get_chromcasts() copy device list before iteration

[Shane-Wiseman-Bose]

resolves #488 by making a copy of device list returned from discovery before iterating over list.

[Shane-Wiseman-Bose]

There is another option of making the copy on the iterable return from discover_chromecasts() which can protect all calls. I figured to lessen the scope for ease of review and to reflect my knowledge depth of the repos.

pychromecast/pychromecast/discovery.py

Line 526 in 48a1d59

return (browser.devices.values(), browser)

[Shane-Wiseman-Bose]

Example of issue.

>>> a = {"a": 1, "b": 2}
>>> b = a.values()
>>> for i in b:
...     if "a" in a:
...             del(a["a"])
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: dictionary changed size during iteration

Example of Fix

>>> a = {"a": 1, "b": 2}
>>> b = a.values()
>>> for i in list(b):
...     if "a" in a:
...             del(a["a"])
...
>>>

[emontnemery]

There is another option of making the copy on the iterable return from discover_chromecasts() which can protect all calls

That's a better option, can you update the PR to do that instead?

[Shane-Wiseman-Bose]

moved the list copy to discovery.py calls. A user can still access the mutable device object by referencing the browser attribute browser.devices

[Shane-Wiseman-Bose]

@emontnemery is there anything else pending on this?

[emontnemery]

@Shane-Wiseman-Bose nothing else, thanks for the PR! 👍