Fix MQTT recovery admission and retained client buffer sizing

test/test_firmware_ram.py

@@ -225,6 +225,9 @@ class FirmwareRamTest(unittest.TestCase):
                 self.assertEqual(profile["cold_start_allocation_allowance_bytes"], 16384)
                 self.assertEqual(profile["cold_start_dma_admission_free_bytes"], 32768)
                 self.assertEqual(profile["cold_start_dma_admission_contiguous_bytes"], 8192)
+                self.assertEqual(profile["restart_allocation_allowance_bytes"], 8192)
+                self.assertEqual(profile["restart_dma_admission_free_bytes"], 24576)
+                self.assertEqual(profile["restart_dma_admission_contiguous_bytes"], 8192)
                 self.assertFalse(profile["maximum_runtime_load_qualified"])
                 self.assertFalse(profile["physical_validation_performed"])
         ordinary = ram.requirements("ESP32_PLATFORM", {"BOARD_HAS_PSRAM": 1}, "v4_companion")
@@ -280,6 +283,8 @@ class FirmwareRamTest(unittest.TestCase):
             ("client_task_priority", "kClientTaskPriority"),
             ("cold_start_allocation_allowance_bytes", "kColdStartAllowanceBytes"),
             ("cold_start_dma_admission_contiguous_bytes", "kColdStartLargestBytes"),
+            ("restart_allocation_allowance_bytes", "kRestartAllowanceBytes"),
+            ("restart_dma_admission_contiguous_bytes", "kRestartLargestBytes"),
             ("dma_admission_free_bytes", "kDmaReserveBytes"),
             ("dma_admission_contiguous_bytes", "kDmaLargestBytes"),
             ("tls_internal_admission_free_bytes", "kTlsInternalFreeBytes"),
@@ -289,6 +294,8 @@ class FirmwareRamTest(unittest.TestCase):
                 self.assertIn(f"{name} = {profile[key]};", source)
         self.assertEqual(profile["cold_start_dma_admission_free_bytes"],
                          profile["dma_admission_free_bytes"] + profile["cold_start_allocation_allowance_bytes"])
+        self.assertEqual(profile["restart_dma_admission_free_bytes"],
+                         profile["dma_admission_free_bytes"] + profile["restart_allocation_allowance_bytes"])
 
     def test_combined_rak_budgets_uart_beside_exclusive_ethernet_and_ota(self):
         defines = {

test/test_mqtt_connection_admission.py

@@ -16,6 +16,7 @@ POLICY_PREAMBLE = r'''
 #include <cstdint>
 #include "helpers/MQTTConnectionAdmission.h"
 namespace Admission = MQTTConnectionAdmission;
+using MemoryState = Admission::ClientMemoryState;
 '''
 
 HEAP_PREAMBLE = POLICY_PREAMBLE + r'''
@@ -54,7 +55,8 @@ constexpr int RUNTIME_MQTT_SLOTS = 6;
 struct { size_t size = 0; size_t getPsramSize() const { return size; } } ESP;
 struct Preset { const char* server_url; };
 struct Client {
-  bool started = false;
+  bool initialized = false, started = false;
+  bool isInitialized() const { return initialized; }
   bool isStarted() const { return started; }
 };
 struct MQTTBridge {
@@ -92,20 +94,23 @@ class MqttConnectionAdmissionTest(unittest.TestCase):
         self.compile_run(POLICY_PREAMBLE + r'''
 int main() {
   // A large aggregate heap cannot compensate for a fragmented DMA region.
-  assert(!Admission::canStart(true, true, false, 100000, 4095));
-  assert(!Admission::canStart(true, true, false, 16383, 20000));
-  assert(Admission::canStart(true, true, false, 16384, 4096));
-  assert(Admission::canStart(false, false, false, 16384, 4096));
-  assert(!Admission::canStart(false, false, false, 16383, 4096));
-  assert(!Admission::canStart(false, false, false, 16384, 4095));
+  assert(!Admission::canStart(true, true, MemoryState::Started, 100000, 4095));
+  assert(!Admission::canStart(true, true, MemoryState::Started, 16383, 20000));
+  assert(Admission::canStart(true, true, MemoryState::Started, 16384, 4096));
+  assert(Admission::canStart(false, false, MemoryState::Started, 16384, 4096));
+  assert(!Admission::canStart(false, false, MemoryState::Started, 16383, 4096));
+  assert(!Admission::canStart(false, false, MemoryState::Started, 16384, 4095));
 
   // Without PSRAM, TLS also needs a full record allocation and session budget.
-  for (int cold = 0; cold <= 1; ++cold) {
-    assert(!Admission::canStart(false, true, cold, 61439, 20000));
-    assert(!Admission::canStart(false, true, cold, 100000, 17407));
-    assert(Admission::canStart(false, true, cold, 61440, 17408));
+  const MemoryState states[] = {MemoryState::Uninitialized, MemoryState::Stopped,
+                                MemoryState::Started};
+  for (MemoryState state : states) {
+    assert(!Admission::canStart(false, true, state, 61439, 20000));
+    assert(!Admission::canStart(false, true, state, 100000, 17407));
+    assert(Admission::canStart(false, true, state, 61440, 17408));
   }
-  assert(Admission::canStart(true, false, false, 16384, 4096));
+  assert(Admission::canStart(true, false, MemoryState::Started, 16384, 4096));
+  assert(!Admission::canStart(true, false, static_cast<MemoryState>(255), SIZE_MAX, SIZE_MAX));
 
