[WiFi] scanComplete always returns -1 after async scanNetworks is invoked

[toomasz]

Hardware:

Board: ESP32 Dev Module
Core Installation/update date: 10/aug/2017
IDE name: Arduino IDE
Flash Frequency: 80Mhz
Upload Speed: 921600

Description:

scanComplete always returns -1 after async scanNetworks is invoked, even though wifi callback with SCAN_DONE event is received

It seems like duplicate of #354

Sketch:

#include <WiFi.h>

void setup()
{
Serial.begin(115200);
WiFi.mode(WIFI_STA);
WiFi.disconnect();
Serial.println("setup completed");
}

void loop()
{
delay(500);
int8_t n = WiFi.scanComplete();
Serial.println("scanComplete: " + String(n));
if(n == -2)
{
Serial.println("Scan networks");
WiFi.scanNetworks(true);
}
if(n == -1)
{
Serial.println("Scan in progress...");
}

if(n < 0)
{
return;
}

Serial.println("networks found: " + String(n));
for (int i = 0; i < n; ++i)
{
Serial.println( String(n) + ": " + String(WiFi.SSID(i)));
}

delay(1000);
}

Debug Messages:

ts Jun 8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0010,len:4
load:0x3fff0014,len:708
load:0x40078000,len:0
load:0x40078000,len:12168
entry 0x40078a68
setup completed
[D][WiFiGeneric.cpp:182] _eventCallback(): Event: 2 - STA_START
scanComplete: -2
Scan networks
[D][WiFiGeneric.cpp:182] _eventCallback(): Event: 1 - SCAN_DONE
scanComplete: -1
Scan in progress...
scanComplete: -1
Scan in progress...
scanComplete: -1
Scan in progress...
scanComplete: -1
Scan in progress...

[toomasz]

This issue is caused by passing block = true in async mode in line:

arduino-esp32/libraries/WiFi/src/WiFiScan.cpp

Line 82 in 7e5b278

if(esp_wifi_scan_start(&config, WiFiScanClass::_scanAsync) == ESP_OK) {

I believe this line should be changed to:
if(esp_wifi_scan_start(&config, false) == ESP_OK) {