Demonstrate bug in System.sleep() - will sleep infinitely long with small values of `seconds`

SleepTest.cpp

#include "application.h"

STARTUP(System.enableFeature(FEATURE_RETAINED_MEMORY));

// if you want to change sleepTimeSeconds or reset sleepTimeSeconds back to maxSleepTimeSeconds, change the value of magicWordComparison and reflash application
const uint32_t magicWordComparison = 0xDEADBEEF;
const unsigned int maxSleepTimeSeconds = 10;

retained unsigned int sleepTimeSeconds = maxSleepTimeSeconds;
retained uint32_t magicWord = magicWordComparison;

void setup() {
    unsigned int currentSleepTimeSeconds;

    // simple check for valid retained memory
    if(magicWord != magicWordComparison) {
        magicWord = magicWordComparison;
        sleepTimeSeconds = maxSleepTimeSeconds;
    }

    currentSleepTimeSeconds = sleepTimeSeconds;
    if(--sleepTimeSeconds == 0)
        sleepTimeSeconds = maxSleepTimeSeconds;

    // wait for serial
    delay(10000);

    Serial.print("connected, going to sleep for ");
    Serial.print(currentSleepTimeSeconds);
    Serial.println(" seconds");

    System.sleep(SLEEP_MODE_DEEP, currentSleepTimeSeconds);
}

void loop() {

}