fix(ppp): Fix PPP.end() causing exception (#11987)

* fix(ppp): Fix PPP.end() causing exception

* fix(periman): Return NULL if deinit callback is cleared

Author: me-no-dev

cores/esp32/esp32-hal-periman.c

@@ -236,11 +236,30 @@ bool perimanSetBusDeinit(peripheral_bus_type_t type, peripheral_bus_deinit_cb_t
   return true;
 }
 
+// This no-op callback is used by perimanClearBusDeinit() to effectively disable bus deinit functionality
+// without setting the callback to NULL, which would cause errors in perimanSetPinBus() at line 146.
+static bool empty_bus_deinit_cb(void *bus) {
+  return true;
+}
+
+bool perimanClearBusDeinit(peripheral_bus_type_t type) {
+  if (type >= ESP32_BUS_TYPE_MAX || type == ESP32_BUS_TYPE_INIT) {
+    log_e("Invalid type: %s (%u)", perimanGetTypeName(type), (unsigned int)type);
+    return false;
+  }
+  deinit_functions[type] = empty_bus_deinit_cb;
+  log_v("Deinit function for type %s (%u) cleared", perimanGetTypeName(type), (unsigned int)type);
+  return true;
+}
+
 peripheral_bus_deinit_cb_t perimanGetBusDeinit(peripheral_bus_type_t type) {
   if (type >= ESP32_BUS_TYPE_MAX || type == ESP32_BUS_TYPE_INIT) {
     log_e("Invalid type: %s (%u)", perimanGetTypeName(type), (unsigned int)type);
     return NULL;
   }
+  if (deinit_functions[type] == empty_bus_deinit_cb) {
+    return NULL;
+  }
   return deinit_functions[type];
 }
 

cores/esp32/esp32-hal-periman.h

@@ -134,6 +134,9 @@ int8_t perimanGetPinBusChannel(uint8_t pin);
 // Sets the peripheral destructor callback. Used to destroy bus when pin is assigned another function
 bool perimanSetBusDeinit(peripheral_bus_type_t type, peripheral_bus_deinit_cb_t cb);
 
+// Clears the peripheral destructor callback
+bool perimanClearBusDeinit(peripheral_bus_type_t type);
+
 // Get the peripheral destructor callback. It allows changing/restoring the peripheral pin function detaching, if necessary
 // returns NULL if none is set
 peripheral_bus_deinit_cb_t perimanGetBusDeinit(peripheral_bus_type_t type);

libraries/PPP/src/PPP.cpp

@@ -394,6 +394,11 @@ void PPPClass::end(void) {
     Network.postEvent(&arduino_event);
   }
 
+  if (_dce != NULL) {
+    esp_modem_destroy(_dce);
+    _dce = NULL;
+  }
+
   destroyNetif();
 
   if (_ppp_ev_instance != NULL) {
@@ -406,10 +411,10 @@ void PPPClass::end(void) {
   Network.removeEvent(_ppp_event_handle);
   _ppp_event_handle = 0;
 
-  if (_dce != NULL) {
-    esp_modem_destroy(_dce);
-    _dce = NULL;
-  }
+  perimanClearBusDeinit(ESP32_BUS_TYPE_PPP_TX);
+  perimanClearBusDeinit(ESP32_BUS_TYPE_PPP_RX);
+  perimanClearBusDeinit(ESP32_BUS_TYPE_PPP_RTS);
+  perimanClearBusDeinit(ESP32_BUS_TYPE_PPP_CTS);
 
   int8_t pin = -1;
   if (_pin_tx != -1) {
@@ -438,6 +443,11 @@ void PPPClass::end(void) {
     perimanClearPinBus(pin);
   }
 
+  perimanSetBusDeinit(ESP32_BUS_TYPE_PPP_TX, PPPClass::pppDetachBus);
+  perimanSetBusDeinit(ESP32_BUS_TYPE_PPP_RX, PPPClass::pppDetachBus);
+  perimanSetBusDeinit(ESP32_BUS_TYPE_PPP_RTS, PPPClass::pppDetachBus);
+  perimanSetBusDeinit(ESP32_BUS_TYPE_PPP_CTS, PPPClass::pppDetachBus);
+
   _mode = ESP_MODEM_MODE_COMMAND;
 }