   // A new SDK task needs its stack and ordinary startup allocations in
   // addition to the DMA reserve, including plaintext and PSRAM-backed TLS.
@@ -113,12 +118,19 @@ int main() {
   assert(Admission::kClientTaskPriority == 5);
   assert(Admission::kColdStartAllowanceBytes == 16384);
   assert(Admission::kColdStartLargestBytes == 8192);
+  assert(Admission::kRestartAllowanceBytes == 8192);
+  assert(Admission::kRestartLargestBytes == 8192);
   for (int psram = 0; psram <= 1; ++psram) {
     for (int tls = 0; tls <= 1; ++tls) {
       if (!psram && tls) continue;  // Larger TLS thresholds checked above.
-      assert(!Admission::canStart(psram, tls, true, 32767, 20000));
-      assert(!Admission::canStart(psram, tls, true, 100000, 8191));
-      assert(Admission::canStart(psram, tls, true, 32768, 8192));
+      assert(!Admission::canStart(psram, tls, MemoryState::Uninitialized, 32767, 20000));
+      assert(!Admission::canStart(psram, tls, MemoryState::Uninitialized, 100000, 8191));
+      assert(Admission::canStart(psram, tls, MemoryState::Uninitialized, 32768, 8192));
+      // An initialized handle retains its ordinary SDK buffers across a stop.
+      // Only the replacement task/TCB is charged beside the DMA reserve.
+      assert(!Admission::canStart(psram, tls, MemoryState::Stopped, 24575, 20000));
+      assert(!Admission::canStart(psram, tls, MemoryState::Stopped, 100000, 8191));
+      assert(Admission::canStart(psram, tls, MemoryState::Stopped, 24576, 8192));
     }
   }
 }
@@ -281,7 +293,7 @@ int main() {
   assert(!bridge.canStartSlotConnection(0));
   Client client;
   bridge._slots[0].client = &client;
-  assert(!bridge.canStartSlotConnection(0));  // Allocated, but task not started.
+  assert(!bridge.canStartSlotConnection(0));  // Wrapper allocated; SDK not initialized.
   dma_free = 32767; dma_largest = 20000;
   assert(!bridge.canStartSlotConnection(0));
   dma_free = 32768; dma_largest = 8191;
@@ -289,6 +301,14 @@ int main() {
   dma_largest = 8192;
   assert(bridge.canStartSlotConnection(0));
 
+  // An initialized but stopped handle needs its task again, not new SDK buffers.
+  client.initialized = true; dma_free = 24575; dma_largest = 20000;
+  assert(!bridge.canStartSlotConnection(0));
+  dma_free = 24576; dma_largest = 8191;
+  assert(!bridge.canStartSlotConnection(0));
+  dma_largest = 8192;
+  assert(bridge.canStartSlotConnection(0));
+
   // A warm reconnect retains the SDK task/buffers and uses the smaller floor.
   client.started = true; dma_free = 16384; dma_largest = 4096;
   assert(bridge.canStartSlotConnection(0));

