Fixed issue where esp32 won't reconnect to WiFi AP if the AP was restarted. (#7512)

* Fixed issue where esp32 won't reconnect to WiFi AP if the AP was restarted

* Added the autoReconnect condition and removed the reconnect reason

* Chenges on the WiFi reconnection and added new example

* Added new line at the end

* Changes reverted with some minor changes. New example remained

* Changes reverted and sync
Co-authored-by: Npedro.minatel <pedro.minatel@espressif.com>

libraries/WiFi/examples/WiFiClientConnect/README.md

+# WiFiClientConnect Example
+
+This example demonstrates how to connect to the WiFi and manage the status and disconnection from STA.
+
+# Supported Targets
+
+Currently, this example supports the following targets.
+
+| Supported Targets | ESP32 | ESP32-S2 | ESP32-C3 |
+| ----------------- | ----- | -------- | -------- |
+
+## How to Use Example
+
+* How to install the Arduino IDE: [Install Arduino IDE](https://github.com/espressif/arduino-esp32/tree/master/docs/arduino-ide).
+
+#### Using Arduino IDE
+
+* Before Compile/Verify, select the correct board: `Tools -> Board`.
+* Select the COM port: `Tools -> Port: xxx` where the `xxx` is the detected COM port.
+
+#### Using Platform IO
+
+* Select the COM port: `Devices` or set the `upload_port`` option on the `platformio.ini` file.
+
+## Example/Log Output
+
+```
+[WiFi] Connecting to MyWiFiNetwork
+[    66][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 0 - WIFI_READY
+[   150][V][WiFiGeneric.cpp:338] _arduino_event_cb(): STA Started
+[   151][V][WiFiGeneric.cpp:97] set_esp_interface_ip(): Configuring Station static IP: 0.0.0.0, MASK: 0.0.0.0, GW: 0.0.0.0
+[   151][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 2 - STA_START
+[WiFi] WiFi is disconnected
+[   234][V][WiFiGeneric.cpp:353] _arduino_event_cb(): STA Connected: SSID: MyWiFiNetwork, BSSID: xx:xx:xx:xx:xx:xx, Channel: 8, Auth: WPA2_PSK
+[   235][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 4 - STA_CONNECTED
+[   560][V][WiFiGeneric.cpp:367] _arduino_event_cb(): STA Got New IP:192.168.68.114
+[   561][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 7 - STA_GOT_IP
+[   564][D][WiFiGeneric.cpp:1004] _eventCallback(): STA IP: 192.168.68.114, MASK: 255.255.255.0, GW: 192.168.68.1
+[WiFi] WiFi is connected!
+[WiFi] IP address: 192.168.68.114
+[WiFi] Disconnecting from WiFi!
+[  2633][V][WiFiGeneric.cpp:360] _arduino_event_cb(): STA Disconnected: SSID: MyWiFiNetwork, BSSID: xx:xx:xx:xx:xx:xx, Reason: 8
+[  2634][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 5 - STA_DISCONNECTED
+[  2635][V][WiFiGeneric.cpp:341] _arduino_event_cb(): STA Stopped
+[  2641][W][WiFiGeneric.cpp:953] _eventCallback(): Reason: 8 - ASSOC_LEAVE
+[  2654][D][WiFiGeneric.cpp:975] _eventCallback(): WiFi the station is disconnected
+[  2661][D][WiFiGeneric.cpp:929] _eventCallback(): Arduino Event: 3 - STA_STOP
+[WiFi] Disconnected from WiFi!
+...
+```
+
+## Troubleshooting
+
+***Important: Be sure you're using a good quality USB cable that has enough power for your project.***
+
+* **Programming Fail:** If the programming/flash procedure fails, try to reduce the serial connection speed.
+* **COM port not detected:** Check the USB cable connection and the USB to Serial driver installation.
+
+If the error persists, you can ask for help at the official [ESP32 forum](https://esp32.com) or see [Contribute](#contribute).
+
+## Contribute
+
+To know how to contribute to this project, see [How to contribute.](https://github.com/espressif/arduino-esp32/blob/master/CONTRIBUTING.rst)
+
+If you have any **feedback** or **issue** to report on this example/library, please open an issue or fix it by creating a new PR. Contributions are more than welcome!
+
+Before creating a new issue, be sure to try Troubleshooting and check if the same issue was already created by someone else.
+
+## Resources
+
+* Arduino-ESP32 Official Repository: [espressif/arduino-esp32](https://github.com/espressif/arduino-esp32)
+* ESP32 Datasheet: [Link to datasheet](https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf)
+* ESP32-S2 Datasheet: [Link to datasheet](https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf)
+* ESP32-C3 Datasheet: [Link to datasheet](https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf)
+* Official ESP-IDF documentation: [ESP-IDF](https://idf.espressif.com)

