fix: sync session membership routing fixes

internal/mtprotoedge/session_membership_gen_test.go

@@ -0,0 +1,95 @@
+package mtprotoedge
+
+import (
+	"testing"
+	"time"
+
+	"go.uber.org/zap/zaptest"
+)
+
+// TestSetSessionChannelMembershipsDetectsConcurrentIncrementalUpdates 验证全量
+// membership 同步的丢失更新防护：同步方在读持久成员列表前采样修订号，读取窗口内
+// 若发生增量 join/leave（另一设备操作经 Add/RemoveUserChannelMembership 落索引），
+// 携带过期修订号的全量替换必须改走并集合并（不得覆盖增量），并保持
+// membershipsSynced=false 促使下一条 RPC 重试全量同步收敛。
+func TestSetSessionChannelMembershipsDetectsConcurrentIncrementalUpdates(t *testing.T) {
+	sm := NewSessionManager(zaptest.NewLogger(t))
+	raw := [8]byte{1, 2, 3}
+	c := &Conn{sessionID: 42, authKeyID: raw}
+	sm.Register(c)
+	sm.BindUserForAuthKey(raw, 42, 100)
+	sm.SetReceivesUpdatesForAuthKey(raw, 42, true)
+
+	// 同步方采样修订号后、全量列表落地前，用户在另一台设备加入了频道 7。
+	gen := sm.ChannelMembershipGeneration(raw, 42)
+	sm.AddUserChannelMembership(100, 7)
+	// 基于旧快照的全量列表（只有频道 5，不含 7）携带过期修订号落地。
+	sm.SetSessionChannelMemberships(raw, 42, 100, []int64{5}, gen)
+
+	if got := sm.OnlineChannelMemberUserIDs(7, 10); len(got) != 1 || got[0] != 100 {
+		t.Fatalf("channel 7 members = %v, want [100]: full replace overwrote the in-window incremental join", got)
+	}
+	if got := sm.OnlineChannelMemberUserIDs(5, 10); len(got) != 1 || got[0] != 100 {
+		t.Fatalf("channel 5 members = %v, want [100]: merge path must still apply the full list", got)
+	}
+	if sm.ReceivesUpdatesForAuthKey(raw, 42) {
+		t.Fatal("session fully ready despite raced membership sync; retry would never happen")
+	}
+
+	// 重试：新修订号下的全量同步正常替换并置就绪。
+	sm.SetSessionChannelMemberships(raw, 42, 100, []int64{5, 7}, sm.ChannelMembershipGeneration(raw, 42))
+	if !sm.ReceivesUpdatesForAuthKey(raw, 42) {
+		t.Fatal("session not ready after clean resync")
+	}
+
+	// 反方向：窗口内被移出频道 5，stale 全量含 5 → 合并会短暂保留 stale 条目
+	// （fan-out 前的 PG active 复核兜底），但必须保持未就绪等待重试。
+	gen = sm.ChannelMembershipGeneration(raw, 42)
+	sm.RemoveUserChannelMembership(100, 5)
+	sm.SetSessionChannelMemberships(raw, 42, 100, []int64{5, 7}, gen)
+	if sm.ReceivesUpdatesForAuthKey(raw, 42) {
+		t.Fatal("session ready despite raced removal during sync")
+	}
+	sm.SetSessionChannelMemberships(raw, 42, 100, []int64{7}, sm.ChannelMembershipGeneration(raw, 42))
+	if got := sm.OnlineChannelMemberUserIDs(5, 10); len(got) != 0 {
+		t.Fatalf("channel 5 members after resync = %v, want empty", got)
+	}
+	if !sm.ReceivesUpdatesForAuthKey(raw, 42) {
+		t.Fatal("session not ready after final resync")
+	}
+}
+
+// TestRegisterEvictsOldestSessionAtCap 验证同 raw auth_key session 数触顶时驱逐的是
+// 建连最早的连接，而不是 map 迭代顺序下的随机一个（随机可能误杀刚建立的活跃连接）。
+func TestRegisterEvictsOldestSessionAtCap(t *testing.T) {
+	sm := NewSessionManager(zaptest.NewLogger(t))
+	raw := [8]byte{9}
+	base := time.Unix(1_700_000_000, 0)
+
+	const oldestSession = int64(100)
+	for i := 0; i < maxSessionsPerAuthKey; i++ {
+		sid := int64(i + 1)
+		created := base.Add(time.Duration(i+1) * time.Second)
+		if sid == oldestSession {
+			created = base // 唯一早于所有其它连接的时间戳，且故意不在注册顺序首位。
+		}
+		sm.Register(&Conn{sessionID: sid, authKeyID: raw, createdAt: created})
+	}
+
+	sm.Register(&Conn{sessionID: 9999, authKeyID: raw, createdAt: base.Add(time.Hour)})
+
+	sm.mu.RLock()
+	_, oldestAlive := sm.bySession[sessionKey{authKeyID: raw, sessionID: oldestSession}]
+	_, newestAlive := sm.bySession[sessionKey{authKeyID: raw, sessionID: 9999}]
+	total := len(sm.byAuthKey[raw])
+	sm.mu.RUnlock()
+	if oldestAlive {
+		t.Fatal("oldest session survived eviction at cap")
+	}
+	if !newestAlive {
+		t.Fatal("newly registered session missing after eviction")
+	}
+	if total != maxSessionsPerAuthKey {
+		t.Fatalf("sessions for auth key = %d, want cap %d", total, maxSessionsPerAuthKey)
+	}
+}