test/test_mqtt_handshake_scheduler.py

@@ -20,24 +20,43 @@ PREAMBLE = r'''
 #include <cstdint>
 #include <cstdio>
 #include <cstring>
+#include <functional>
 #include <vector>
+#include "helpers/AlertFaultPolicy.h"
 #include "helpers/MQTTConnectionAdmission.h"
 #include "helpers/MQTTConnectionHealth.h"
 #include "helpers/MQTTConnectionPolicy.h"
+#include "helpers/WiFiPowerSave.h"
 #define ESP_PLATFORM 1
 #define MQTT_DEBUG_PRINTLN(...) ((void)0)
 using esp_err_t = int;
 constexpr int ESP_OK = 0, ESP_ERR_INVALID_ARG = 1, ESP_ERR_INVALID_STATE = 2;
 constexpr int ESP_ERR_NO_MEM = 3, RUNTIME_MQTT_SLOTS = 6, WL_CONNECTED = 1;
+constexpr int WL_DISCONNECTED = 0, WIFI_POWER_11dBm = 11;
+using wl_status_t = int;
+using wifi_ps_type_t = int;
+constexpr int WIFI_PS_NONE = 0, WIFI_PS_MAX_MODEM = 1, WIFI_PS_MIN_MODEM = 2;
+namespace mesh { namespace wifi {
+constexpr bool kPrimaryEspNowRadio = false;
+bool enforceStationChannel() { return true; }
+} }
+bool mqttStationWiFiMutationAllowed() { return true; }
+void esp_wifi_set_ps(wifi_ps_type_t) {}
 constexpr int MQTT_AUTH_JWT = 1;
 constexpr uint32_t MALLOC_CAP_INTERNAL = 1, MALLOC_CAP_DMA = 2;
 static uint32_t clock_ms = 1000;
 static unsigned long wall_seconds = 1800000000;
 static size_t dma_free = 100000, dma_largest = 20000;
+static unsigned long s_wifi_connected_at = 0;
 uint32_t millis() { return clock_ms; }
 unsigned long fake_time(void*) { return wall_seconds; }
 #define time fake_time
-struct { int status() const { return WL_CONNECTED; } } WiFi;
+struct {
+  int state = WL_CONNECTED;
+  int status() const { return state; }
+  void setTxPower(int) {}
+  void disconnect() { state = WL_DISCONNECTED; }
+} WiFi;
 struct { size_t size = 2097152; size_t getPsramSize() const { return size; } } ESP;
 size_t heap_caps_get_free_size(uint32_t caps) {
   assert(caps == (MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA)); return dma_free;
@@ -56,12 +75,28 @@ bool mqttPresetEnforcesTokenExp(const Preset* preset) {
   return preset && preset->enforce_exp;
 }
 struct PsychicMqttClient {
-  bool started = false, live = false;
-  int starts = 0, reconnects = 0, bounces = 0, credentials = 0;
+  bool initialized = false, started = false, live = false, model_task_heap = false;
+  int starts = 0, reconnects = 0, bounces = 0, credentials = 0, stops = 0;
+  std::function<void()> disconnected;
+  bool isInitialized() const { return initialized; }
   bool isStarted() const { return started; }
   bool connected() const { return live; }
-  int connect() { ++starts; started = true; return ESP_OK; }
+  int connect() {
+    ++starts;
+    if (model_task_heap) {
+      assert(initialized && !started && dma_free >= 6536);
+      dma_free -= 6536;
+    }
+    initialized = started = true;
+    return ESP_OK;
+  }
   int reconnect() { ++reconnects; return ESP_OK; }
+  void disconnect() {
+    ++stops;
+    if (model_task_heap && started) dma_free += 6536;
+    started = live = false;
+    if (disconnected) disconnected();
+  }
   void softDisconnect() {
     ++bounces; live = false;
     // Releasing the old internal TLS session creates room for its replacement.
@@ -92,8 +127,19 @@ struct MQTTBridge {
   bool _slot_force_jwt_mint[RUNTIME_MQTT_SLOTS] = {};
   void* _identity = this;
   bool _slots_setup_done = true;
+  bool _wifi_status_initialized = true, _manage_wifi = false;
+  wl_status_t _last_wifi_status = WL_CONNECTED;
+  unsigned long _last_wifi_check = 0, _last_wifi_reconnect_attempt = 0;
+  uint8_t _wifi_reconnect_backoff_attempt = 0, _wifi_power_save = 1;
+  struct { bool canonical_wifi = false; } _node_info;
+  struct Observer { uint8_t wifi_power_save = 1; } observer;
+  Observer* _obs = &observer;
+  AlertFaultPolicy::OutageSnapshot _wifi_outage{};
   unsigned long _last_slot_reconnect_ms = 0;
   int _max_active_slots = 5, mints = 0;
+  AlertFaultPolicy::OutageSnapshot wifiOutage() const { return _wifi_outage; }
+  void setWifiOutage(AlertFaultPolicy::OutageSnapshot snapshot) { _wifi_outage = snapshot; }
+  void beginWiFiStation() {}
   const char* _jwt_username = "jwt";
   static const unsigned long SLOT_SETUP_RETRY_INTERVAL = 60000;
   std::vector<int> setups;
@@ -127,6 +173,7 @@ struct MQTTBridge {
   esp_err_t reconnectSlotClient(int index);
   unsigned long slotTokenLifetime(int index) const;
   void maintainSlotConnections();
+  bool handleWiFiConnection(unsigned long);
   void maintainSlotConnection(int, unsigned long, unsigned long, bool, bool&, bool&);
 };
 '''
@@ -142,6 +189,7 @@ class MqttHandshakeSchedulerTest(unittest.TestCase):
             "bool MQTTBridge::canStartSlotConnection(int index) const",
             "esp_err_t MQTTBridge::reconnectSlotClient(int index)",
             "unsigned long MQTTBridge::slotTokenLifetime(int index) const",
+            "bool MQTTBridge::handleWiFiConnection(unsigned long now)",
             "void MQTTBridge::maintainSlotConnections()",
             "void MQTTBridge::maintainSlotConnection("))
 
@@ -268,9 +316,10 @@ int main() {
   stopped.client = &bridge.clients[0];
   retained.client = &bridge.clients[1];
   stopped.initial_connect_done = retained.initial_connect_done = true;
+  stopped.client->initialized = retained.client->initialized = true;
   retained.client->started = true;
 
-  // An existing handle with a stopped task needs the cold-start allowance.
+  // An existing handle with a stopped task needs the task-restart allowance.
   // Its deferral must leave this cycle available for the retained SDK task.
   assert(!bridge.canStartSlotConnection(0));
   assert(bridge.canStartSlotConnection(1));
@@ -281,11 +330,11 @@ int main() {
   assert(retained.client->starts == 0 && retained.client->reconnects == 1);
   assert(bridge._slot_attempt_pending[1]);
 