libraries/WiFi/examples/WiFiClientConnect/WiFiClientConnect.ino

+/* Wi-Fi STA Connect and Disconnect Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+   
+*/
+#include <WiFi.h>
+
+const char* ssid     = "your-ssid";
+const char* password = "your-password";
+
+int btnGPIO = 0;
+int btnState = false;
+
+void setup()
+{
+    Serial.begin(115200);
+    delay(10);
+
+    // Set GPIO0 Boot button as input
+    pinMode(btnGPIO, INPUT);
+
+    // We start by connecting to a WiFi network
+    // To debug, please enable Core Debug Level to Verbose
+
+    Serial.println();
+    Serial.print("[WiFi] Connecting to ");
+    Serial.println(ssid);
+
+    WiFi.begin(ssid, password);
+// Auto reconnect is set true as default
+// To set auto connect off, use the following function
+//    WiFi.setAutoReconnect(false);
+
+    // Will try for about 10 seconds (20x 500ms)
+    int tryDelay = 500;
+    int numberOfTries = 20;
+
+    // Wait for the WiFi event
+    while (true) {
+        
+        switch(WiFi.status()) {
+          case WL_NO_SSID_AVAIL:
+            Serial.println("[WiFi] SSID not found");
+            break;
+          case WL_CONNECT_FAILED:
+            Serial.print("[WiFi] Failed - WiFi not connected! Reason: ");
+            return;
+            break;
+          case WL_CONNECTION_LOST:
+            Serial.println("[WiFi] Connection was lost");
+            break;
+          case WL_SCAN_COMPLETED:
+            Serial.println("[WiFi] Scan is completed");
+            break;
+          case WL_DISCONNECTED:
+            Serial.println("[WiFi] WiFi is disconnected");
+            break;
+          case WL_CONNECTED:
+            Serial.println("[WiFi] WiFi is connected!");
+            Serial.print("[WiFi] IP address: ");
+            Serial.println(WiFi.localIP());
+            return;
+            break;
+          default:
+            Serial.print("[WiFi] WiFi Status: ");
+            Serial.println(WiFi.status());
+            break;
+        }
+        delay(tryDelay);
+        
+        if(numberOfTries <= 0){
+          Serial.print("[WiFi] Failed to connect to WiFi!");
+          // Use disconnect function to force stop trying to connect
+          WiFi.disconnect();
+          return;
+        } else {
+          numberOfTries--;
+        }
+    }
+}
+
+void loop()
+{
+    // Read the button state
+    btnState = digitalRead(btnGPIO);
+    
+    if (btnState == LOW) {
+      // Disconnect from WiFi
+      Serial.println("[WiFi] Disconnecting from WiFi!");
+      // This function will disconnect and turn off the WiFi (NVS WiFi data is kept)
+      if(WiFi.disconnect(true, false)){
+        Serial.println("[WiFi] Disconnected from WiFi!");
+      }
+      delay(1000);
+    }
+}

libraries/WiFi/src/WiFiGeneric.cpp

@@ -1070,6 +1070,7 @@ esp_err_t WiFiGenericClass::_eventCallback(arduino_event_t *event)
 
 bool WiFiGenericClass::_isReconnectableReason(uint8_t reason) {
     switch(reason) {
+        case WIFI_REASON_UNSPECIFIED:
         //Timeouts (retry)
         case WIFI_REASON_AUTH_EXPIRE:
         case WIFI_REASON_4WAY_HANDSHAKE_TIMEOUT: