esp_spp_write() fails in a quite spectacular way when len is 0 (IDFGH-8523)

[Delzye]

Is your feature request related to a problem?

I had a mistake in my code which prompted the len for my buffer to be overwritten with 0 sometimes.
I realise that sending nothing (len = 0) should not be done and I could have written a check for that myself, but making esp_spp_write in a different way would be appreciated.

Currently. the message gets enqueued in osi_thread_post(), but when retrieving it, at some point in another call of fixed_queue_enqueue(), the assertion "data != NULL" gets triggered (I assume the len was used to copy the data somewhere, which failed if len=0, I did not research that in any more detail).

Describe the solution you'd like.

just returning from esp_spp_write() if len=0 would be nice.

Describe alternatives you've considered.

Writing the check myself, but since that would be needed with every esp_spp_write anyway, integrating it directly would be nicer (and you don't spend hours debugging a pretty obscure error message...).

Additional context.

No response