Using adapter other than 'hci0' gives error during discovery

[yggdr]

• bleak version:
  0.4.2 + workaround patch from Unhandled error in discovery.py #69 (+ a few prints for debugging, so line numbers might be off by 1 or 2)
• Python version:
  3.7.3
• Operating System:
  Ubuntu 19.04 / Linux 5.0.0-16-generic #17

Description

Using an adapter other than 'hci0' does get set in the BleakClientBlueZDBus instance, but not propagated to all called functions, like e.g. backends.bluezdbus.discovery.discover

What I Did

Create an instance with a non-default device and have it try to connect. Very stripped down version of our code:

from bleak import BleakClient
import sys
import asyncio

class MyInternalStuff:
    def __init__(self, ble_addr, *, adapter="hci0", loop):
        self._adapter = adapter
        self._dev = BleakClient(ble_addr, device=self._adapter, timeout=35)
    async def __aenter__(self):
        await self._dev.__aenter__()
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        await self._dev.__aexit__(exc_type, exc_val, exc_tb)

async def main(loop):
    async with MyInternalStuff(ble_addr="12:34:56:78:90:ab", adapter='hci1', loop=loop):
        pass

if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    sys.exit(loop.run_until_complete(main(loop)))

gives

Traceback (most recent call last):
  File "bug.py", line 25, in <module>
    sys.exit(loop.run_until_complete(main(loop)))
  File "/usr/lib/python3.7/asyncio/base_events.py", line 584, in run_until_complete
    return future.result()
  File "bug.py", line 19, in main
    async with MyInternalStuff(ble_addr="12:34:56:78:90:ab", adapter='hci1', loop=loop):
  File "bug.py", line 12, in __aenter__
    await self._dev.__aenter__()
  File "/home/yggdrasil/.virtualenvs/svhsystemtests/lib/python3.7/site-packages/bleak/backends/client.py", line 41, in __aenter__
    await self.connect()
  File "/home/yggdrasil/.virtualenvs/svhsystemtests/lib/python3.7/site-packages/bleak/backends/bluezdbus/client.py", line 65, in connect
    await discover(timeout=0.1, loop=self.loop)
  File "/home/yggdrasil/.virtualenvs/svhsystemtests/lib/python3.7/site-packages/bleak/backends/bluezdbus/discovery.py", line 143, in discover
    adapter_path, interface = _filter_on_adapter(objects, device)
  File "/home/yggdrasil/.virtualenvs/svhsystemtests/lib/python3.7/site-packages/bleak/backends/bluezdbus/discovery.py", line 26, in _filter_on_adapter
    raise Exception("Bluetooth adapter not found")
Exception: Bluetooth adapter not found

Patching backends/bluezdbus/client.py:65 like so:
await discover(timeout=0.1, device=self.device, loop=self.loop)
fixes this particular instance, but there might be more places this is missing.

[hbldh]

This is definitely a an oversight, and I will remedy this bug in version 0.4.3, which will be released shortly.

[hbldh]

Made necessary modifications, tested it with a second adapter in Ubuntu 18.04 and released 0.4.3.
Thank you for reporting this and reopen if you find further problems with this.