From 94c3f6dcb4ce078aea959a157daa806f635311f9 Mon Sep 17 00:00:00 2001
From: cabbage <root@everdream.xyz>
Date: Sun, 6 Sep 2026 09:18:37 +0000
Subject: [PATCH] fix: fence command events by dispatch generation

---
 internal/server/session/agent_server.go      |  6 ++--
 internal/server/session/agent_server_test.go |  4 +--
 internal/server/store/event.go               | 31 ++++++++++++--------
 3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/internal/server/session/agent_server.go b/internal/server/session/agent_server.go
index b0b78f1..13d9ac1 100644
--- a/internal/server/session/agent_server.go
+++ b/internal/server/session/agent_server.go
@@ -244,7 +244,7 @@ func (server *AgentServer) serveConnection(parent context.Context, connection *w
 			continue
 		}
 		if event := envelope.GetCommandEvent(); event != nil {
-			appendEvent, eventErr := eventAppendFromWire(event, hello.GetClientId(), server.now())
+			appendEvent, eventErr := eventAppendFromWire(event, hello.GetClientId(), registration.Generation, server.now())
 			if eventErr != nil {
 				server.close(connection, websocket.StatusPolicyViolation, "invalid command event")
 				return
@@ -263,7 +263,7 @@ func (server *AgentServer) serveConnection(parent context.Context, connection *w
 	}
 }
 
-func eventAppendFromWire(event *rvboxv1.CommandEvent, clientID string, receipt time.Time) (store.EventAppend, error) {
+func eventAppendFromWire(event *rvboxv1.CommandEvent, clientID string, generation uint64, receipt time.Time) (store.EventAppend, error) {
 	issue, err := domain.ParseUUIDv7(event.GetIssueUuid())
 	if err != nil {
 		return store.EventAppend{}, err
@@ -274,7 +274,7 @@ func eventAppendFromWire(event *rvboxv1.CommandEvent, clientID string, receipt t
 	}
 	var immutable [32]byte
 	copy(immutable[:], event.GetImmutableEventSha256())
-	result := store.EventAppend{IssueUUID: [16]byte(issue), ClientID: clientID, EventSeq: event.GetEventSeq(), ObservedUnixNano: event.GetObservedAt().AsTime().UnixNano(), ReceiptUnixNano: receipt.UnixNano(), EventType: eventType(event), Compression: 1, RawLength: uint64(len(payload)), Payload: payload, ImmutableSHA256: immutable}
+	result := store.EventAppend{IssueUUID: [16]byte(issue), ClientID: clientID, SessionGeneration: generation, EventSeq: event.GetEventSeq(), ObservedUnixNano: event.GetObservedAt().AsTime().UnixNano(), ReceiptUnixNano: receipt.UnixNano(), EventType: eventType(event), Compression: 1, RawLength: uint64(len(payload)), Payload: payload, ImmutableSHA256: immutable}
 	if output := event.GetOutput(); output != nil {
 		result.Stream = uint16(output.GetStream())
 		result.Output = true
diff --git a/internal/server/session/agent_server_test.go b/internal/server/session/agent_server_test.go
index 050a170..6564489 100644
--- a/internal/server/session/agent_server_test.go
+++ b/internal/server/session/agent_server_test.go
@@ -116,8 +116,8 @@ func TestWireEventAppendCarriesClientBinding_HP_EVENT_01(t *testing.T) {
 		t.Fatal(err)
 	}
 	event.ImmutableEventSha256 = digest[:]
-	appendEvent, err := eventAppendFromWire(event, "client-a", time.Now())
-	if err != nil || appendEvent.ClientID != "client-a" || appendEvent.EventSeq != 1 || appendEvent.EventType != 4 || appendEvent.ImmutableSHA256 != digest {
+	appendEvent, err := eventAppendFromWire(event, "client-a", 7, time.Now())
+	if err != nil || appendEvent.ClientID != "client-a" || appendEvent.SessionGeneration != 7 || appendEvent.EventSeq != 1 || appendEvent.EventType != 4 || appendEvent.ImmutableSHA256 != digest {
 		t.Fatalf("wire event append = %#v, %v", appendEvent, err)
 	}
 }
diff --git a/internal/server/store/event.go b/internal/server/store/event.go
index 738a3b3..d5b2d89 100644
--- a/internal/server/store/event.go
+++ b/internal/server/store/event.go
@@ -32,19 +32,20 @@ type FaultInjectorFunc func(name string) error
 func (function FaultInjectorFunc) Checkpoint(name string) error { return function(name) }
 
 type EventAppend struct {
-	IssueUUID        [16]byte
-	ClientID         string
-	EventSeq         uint64
-	ObservedUnixNano int64
-	ReceiptUnixNano  int64
-	EventType        uint16
-	Stream           uint16
-	Compression      uint16
-	RawLength        uint64
-	Payload          []byte
-	ImmutableSHA256  [32]byte
-	Output           bool
-	UseCloseout      bool
+	IssueUUID         [16]byte
+	ClientID          string
+	SessionGeneration uint64
+	EventSeq          uint64
+	ObservedUnixNano  int64
+	ReceiptUnixNano   int64
+	EventType         uint16
+	Stream            uint16
+	Compression       uint16
+	RawLength         uint64
+	Payload           []byte
+	ImmutableSHA256   [32]byte
+	Output            bool
+	UseCloseout       bool
 }
 
 type EventAppendResult struct {
@@ -91,6 +92,10 @@ JOIN storage_counters ON storage_counters.singleton = 1 WHERE commands.issue_uui
 		query += ` AND commands.client_id = ?`
 		arguments = append(arguments, event.ClientID)
 	}
+	if event.SessionGeneration != 0 {
+		query += ` AND commands.target_session_generation = ?`
+		arguments = append(arguments, event.SessionGeneration)
+	}
 	err = database.QueryRowContext(ctx, query, arguments...).Scan(
 		&lastSequence, &commandOutputCharged, &commandCharged, &closeoutRemaining, &clientID, &clientCharged, &serverCharged)
 	if errors.Is(err, sql.ErrNoRows) {