release lock only if acquired

[spacemanspiff2007]

If connection fails calling __aexit__ will result in an Lock-exception.
This small check prevents that

[codecov]

Codecov Report

Patch coverage: 100.0% and no project coverage change.

Comparison is base (5f0c94c) 84.7% compared to head (971afe2) 84.7%.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #249   +/-   ##
=====================================
  Coverage   84.7%   84.7%           
=====================================
  Files          4       4           
  Lines        472     473    +1     
  Branches      87      88    +1     
=====================================
+ Hits         400     401    +1     
  Misses        45      45           
  Partials      27      27           

Files Changed	Coverage Δ
aiomqtt/client.py	83.4% <100.0%> (+<0.1%)	⬆️

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[empicano]

Good catch, and thank you for the PR with a fix! 😊

I wasn't sure if we should allow calling __aexit__ without a prior __aenter__ (or an unsuccessful __aenter__ in this case).

I tested open() and contextlib.ExitStack(), which don't throw exceptions when calling __exit__ without __enter__. PEP343 also states that "[...] __exit__() methods should avoid raising errors unless they have actually failed." 👍

Could you add a test case for this? (Probably sufficient to test if we can call __aexit__ without __aenter__.) Then we'll merge it straight away 🙂

[spacemanspiff2007]

Like this?

I wasn't sure if we should allow calling __aexit__ without a prior __aenter__ (or an unsuccessful __aenter__ in this case).

Imho it only makes sense, there is nothing to gain if it raises an error.
Also manually calling both methods is the only way to use this library if using a context manager is not an option.

[vvanglro]

Using a context manager is the only recommended method and the main direction of subsequent maintenance, because the removal of the connect and disconnect methods is already planned #247.

If connection fails calling __aexit__ will result in an Lock-exception. This small check prevents that

This does not happen if you use a context manager.

Based on PEP343, this PR is great.

[spacemanspiff2007]

Using a context manager is the only recommended method and the main direction of subsequent maintenance, because the removal of the connect and disconnect methods is already planned #247.

I'm aware of that and the docs make this clear.
However I have a central connection manager in my application that manages multiple connection lifecycles.
Using the context manager would mean a complete refactor of the way the application handles connections and loosing features that would have to be implemented in another way..
Instead I just call the context manager methods , e.g. aenter or already with a local fix aexit and everything works as expected 🤷
If you have a good idea how I can have feature parity with a context manager I'm happy to hear it. 👍

[empicano]

For your use case, using __aenter__ and __aexit__ directly sounds like a great escape hatch 👍

The test looks good. Thank you for your contribution to aiomqtt! 😎