Avoid AttributeError when calling start_wifi() after stop_bluetooth()

[glenrobertson]

stop_bluetooth() sets _uart to None, so when calling start_wifi(), the call to reset that tries to read self._uart raises a Value Error. Check that _uart is not None

[glenrobertson]

@tekktrik

[tekktrik]

Hi, unless there's a specific reason you tagged me, I'll mark this as ready for review and someone will take a look at the earliest opportunity :)

[glenrobertson]

@tekktrik thanks! Wasn't sure what the process was and saw you were a committer. Sorry to bother you

[tekktrik]

Taking a look at this, I think preventing the AttributeError is good, but the fix may be slightly more extensive since looking at this now, it seems like this will now just raise the RuntimeError if the Bluetooth is off at all. I think the fix is to also only attempt to check if startup_message is empty (and print it if debug is true) if self._uart is not None. Was that an issue you experienced with this modified code?

[glenrobertson]

@tekktrik thank you for taking an initial look and providing comments.
I updated what I have to only print the startup_message if it is set. I changed it slightly to avoid the negated logic, as I thought it might be more readable.

Since I got back to my project that uses this library, I realized an issue where toggling between bluetooth/wifi a few times, subsequent calls to start_bluetooth() can cause RuntimeError: Too many adapters, due to the subsequent calls to the constructor _bleio.Adapter(.....)

My use case is that I use bluetooth for pairing so an app can send the wifi credentials, and once they're received, it switches over to wifi to use them. If they are revoked for some reason, I needed to switch back to bluetooth to pair again.

I resolved this in 912f82f by avoiding reinitialization of _bleio_adapter. I tested it in my own code by using the following to start bluetooth after it had been started and stopped in the past:

if self.esp32._bleio_adapter is None:
    adapter = self.esp32.start_bluetooth()
    _bleio.set_adapter(adapter)
else:
    # avoid "RuntimeError: Too many adapters"
    self.esp32.reset(ESP32.BLUETOOTH)
    self.esp32._busy_cts.switch_to_input()
    self.esp32._gpio0_rts.switch_to_output()
    self.esp32._bleio_adapter.enabled = True
    adapter = self.esp32._bleio_adapter

Let me know what you think! Thanks in advance and apologies for the delay in responding.

[FoamyGuy]

I pushed a commit with code format / black changes to make the actions check happy.

This looks good to me now. If I'm following the logic correctly it now checks for existence of the bus or adapter internally rather than always initing a new one and shouldn't try to access a field that doesn't exist yet.

I tested this version successfully with this code intended to try to reproduce the issue described by switching back and forth from bluetooth to wifi and then back.

import time
import _bleio
from adafruit_airlift.esp32 import ESP32

esp32 = ESP32()
adapter = esp32.start_bluetooth(debug=True)
_bleio.set_adapter(adapter)  # pylint: disable=no-member

print(_bleio.adapter.address)

time.sleep(5)

esp32.stop_bluetooth()
print("bluetooth stopped")

time.sleep(3)

esp32.start_wifi(debug=True)
print("wifi started")

time.sleep(3)

esp32.stop_wifi()
print("wifi stopped")

adapter = esp32.start_bluetooth(debug=True)
_bleio.set_adapter(adapter)  # pylint: disable=no-member

print(_bleio.adapter.address)

With the version from this PR the code seems to run and function as intended.

[glenrobertson]

@FoamyGuy thank you for helping with this and merging! And thank you @tekktrik for taking a look and providing comments too.