-  // Completion and newly available cold-start headroom allow a real SDK start,
+  // Completion and newly available task-restart headroom allow an SDK start,
   // with no extra delay introduced by the earlier memory-only deferral.
   bridge.complete(1);
   clock_ms += 15000;
-  dma_free = 32768; dma_largest = 8192;
+  dma_free = 24576; dma_largest = 8192;
   bridge.maintainSlotConnections();
   assert(stopped.client->starts == 1 && stopped.client->reconnects == 0);
   assert(stopped.client->isStarted() && bridge._slot_attempt_pending[0]);
@@ -303,7 +352,7 @@ int main() {
   auto& slot = bridge._slots[0];
   slot.preset = &jwt; slot.client = &bridge.clients[0];
   slot.initial_connect_done = slot.connected = true;
-  slot.client->started = slot.client->live = true;
+  slot.client->initialized = slot.client->started = slot.client->live = true;
   slot.token_expires_at = wall_seconds + 120;
   // Before releasing the current TLS session, the full admission check fails.
   dma_free = 20000; dma_largest = 10000;
@@ -321,6 +370,86 @@ int main() {
 }
 ''')
 
+    def test_wifi_loss_restarts_three_retained_clients_without_cold_buffer_double_charge(self):
+        self.compile_run(r'''
+int main() {
+  MQTTBridge bridge;
+  clock_ms = 70000;
+  // The live V4's three-broker measurement left about 22.7 KiB DMA heap.
+  // The SDK seam uses the pinned 6144-byte stack and 344-byte TCB, plus a
+  // simulated 48-byte allocator allowance. Transport/config buffers remain
+  // owned by initialized handles after stop; SDK heap calls are not executed.
+  dma_free = 22768; dma_largest = 22516;
+  for (int i = 0; i < 3; ++i) {
+    auto& slot = bridge._slots[i];
+    slot.client = &bridge.clients[i];
+    slot.initial_connect_done = slot.connected = true;
+    slot.client->initialized = slot.client->started = slot.client->live = true;
+    slot.client->model_task_heap = true;
+    slot.client->disconnected = [&bridge, i] { bridge._slots[i].connected = false; };
+  }
+  bridge._slots[5].enabled = false;
+  WiFi.state = WL_DISCONNECTED;
+  assert(!bridge.handleWiFiConnection(clock_ms));
+  assert(bridge.wifiOutage().down && dma_free == 42376);
+  for (int i = 0; i < 3; ++i) {
+    assert(bridge.clients[i].isInitialized() && !bridge.clients[i].isStarted());
+    assert(bridge.clients[i].stops == 1 && !bridge._slots[i].connected);
+    assert(!bridge._slot_attempt_pending[i]);
+  }
+  bridge.maintainSlotConnections();
+  for (int i = 0; i < 3; ++i) assert(bridge.clients[i].starts == 0);
+
+  clock_ms += 11000;
+  WiFi.state = WL_CONNECTED;
+  assert(bridge.handleWiFiConnection(clock_ms));
+  assert(!bridge.wifiOutage().down);
+  // Restart admission still fails safely if either aggregate or contiguous
+  // headroom is inadequate. Neither failure consumes retry/backoff state.
+  dma_free = 24575;
+  bridge.maintainSlotConnections();
+  dma_free = 24576; dma_largest = 8191;
+  bridge.maintainSlotConnections();
+  for (int i = 0; i < 3; ++i) {
+    assert(bridge.clients[i].starts == 0 && bridge._slots[i].last_reconnect_attempt == 0);
+    assert(bridge._slots[i].reconnect_backoff == 0 && bridge._slots[i].start_failures == 0);
+  }
+
+  dma_free = 42376; dma_largest = 22516;
+  bridge.maintainSlotConnections();
+  assert(bridge.clients[0].starts == 1 && dma_free == 35840);
+  assert(bridge.hasPendingSlotConnection());
+  clock_ms += 3600000;
+  bridge.maintainSlotConnections();
+  assert(bridge.clients[1].starts == 0 && bridge.clients[2].starts == 0);
+  bridge.complete(0);
+  bridge.maintainSlotConnections();
+  assert(bridge.clients[1].starts == 1 && dma_free == 29304);
+  clock_ms += 15000;
+  bridge.maintainSlotConnections();
+  assert(bridge.clients[2].starts == 0);  // Callback, not time, ends a pending attempt.
+  bridge.complete(1);
+  assert(!MQTTConnectionAdmission::canStart(
+      true, true, MQTTConnectionAdmission::ClientMemoryState::Uninitialized,
+      dma_free, dma_largest));
+  assert(bridge.canStartSlotConnection(2));
+  bridge.maintainSlotConnections();
+  assert(bridge.clients[2].starts == 1 && dma_free == 22768);
+  bridge.complete(2);
+  clock_ms += 15000;
+  bridge.maintainSlotConnections();
+  for (int i = 0; i < 3; ++i) {
+    assert(bridge._slots[i].connected && bridge.clients[i].isStarted());
+    assert(bridge.clients[i].starts == 1 && bridge.clients[i].reconnects == 0);
+    assert(bridge._slots[i].start_failures == 0);
+  }
+  // Additional clients still need the full first-start allowance and wait.
+  assert(bridge.setups.empty());
+  assert(!bridge.canStartSlotConnection(3) && !bridge.canStartSlotConnection(4));
+  assert(!bridge.hasPendingSlotConnection());
+}
+''')
+
 
 if __name__ == "__main__":
     unittest.main()

test/test_mqtt_network_timeout.py

@@ -11,6 +11,8 @@ import tempfile
 import unittest
 
 from test_mqtt_transport_results import method
+from test_mqtt_publish_ack import (ARDUINO_HEADER, MQTT_HEADER,
+                                  PREAMBLE as ADAPTER_PREAMBLE)
 
