fix: handle legacy alert type values on patch

pkg/query-service/rules/manager.go

@@ -952,6 +952,7 @@ func (m *Manager) PatchRule(ctx context.Context, ruleStr string, id valuer.UUID)
 		m.logger.ErrorContext(ctx, "failed to unmarshal rule from db", slog.String("rule.id", id.StringValue()), errors.Attr(err))
 		return nil, err
 	}
+	storedRule.NormalizeAlertType()
 
 	if err := json.Unmarshal([]byte(ruleStr), &storedRule); err != nil {
 		m.logger.ErrorContext(ctx, "failed to unmarshal patched rule with given id", slog.String("rule.id", id.StringValue()), errors.Attr(err))

pkg/types/ruletypes/api_params.go

@@ -36,6 +36,15 @@ func (AlertType) Enum() []any {
 	}
 }
 
+// NormalizeAlertType corrects known legacy alert type values that were stored
+// before strict validation was introduced. The corrected value is persisted on
+// the next write, so the DB self-heals without a migration.
+func (r *PostableRule) NormalizeAlertType() {
+	if r.AlertType == "LOG_BASED_ALERT" {
+		r.AlertType = AlertTypeLogs
+	}
+}
+
 const (
 	DefaultSchemaVersion  = "v1"
 	SchemaVersionV2Alpha1 = "v2alpha1"