fix: skip empty node name in local snapshot info after pause finalization

cmd/ateapi/internal/controlapi/workflow_pause.go

@@ -157,8 +157,11 @@ type FinalizePausedStep struct {
 
 func (s *FinalizePausedStep) Name() string { return "FinalizePaused" }
 func (s *FinalizePausedStep) IsComplete(ctx context.Context, input *PauseInput, state *PauseState) (bool, error) {
-	// The workflow is completely done ONLY if the status is PAUSED *and* we've successfully freed the worker.
-	return state.Actor.GetStatus() == ateapipb.Actor_STATUS_PAUSED && state.Actor.GetAteomPodNamespace() == "", nil
+	// The workflow is done once the worker is freed and the actor reached PAUSED,
+	// or CRASHED (node name was lost, so it can never be safely resumed).
+	status := state.Actor.GetStatus()
+	terminal := status == ateapipb.Actor_STATUS_PAUSED || status == ateapipb.Actor_STATUS_CRASHED
+	return terminal && state.Actor.GetAteomPodNamespace() == "", nil
 }
 func (s *FinalizePausedStep) Execute(ctx context.Context, input *PauseInput, state *PauseState) error {
 	latestActor, err := s.store.GetActor(ctx, input.Atespace, input.ActorName)
@@ -202,19 +205,24 @@ func (s *FinalizePausedStep) Execute(ctx context.Context, input *PauseInput, sta
 			return err
 		}
 		latestActor.Status = ateapipb.Actor_STATUS_PAUSED
-		// TODO(dberkov) - what if we still don't know the node name? Maybe move to CRASHED status?
 		if nodeName == "" {
-			slog.Warn("Node name not found during finalize pause", "actor", input.ActorName)
+			// Without a node name we cannot record where the local snapshot lives,
+			// so the actor can never be resumed (findFreeWorker would search for a
+			// worker on an unknown node forever). Crash it instead of leaving it
+			// stuck in PAUSED.
+			slog.ErrorContext(ctx, "Node name not found during finalize pause, crashing actor", "actor", input.ActorName)
+			latestActor.Status = ateapipb.Actor_STATUS_CRASHED
 		}
 		// TODO(dberkov) - what if InProgressSnapshot is empty? That shouldn't be possible.
 		if latestActor.InProgressSnapshot != "" {
+			localInfo := &ateapipb.LocalSnapshotInfo{
+				SnapshotPrefix: latestActor.InProgressSnapshot,
+			}
+			if latestActor.Status != ateapipb.Actor_STATUS_CRASHED {
+				localInfo.NodeVmsWithLocalSnapshots = []string{nodeName}
+			}
 			latestActor.LatestSnapshotInfo = &ateapipb.SnapshotInfo{
-				Data: &ateapipb.SnapshotInfo_Local{
-					Local: &ateapipb.LocalSnapshotInfo{
-						SnapshotPrefix:            latestActor.InProgressSnapshot,
-						NodeVmsWithLocalSnapshots: []string{nodeName},
-					},
-				},
+				Data: &ateapipb.SnapshotInfo_Local{Local: localInfo},
 			}
 			latestActor.InProgressSnapshot = ""
 		}

cmd/ateapi/internal/controlapi/workflow_pause_test.go

@@ -0,0 +1,116 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package controlapi
+
+import (
+	"context"
+	"testing"
+
+	"github.com/agent-substrate/substrate/cmd/ateapi/internal/store/storetest"
+	"github.com/agent-substrate/substrate/pkg/proto/ateapipb"
+)
+
+// TestFinalizePausedStep_WorkerGone reproduces the scenario where the worker pod
+// disappears from the DB during pause finalization, so the node it ran on is
+// unknown.
+//
+// Old behavior: NodeVmsWithLocalSnapshots = []string{""}, which made
+// findFreeWorker search for a worker with node name "", never found, a
+// permanent "no free workers available" on resume.
+//
+// Current behavior: NodeVmsWithLocalSnapshots is left nil, and the actor is
+// crashed instead of left PAUSED, since a local snapshot with an unknown node
+// can never be safely resumed.
+func TestFinalizePausedStep_WorkerGone(t *testing.T) {
+	st, cleanup := storetest.SetupTestStore(t)
+	defer cleanup()
+
+	ctx := context.Background()
+	const atespace, actorName = "team-a", "actor-1"
+
+	actor := &ateapipb.Actor{
+		Metadata:           &ateapipb.ResourceMetadata{Atespace: atespace, Name: actorName},
+		Status:             ateapipb.Actor_STATUS_PAUSING,
+		AteomPodNamespace:  "default",
+		AteomPodName:       "worker-pod-1",
+		WorkerPoolName:     "pool1",
+		InProgressSnapshot: "snap-prefix",
+	}
+	if _, err := st.CreateActor(ctx, actor); err != nil {
+		t.Fatalf("CreateActor: %v", err)
+	}
+	// Intentionally NOT creating the worker in store, simulates worker already gone.
+
+	step := &FinalizePausedStep{store: st}
+	input := &PauseInput{Atespace: atespace, ActorName: actorName}
+	state := &PauseState{}
+	if err := step.Execute(ctx, input, state); err != nil {
+		t.Fatalf("Execute: %v", err)
+	}
+
+	got, err := st.GetActor(ctx, atespace, actorName)
+	if err != nil {
+		t.Fatalf("GetActor: %v", err)
+	}
+
+	if got.GetStatus() != ateapipb.Actor_STATUS_CRASHED {
+		t.Errorf("status = %v, want CRASHED (node name unknown, cannot resume safely)", got.GetStatus())
+	}
+	for _, n := range got.GetLatestSnapshotInfo().GetLocal().GetNodeVmsWithLocalSnapshots() {
+		if n == "" {
+			t.Errorf("BUG: empty string in NodeVmsWithLocalSnapshots, findFreeWorker would never match")
+		}
+	}
+
+	state.Actor = got
+	done, err := step.IsComplete(ctx, input, state)
+	if err != nil {
+		t.Fatalf("IsComplete: %v", err)
+	}
+	if !done {
+		t.Error("IsComplete = false, want true once the actor is CRASHED and the worker is freed")
+	}
+}
+
+// TestFindFreeWorker_EmptyNodeRestriction shows the root symptom the fix
+// avoids: old code wrote []string{""} into NodeVmsWithLocalSnapshots when the
+// node name was unknown, and findFreeWorker required worker.NodeName == "",
+// which never matches a real worker.
+func TestFindFreeWorker_EmptyNodeRestriction(t *testing.T) {
+	workers := []*ateapipb.Worker{
+		{WorkerNamespace: "default", WorkerPool: "pool1", WorkerPod: "w1", NodeName: "node1"},
+		{WorkerNamespace: "default", WorkerPool: "pool1", WorkerPod: "w2", NodeName: "node2"},
+	}
+
+	s := &AssignWorkerStep{}
+
+	// Old behavior: []string{""}, no worker has NodeName == "", returns nil.
+	got, err := s.findFreeWorker(workers, "", nil, nil, []string{""})
+	if err != nil {
+		t.Fatalf("findFreeWorker: %v", err)
+	}
+	if got != nil {
+		t.Errorf("expected nil with old buggy input, got %v", got)
+	}
+
+	// Fixed behavior: nil restrictions, any free worker matches.
+	got, err = s.findFreeWorker(workers, "", nil, nil, nil)
+	if err != nil {
+		t.Fatalf("findFreeWorker: %v", err)
+	}
+	if got == nil {
+		t.Error("expected a worker with nil restrictions, got nil")
+	}
+}