 ROOT = Path(__file__).resolve().parents[1]
 
@@ -86,13 +88,145 @@ int main() {
     assert(buffer_size == 896 && keepalive == 45);
     assert(client._outbox_limit == 16384);
 #else
-    assert(buffer_size == (needs_large ? 896 : 512) && keepalive == 75);
+    assert(buffer_size == 896 && keepalive == 75);
     assert(client._outbox_limit == 8192);
 #endif
   }
 }
 '''
 
+RECONFIGURE_PREAMBLE = r'''
+#include "helpers/MQTTConnectionAdmission.h"
+#include "helpers/MQTTConnectionPolicy.h"
+#define MQTT_DEBUG_PRINTLN(...) ((void)0)
+#define pdMS_TO_TICKS(value) (value)
+constexpr int RUNTIME_MQTT_SLOTS = 2, MQTT_AUTH_JWT = 1;
+constexpr uint32_t MALLOC_CAP_INTERNAL = 1, MALLOC_CAP_DMA = 2;
+static size_t dma_free = 100000, dma_largest = 20000;
+size_t heap_caps_get_free_size(uint32_t caps) {
+  assert(caps == (MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA)); return dma_free;
+}
+size_t heap_caps_get_largest_free_block(uint32_t caps) {
+  assert(caps == (MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA)); return dma_largest;
+}
+struct { size_t getPsramSize() const {
+#ifdef BOARD_HAS_PSRAM
+  return 2097152;
+#else
+  return 0;
+#endif
+} } ESP;
+constexpr const char* MQTT_PRESET_NONE = "none";
+constexpr const char* MQTT_PRESET_CUSTOM = "custom";
+struct MQTTPresetDef { const char* server_url; int auth_type; };
+static const MQTTPresetDef plain_preset{"mqtt://broker", 0};
+static const MQTTPresetDef jwt_preset{"mqtt://broker", MQTT_AUTH_JWT};
+const MQTTPresetDef* findMQTTPreset(const char* name) {
+  if (strcmp(name, "plain") == 0) return &plain_preset;
+  if (strcmp(name, "jwt") == 0) return &jwt_preset;
+  return nullptr;
+}
+bool mqttPresetNeedsSlotCredentials(const MQTTPresetDef*) { return false; }
+bool customEndpointComplete(const char* host, uint16_t port) { return host[0] && port; }
+struct MQTTPrefs {
+  char mqtt_slot_host[RUNTIME_MQTT_SLOTS][64] = {"custom-broker", ""};
+  uint16_t mqtt_slot_port[RUNTIME_MQTT_SLOTS] = {1883, 0};
+  char mqtt_slot_username[RUNTIME_MQTT_SLOTS][32] = {"custom-user", ""};
+  char mqtt_slot_password[RUNTIME_MQTT_SLOTS][32] = {"custom-password", ""};
+  char mqtt_slot_audience[RUNTIME_MQTT_SLOTS][32] = {"custom-audience", ""};
+};
+struct MQTTBridge {
+  struct MQTTSlot {
+    PsychicMqttClient* client = nullptr;
+    bool enabled = false, connected = false, initial_connect_done = false;
+    const MQTTPresetDef* preset = nullptr;
+    char host[64] = {}, broker_uri[128] = {}, username[32] = {}, password[32] = {};
+    char audience[32] = {}, *auth_token = nullptr;
+    uint16_t port = 1883;
+    unsigned long token_expires_at = 0, last_token_renewal = 0;
+    unsigned long last_reconnect_attempt = 0, last_log_time = 0, last_deferred_log_ms = 0;
+    uint8_t reconnect_backoff = 0, max_backoff_failures = 0;
+    bool circuit_breaker_tripped = false;
+  } _slots[RUNTIME_MQTT_SLOTS];
+  std::atomic<bool> _stop_requested{false}, _slot_attempt_pending[RUNTIME_MQTT_SLOTS] = {};
+  bool _slot_force_jwt_mint[RUNTIME_MQTT_SLOTS] = {};
+  bool _initialized = true;
+  int _max_active_slots = 2;
+  MQTTPrefs prefs;
+  MQTTPrefs* _obs = &prefs;
+  bool canActivateSlot(int) const { return true; }
+  bool isSlotReady(int, char*, size_t) const { return true; }
+  bool hasPendingSlotConnection() const;
+  bool canStartSlotConnection(int) const;
+  void optimizeMqttClientConfig(PsychicMqttClient*, bool);
+  void teardownSlot(int, bool force = false);
+  void applySlotPreset(int, const char*);
+  bool setupSlot(int index) {
+    auto& slot = _slots[index];
+    // The setup seam executes the actual optimizer, adapter init/start, and
+    // production admission. Token creation and network callbacks are seams.
+    if (!canStartSlotConnection(index)) return false;
+    if (!slot.client) slot.client = new PsychicMqttClient;
+    optimizeMqttClientConfig(slot.client,
+        (slot.preset && slot.preset->auth_type == MQTT_AUTH_JWT) || slot.audience[0]);
+    slot.client->_mqtt_cfg.uri = "mqtt://broker";
+    slot.client->_mqtt_cfg.broker.address.uri = "mqtt://broker";
+    if (slot.client->connect() != ESP_OK) return false;
+    esp_mqtt_event_t event{MQTT_EVENT_CONNECTED, 0, false};
+    sdk_event_handler(sdk_handler_args, "MQTT", event.event_id, &event);
+    slot.initial_connect_done = slot.connected = true;
+    return true;
+  }
+};
+'''
+
+RECONFIGURE_MAIN = r'''
+int main() {
+  MQTTBridge bridge;
+  auto& slot = bridge._slots[0];
+  bridge.applySlotPreset(0, "plain");
+  assert(slot.client && slot.initial_connect_done && slot.client->isStarted());
+  assert(slot.client->_buffer_capacity == 896);
+  char token[8] = "old-jwt";
+  slot.auth_token = token;
+  bridge.applySlotPreset(0, "jwt");
+  assert(token[0] == '\0' && slot.preset == &jwt_preset);
+  assert(slot.client->_buffer_capacity == 896);
+  bridge.applySlotPreset(0, "plain");
+  assert(initialized_buffer_sizes == std::vector<int>{896});
+  assert(init_calls == 1 && destroy_calls == 0 && slot.client->_buffer_capacity == 896);
+  // A custom broker's audience requests JWT-size buffers through the same
+  // explicit-reconfiguration path and synchronizes its saved fields.
+  bridge.applySlotPreset(0, "custom");
+  assert(slot.preset == nullptr && slot.client->_buffer_capacity == 896);
+  assert(strcmp(slot.host, "custom-broker") == 0 && slot.port == 1883);
+  assert(strcmp(slot.audience, "custom-audience") == 0);
+  assert(strcmp(slot.username, "custom-user") == 0);
+  assert(strcmp(slot.password, "custom-password") == 0);
+  bridge.applySlotPreset(0, "none");
+  assert(!slot.enabled && !slot.initial_connect_done);
+  assert(slot.client && slot.client->isInitialized() && !slot.client->isStarted());
+  assert(init_calls == 1 && destroy_calls == 0);
+  // Reconfiguration retains the initialized client on both board profiles.
+  // It needs the stopped-task floor and never silently shrinks its buffers.
+  dma_free = 24575; dma_largest = 20000;
+  bridge.applySlotPreset(0, "plain");
+  assert(slot.client && !slot.client->isStarted() && !slot.initial_connect_done);
+  assert(init_calls == 1 && destroy_calls == 0);
+  dma_free = 24576;
+  assert(bridge.setupSlot(0));
+  assert(slot.client->_buffer_capacity == 896 && init_calls == 1);
+  const int destructions_before_guard = destroy_calls;
+  bridge.applySlotPreset(-1, "jwt");
+  bridge.applySlotPreset(RUNTIME_MQTT_SLOTS, "jwt");
+  bridge._stop_requested = true;
+  bridge.applySlotPreset(0, "jwt");
+  assert(destroy_calls == destructions_before_guard && slot.client->isStarted());
+  delete slot.client;
+  slot.client = nullptr;
+}
+'''
+
 
