test(canvas): restore a lifetime canceled before its first request

internal/platform/canvas_model_integration_test.go

@@ -370,4 +370,19 @@ func TestCanonicalModelMigrationAndIncrementalLifecycle(t *testing.T) {
 		t.Fatal("compacted projection receipt was not recoverable by its original key")
 	}
 
+	// A locally canceled incarnation was never sent; undo may first publish incarnation 2.
+	locallyElidedID := modelTestID(5201)
+	locallyRestored := modelTestNode(locallyElidedID, innerCanvas)
+	locallyRestored["incarnation"] = float64(2)
+	edit(1020, map[string]int64{innerCanvas: model.Versions[innerCanvas]}, modelChange{Kind: "element", ID: locallyElidedID, Before: modelJSON(nil), After: modelJSON(locallyRestored)})
+	model = read()
+	if modelInt(model.Elements[locallyElidedID]["incarnation"]) != 2 || model.Tombstones[locallyElidedID] != 0 {
+		t.Fatal("local elision undo reused a canceled life or invented an ACK tombstone")
+	}
+	staleElisionKey := modelTestID(1021)
+	staleElision := modelBatch{ProtocolVersion: 2, RequestID: staleElisionKey, Expected: map[string]int64{innerCanvas: model.Versions[innerCanvas]}, Operations: []modelOperation{{ID: modelTestID(22007), Changes: []modelChange{{Kind: "field", Target: modelTarget{ID: locallyElidedID, Incarnation: 1}, Field: "data.title", Before: modelJSON(locallyElidedID), After: modelJSON("stale local callback")}}}}}
+	if call("POST", base+"/model/operations", staleElision, staleElisionKey, 409)["status"] != "not-applied" || !modelEqual(read().Elements[locallyElidedID], locallyRestored) {
+		t.Fatal("a callback from the locally canceled incarnation changed its restored successor")
+	}
+
 }