNotFound = models.NewValidationIssue(
+	ErrCodeRateCardTaxCodeNotFound,
+	"tax code not found",
+	models.WithFieldString("taxConfig"),
+	models.WithCriticalSeverity(),
+	commonhttp.WithHTTPStatusCodeAttribute(http.StatusBadRequest),
+)
+
 const ErrCodeRateCardFeatureMismatch models.ErrorCode = "rate_card_feature_mismatch"
 
 var ErrRateCardFeatureMismatch = models.NewValidationIssue(

openmeter/productcatalog/plan.go

@@ -365,3 +365,24 @@ func ValidatePlanWithFeatures(ctx context.Context, resolver NamespacedFeatureRes
 		return errors.Join(errs...)
 	}
 }
+
+func ValidatePlanWithTaxCodes(ctx context.Context, resolver NamespacedTaxCodeResolver) models.ValidatorFunc[Plan] {
+	return func(p Plan) error {
+		var errs []error
+
+		for _, phase := range p.Phases {
+			phaseFieldSelector := models.NewFieldSelectorGroup(
+				models.NewFieldSelector("phases").
+					WithExpression(
+						models.NewFieldAttrValue("key", phase.Key),
+					),
+			)
+
+			if err := ValidateRateCardsWithTaxCodes(ctx, resolver)(phase.RateCards); err != nil {
+				errs = append(errs, models.ErrorWithFieldPrefix(phaseFieldSelector, err))
+			}
+		}
+
+		return errors.Join(errs...)
+	}
+}