 class MqttNetworkTimeoutTest(unittest.TestCase):
     def fixture(self):
@@ -143,6 +277,73 @@ class MqttNetworkTimeoutTest(unittest.TestCase):
     def test_production_optimizer_applies_connection_budget_to_every_config(self):
         self.compile_run(self.fixture())
 
+    def test_production_preset_reconfiguration_retains_uniform_sdk_and_reassembly_buffers(self):
+        compiler = shutil.which("g++") or shutil.which("clang++")
+        self.assertIsNotNone(compiler, "a host C++ compiler is required")
+        adapter = "lib/PsychicMqttClient/src/PsychicMqttClient.cpp"
+        # Reuse the actual-header SDK seam; this bridge fixture needs the full
+        # preset reconfiguration path rather than the publish diagnostic shell.
+        preamble = ADAPTER_PREAMBLE.split("constexpr int RUNTIME_MQTT_SLOTS = 2;", 1)[0]
+        preamble = preamble.replace(
+            'void vTaskDelay(unsigned) { assert(false && "stub disconnect must deliver its event"); }',
+            'void vTaskDelay(unsigned ticks) { assert(ticks == 50); }')
+        source = "#define ESP_PLATFORM 1\n" + preamble + RECONFIGURE_PREAMBLE
+        source += "\n".join(method(adapter, signature) for signature in (
+            "PsychicMqttClient::PsychicMqttClient()",
+            "PsychicMqttClient::~PsychicMqttClient()",
+            "PsychicMqttClient &PsychicMqttClient::setKeepAlive(",
+            "PsychicMqttClient &PsychicMqttClient::setMessageRetransmitTimeout(",
+            "PsychicMqttClient &PsychicMqttClient::setBufferSize(",
+            "PsychicMqttClient &PsychicMqttClient::setNetworkTimeout(",
+            "PsychicMqttClient &PsychicMqttClient::setOutboxLimit(",
+            "PsychicMqttClient &PsychicMqttClient::setTaskStackAndPriority(",
+            "esp_mqtt_client_config_t *PsychicMqttClient::getMqttConfig(",
+            "bool PsychicMqttClient::connected()",
+            "esp_err_t PsychicMqttClient::applyConfig()",
+            "esp_err_t PsychicMqttClient::connect()",
+            "void PsychicMqttClient::disconnect()",
+            "void PsychicMqttClient::forceStop()",
+            "int PsychicMqttClient::subscribe(",
+            "void PsychicMqttClient::_onMqttEventStatic(",
+            "void PsychicMqttClient::_onMqttEvent(",
+            "void PsychicMqttClient::_onConnect(",
+            "void PsychicMqttClient::_onDisconnect(",
+            "void PsychicMqttClient::_onSubscribe(",
+            "void PsychicMqttClient::_onUnsubscribe(",
+            "void PsychicMqttClient::_onPublish(",
+        ))
+        source += "\n".join(method("src/helpers/bridges/MQTTBridge.cpp", signature)
+                            for signature in (
+            "bool MQTTBridge::hasPendingSlotConnection() const",
+            "bool MQTTBridge::canStartSlotConnection(int index) const",
+            "void MQTTBridge::optimizeMqttClientConfig(",
+            "void MQTTBridge::teardownSlot(",
+            "void MQTTBridge::applySlotPreset(",
+        )) + RECONFIGURE_MAIN
+        with tempfile.TemporaryDirectory(prefix="meshcore-mqtt-reconfigure-") as temporary:
+            work = Path(temporary)
+            (work / "Arduino.h").write_text(ARDUINO_HEADER, encoding="ascii")
+            (work / "mqtt_client.h").write_text(MQTT_HEADER, encoding="ascii")
+            (work / "esp_crt_bundle.h").write_text("#pragma once\n", encoding="ascii")
+            path = work / "reconfigure.cpp"
+            path.write_text(source, encoding="ascii")
+            for major in (4, 5):
+                for psram in (False, True):
+                    with self.subTest(idf_major=major, psram=psram):
+                        binary = work / f"reconfigure-{major}-{int(psram)}"
+                        command = [compiler, "-std=c++17", "-Wall", "-Wextra", "-Werror",
+                                   "-Wno-unused-parameter", "-DARDUINO_ARCH_ESP32=1",
