EEPROM.length() returns zero by default?

[aphelps]

Is there a design reason that EEPROM.length() is returning the value of _user_defined_size rather than _size? It would appear that the _user_defined_size is only set by the constructors and is never used, whereas the size specified to EEPROM.begin() is the one that all other EEPROM functions use to limit the writable area.

To be consistent with the Arduino EEPROM API for AVRs (where EEPROM.length() returns the actual EEPROM limit for the chip), it would seem to be more logical for EEPROM.length() to either return the size specified in EEPROM.begin() or to return SPI_FLASH_SEC_SIZE when _user_defined_size hasn't been set.

I'd be happy to submit a patch if appropriate.

For context, I'm working on converting some personal library code to work on my existing boards and a new one based on the Esp32, and ran into this probably while doing so.

[lbernstone]

It is certainly worth discussion, as the current result seems overly simplistic. I haven't really used _user_defined_size. Are there situations where it would not just be length = _user_defined_size ? _user_defined_size : _size?

[aphelps]

Its not at all clear to me what the intent of _user_defined_size is. The only size used for limits on the IO in this class is the one passed into EEPROM.begin(size_t size),_user_defined_size only appears in the initializer and EEPROM.length(). ie in the current code:

void EEPROMClass::write(int address, uint8_t value) {
  if (address < 0 || (size_t)address >= _size)
    return;
  if (!_data)
    return;

So as I think it would just need to be:

uint16_t EEPROMClass::length ()
{
  return _size;
}

_user_defined_size seems to me like something that was intended by the original author to be used for something that was never implemented.

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