Assignment Semantics Issue

[Lotharyx]

With intrinsic type T, given:

EEPROMStorage<T> first_thing(0, 0);
EEPROMStorage<T> second_thing((sizeof(T) + 1), 0);

Code such as the following:

...
second_thing = first_thing;
...

does not result in the value in first_thing being copied into second_thing, which misled me (an experienced coder) and probably would be very misleading to a novice (common among Arduino users). It in fact appears to cause the checksum of second_thing to become invalid, as evidenced by the constructor reinitializing the default value on the next boot.

Using a temporary variable yields the expected result, e.g.,

...
T temp = first_thing;
second_thing = temp;
...

I suggest that EEPROMStorage<T>::operator=(const EEPROMStorage & rhs) and EEPROMStorage<T>::operator=(const T& rhs) should be equivalent.

[Lotharyx]

Here's an MCRE.

#include <EEPROM-Storage.h>

EEPROMStorage<int> a(0, 0);
EEPROMStorage<int> b(sizeof(int) + 1, 0);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Values at startup: ");
  Serial.print("a: "); Serial.println(a);
  Serial.print("b: "); Serial.println(b);
}

void loop() {
  // put your main code here, to run repeatedly:
  a++;
  if(a % 5 == 0) {
    b = a;
    Serial.println("Assigned a to b!");
    Serial.println("New values: ");
    Serial.print("a: "); Serial.println(a);
    Serial.print("b: "); Serial.println(b);
    Serial.println("Reset the arduino now.");
    while(true) delay(100);
  }
}

Actual output:

Values at startup: 
a: 0
b: 0
Assigned a to b!
New values: 
a: 5
b: 5
Reset the arduino now.
Values at startup: 
a: 5
b: 0
Assigned a to b!
New values: 
a: 10
b: 10
Reset the arduino now.

Notice that b is reinitialized to 0.

Expected output:

Values at startup: 
a: 0
b: 0
Assigned a to b!
New values: 
a: 5
b: 5
Reset the arduino now.
Values at startup: 
a: 5
b: 5
Assigned a to b!
New values: 
a: 10
b: 10
Reset the arduino now.