+                                   f"-DESP_IDF_VERSION_MAJOR={major}",
+                                   "-I", str(work),
+                                   "-I", str(ROOT / "lib/PsychicMqttClient/src"),
+                                   "-I", str(ROOT / "src"), str(path), "-o", str(binary)]
+                        if psram:
+                            command.insert(1, "-DBOARD_HAS_PSRAM=1")
+                        result = subprocess.run(command, capture_output=True, text=True, timeout=60)
+                        self.assertEqual(result.returncode, 0, result.stderr)
+                        result = subprocess.run([str(binary)], capture_output=True, text=True, timeout=10)
+                        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+
     def test_previous_publish_timeout_fails_configuration_regression(self):
         source = self.fixture()
         old = source.replace(

test/test_mqtt_publish_ack.py

@@ -50,9 +50,13 @@ enum {
 };
 struct esp_mqtt_client_config_t {
   const char* uri;
-  int buffer_size;
+  int buffer_size, keepalive, message_retransmit_timeout, network_timeout_ms;
+  int task_stack, task_prio;
   struct { struct { const char* uri; } address; } broker;
-  struct { int size; } buffer;
+  struct { int size, out_size; } buffer;
+  struct { int keepalive, message_retransmit_timeout; } session;
+  struct { int timeout_ms; } network;
+  struct { int stack_size, priority; } task;
 };
 struct esp_mqtt_error_codes_t { int unused; };
 struct esp_mqtt_event_t { int event_id, msg_id; bool session_present; };
@@ -68,6 +72,7 @@ PREAMBLE = r'''
 #include <cstring>
 #include <functional>
 #include <utility>
+#include <vector>
 // Preinclude the standard headers so this seam only opens adapter visibility.
 #define private public
 #include "PsychicMqttClient.h"
@@ -90,25 +95,35 @@ const char* esp_err_to_name(int) { return "mock"; }
 static int publish_result = 0, enqueue_result = 41, outbox_size = 0;
 static int publish_calls = 0, enqueue_calls = 0, config_calls = 0;
 static int start_calls = 0, reconnect_calls = 0, receive_events = 0, error_events = 0;
+static int init_calls = 0, destroy_calls = 0, stop_calls = 0;
+static int start_result = ESP_OK, register_result = ESP_OK;
+static bool fail_init = false;
+static std::vector<int> initialized_buffer_sizes;
 using EventHandler = void(*)(void*, esp_event_base_t, int32_t, void*);
 static EventHandler sdk_event_handler = nullptr;
 static void* sdk_handler_args = nullptr;
-void* esp_mqtt_client_init(esp_mqtt_client_config_t*) {
-  return reinterpret_cast<void*>(1);
+void* esp_mqtt_client_init(esp_mqtt_client_config_t* config) {
+  ++init_calls;
+#if ESP_IDF_VERSION_MAJOR == 5
+  initialized_buffer_sizes.push_back(config->buffer.size);
+#else
+  initialized_buffer_sizes.push_back(config->buffer_size);
+#endif
+  return fail_init ? nullptr : reinterpret_cast<void*>(1);
 }
 int esp_mqtt_client_register_event(void*, int, EventHandler handler, void* args) {
   sdk_event_handler = handler;
   sdk_handler_args = args;
-  return ESP_OK;
+  return register_result;
 }
-int esp_mqtt_client_destroy(void*) { return ESP_OK; }
+int esp_mqtt_client_destroy(void*) { ++destroy_calls; return ESP_OK; }
 int esp_mqtt_set_config(void*, esp_mqtt_client_config_t*) {
   ++config_calls;
   return ESP_OK;
 }
-int esp_mqtt_client_start(void*) { ++start_calls; return ESP_OK; }
+int esp_mqtt_client_start(void*) { ++start_calls; return start_result; }
 int esp_mqtt_client_reconnect(void*) { ++reconnect_calls; return ESP_OK; }
-int esp_mqtt_client_stop(void*) { return ESP_OK; }
+int esp_mqtt_client_stop(void*) { ++stop_calls; return ESP_OK; }
 int esp_mqtt_client_disconnect(void*) {
   assert(sdk_event_handler != nullptr);
   esp_mqtt_event_t event{MQTT_EVENT_DISCONNECTED, 0, false};
@@ -318,7 +333,7 @@ int main() {
 
