fix: data races detected by -race in SessionManager.Save and poller test

- Copy-on-write in SessionManager.Save (mutate keeps old pointer safe)
- TurnCount/fields snapshot under lock before unlock
- Test races fixed: atomic.Int32 for attempts counter in poller test
- Tests updated for copy-on-write pointer semantics (re-fetch after Save)
- Full project passes: go test -short -race ./... — 19/19 packages OK

Author: molty3000

internal/telegram/poller_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 )
@@ -633,10 +634,10 @@ func TestPoller_Start_FatalError(t *testing.T) {
 }
 
 func TestPoller_Start_RetriesOnTransientError(t *testing.T) {
-	attempts := 0
+	var attempts atomic.Int32
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		attempts++
-		if attempts < 3 {
+		attempts.Add(1)
+		if attempts.Load() < 3 {
 			failResponse(w, 502, "Bad Gateway")
 			return
 		}
@@ -670,7 +671,7 @@ func TestPoller_Start_RetriesOnTransientError(t *testing.T) {
 	if err != context.DeadlineExceeded && err != context.Canceled {
 		t.Errorf("Start returned %v, want context deadline/cancel error", err)
 	}
-	if attempts < 3 {
-		t.Errorf("attempts = %d, want >= 3", attempts)
+	if attempts.Load() < 3 {
+		t.Errorf("attempts = %d, want >= 3", attempts.Load())
 	}
 }

internal/telegram/session.go

@@ -105,9 +105,14 @@ func (sm *SessionManager) Save(chatID int64, messages []llm.Message) error {
 	sm.Mu.Lock()
 	cs, ok := sm.Cache[chatID]
 	if ok {
-		cs.Messages = messages
-		cs.LastActive = time.Now()
-		cs.TurnCount++
+		// Copy-on-write: create a new ChatSession so existing pointers
+		// held by Load() callers are not mutated, avoiding data races.
+		updated := *cs
+		updated.Messages = messages
+		updated.LastActive = time.Now()
+		updated.TurnCount++
+		cs = &updated
+		sm.Cache[chatID] = cs
 	} else {
 		cs = &ChatSession{
 			ChatID:     chatID,
@@ -118,15 +123,18 @@ func (sm *SessionManager) Save(chatID int64, messages []llm.Message) error {
 		}
 		sm.Cache[chatID] = cs
 	}
+	// Snapshot fields needed after unlock to avoid data race:
+	sessionID := cs.SessionID
+	createdAt := cs.CreatedAt
+	turnCount := cs.TurnCount
 	sm.Mu.Unlock()
 
-	now := time.Now()
 	sess := &session.Session{
-		ID:        cs.SessionID,
-		CreatedAt: cs.CreatedAt,
-		UpdatedAt: now,
+		ID:        sessionID,
+		CreatedAt: createdAt,
+		UpdatedAt: time.Now(),
 		Model:     "",
-		Turns:     cs.TurnCount,
+		Turns:     turnCount,
 		Task:      fmt.Sprintf("tg-%d", chatID),
 		Messages:  messages,
 	}

internal/telegram/session_test.go

@@ -277,11 +277,12 @@ func TestSave_incrementsTurnCount(t *testing.T) {
 		t.Errorf("TurnCount = %d, want 1 after first save", cs.TurnCount)
 	}
 
-	// Second save → TurnCount = 2
+	// Second save → re-fetch from cache to verify increment
 	err = sm.Save(chatID, []llm.Message{{Role: "user", Content: "turn 2"}})
 	if err != nil {
 		t.Fatalf("second Save failed: %v", err)
 	}
+	cs, _ = sm.GetOrCreate(chatID)
 	if cs.TurnCount != 2 {
 		t.Errorf("TurnCount = %d, want 2 after second save", cs.TurnCount)
 	}
@@ -291,14 +292,10 @@ func TestSave_incrementsTurnCount(t *testing.T) {
 	if err != nil {
 		t.Fatalf("third Save failed: %v", err)
 	}
+	cs, _ = sm.GetOrCreate(chatID)
 	if cs.TurnCount != 3 {
 		t.Errorf("TurnCount = %d, want 3 after third save", cs.TurnCount)
 	}
-
-	// Verify disk also has the right turn count.
-	if cs.TurnCount != 3 {
-		t.Errorf("TurnCount = %d, want 3", cs.TurnCount)
-	}
 }
 
 // ---------------------------------------------------------------------------
@@ -497,6 +494,11 @@ func TestAppendMessage(t *testing.T) {
 	if err != nil {
 		t.Fatalf("second AppendMessage failed: %v", err)
 	}
+	// Re-fetch after Save (copy-on-write replaces cache pointer).
+	cs, err = sm.GetOrCreate(chatID)
+	if err != nil {
+		t.Fatalf("GetOrCreate after second append failed: %v", err)
+	}
 	if len(cs.Messages) != 2 {
 		t.Errorf("Messages length = %d, want 2", len(cs.Messages))
 	}