fix(srv6): don't wedge EgressPolicy in Terminating on un-encodable withdraw

srv6egress/cmd/bgp-controller/main.go

@@ -98,6 +98,16 @@ func main() {
 	var encoder bgp.Encoder
 	switch bgpEncoding {
 	case "sr-policy":
+		// The headend keys its SR Policy install on the BSID, so under this
+		// encoding every color needs one. Fail fast at load instead of letting
+		// a bsid-less color go non-Ready yet un-deletable (BuildPath would fail
+		// on both Announce and Withdraw).
+		for color, cc := range cfg.Colors {
+			if cc.BSID == "" {
+				log.Error(fmt.Errorf("color %d: bsid is required with --bgp-encoding=sr-policy", color), "invalid config")
+				os.Exit(1)
+			}
+		}
 		encoder = bgp.NewSRPolicyEncoder(bgp.SRPolicyOptions{})
 	case "color-route":
 		encoder = bgp.NewColoredEncoder()

srv6egress/internal/controller/egresspolicy_controller.go

@@ -226,7 +226,15 @@ func (r *EgressPolicyReconciler) reconcileDelete(ctx context.Context, ep *srv6eg
 			EndpointAddr: sp.EndpointAddr,
 			BSID:         sp.BSID,
 		}
-		if err := r.BGP.Withdraw(ctx, owner, r.Encoder.ClusterAdvert(key, sp.SegmentList)); err != nil {
+		adv := r.Encoder.ClusterAdvert(key, sp.SegmentList)
+		if _, err := adv.BuildPath(); err != nil {
+			// Deterministic encode failure (e.g. sr-policy with an empty
+			// BSID/endpoint): nothing valid could have been announced, so there
+			// is nothing to withdraw. Log and drop the finalizer rather than
+			// wedging the object in Terminating forever on every reconcile.
+			log.Error(err, "cannot rebuild withdraw advert; dropping finalizer without withdraw", "name", ep.Name)
+		} else if err := r.BGP.Withdraw(ctx, owner, adv); err != nil {
+			// Transient transport error: keep the finalizer and retry.
 			return ctrl.Result{}, err
 		}
 	}