 
 class MqttPublishAckTests(unittest.TestCase):
-    def test_production_publish_events_and_slot_diagnostics(self):
+    def compile_run(self, main):
         compiler = shutil.which("g++")
         if not compiler:
             self.skipTest("g++ is unavailable")
@@ -331,6 +346,7 @@ class MqttPublishAckTests(unittest.TestCase):
             "esp_err_t PsychicMqttClient::connect()",
             "esp_err_t PsychicMqttClient::reconnect()",
             "void PsychicMqttClient::disconnect()",
+            "void PsychicMqttClient::softDisconnect(",
             "void PsychicMqttClient::forceStop()",
             "int PsychicMqttClient::subscribe(",
             "int PsychicMqttClient::publish(",
@@ -349,7 +365,7 @@ class MqttPublishAckTests(unittest.TestCase):
         )) + "\n".join(method(BRIDGE, signature) for signature in (
             "const char* MQTTBridge::tlsErrorStr(",
             "void MQTTBridge::formatSlotDiagReply(",
-        )) + MAIN
+        )) + main
         with tempfile.TemporaryDirectory(prefix="meshcore-mqtt-publish-ack-") as directory:
             fixture = Path(directory)
             (fixture / "Arduino.h").write_text(ARDUINO_HEADER, encoding="ascii")
@@ -373,6 +389,54 @@ class MqttPublishAckTests(unittest.TestCase):
                     result = subprocess.run([str(executable)], capture_output=True, text=True)
                     self.assertEqual(result.returncode, 0, result.stderr)
 
+    def test_production_publish_events_and_slot_diagnostics(self):
+        self.compile_run(MAIN)
+
+    def test_production_initialized_getter_tracks_sdk_creation_and_retained_stops(self):
+        self.compile_run(r'''
+int main() {
+  {
+    PsychicMqttClient client;
+    assert(!client.isInitialized() && !client.isStarted());
+    assert(client.connect() == ESP_ERR_INVALID_STATE);
+    assert(!client.isInitialized() && !client.isStarted());
+    client._mqtt_cfg.uri = "mqtt://broker";
+    client._mqtt_cfg.broker.address.uri = "mqtt://broker";
+    fail_init = true;
+    assert(client.connect() == ESP_ERR_NO_MEM);
+    assert(!client.isInitialized() && !client.isStarted());
+    fail_init = false;
+    register_result = ESP_ERR_INVALID_STATE;
+    assert(client.connect() == ESP_ERR_INVALID_STATE);
+    assert(!client.isInitialized() && !client.isStarted() && destroy_calls == 1);
+    register_result = ESP_OK;
+    start_result = ESP_ERR_NO_MEM;
+    assert(client.connect() == ESP_ERR_NO_MEM);
+    assert(client.isInitialized() && !client.isStarted());
+    const int retained_init_calls = init_calls;
+    start_result = ESP_OK;
+    assert(client.connect() == ESP_OK);
+    assert(client.isInitialized() && client.isStarted());
+    esp_mqtt_event_t connected{MQTT_EVENT_CONNECTED, 0, false};
+    sdk_event_handler(sdk_handler_args, "MQTT", connected.event_id, &connected);
+    client.disconnect();
+    assert(client.isInitialized() && !client.isStarted() && !client.connected());
+    assert(stop_calls == 1 && init_calls == retained_init_calls);
+    assert(client.connect() == ESP_OK);
+    assert(client.isInitialized() && client.isStarted() && init_calls == retained_init_calls);
+    sdk_event_handler(sdk_handler_args, "MQTT", connected.event_id, &connected);
+    client.softDisconnect();
+    assert(client.isInitialized() && client.isStarted() && !client.connected());
+    client.forceStop();
+    assert(client.isInitialized() && !client.isStarted());
+    assert(init_calls == retained_init_calls && destroy_calls == 1);
+  }
+  assert(destroy_calls == 2);
+  PsychicMqttClient fresh;
+  assert(!fresh.isInitialized() && !fresh.isStarted());
+}
+''')
+
 
 if __name__ == "__main__":
     unittest.main()