Iterator zombie won't die :) about pyfirmata HOT 3 CLOSED

Hi, this bug is due to Board.exit() never getting called automatically from Board.__del__() as long as there is a Iterator thread running.
This happens because the Iterator thread keeps a -circular- reference to the Board! So if you try to stop Python (keyboard interruption or any exception...) the main thread dies but Python does not call Board.__del__() yet and instead keeps waiting for the Iterator thread to stop... which never happens.
So, unless you manually call Board.exit() under any situation ("try:... finally: board.exit()") is highly probable that your Iterator will become a zombie.

I created a new pull request (#45) with some commits that fix this problem by implementing the support for the Python "with" statement, so you can do something like this:

>> from pyfirmata import Arduino, util
>> board = Arduino('/dev/tty...')
>> with board:
>>     board.analog[0].enable_reporting()
>>     board.analog[0].read()

and it will take care of creating the Iterator thread at the beginning of the with block and stopping it (automatically calling board.exit()) at the end of the block even when an exception happens. So it would be a shorter (and cooler ;) ) equivalent to:

>> from pyfirmata import Arduino, util
>> board = Arduino('/dev/tty...')
>> it = util.Iterator(board)
>> it.start()
>> try:
>>     board.analog[0].enable_reporting()
>>     board.analog[0].read()
>> finally:
>>     board.exit()
>>     it = None

I hope @tino likes the pull request and merges it soon :)

from pyfirmata.

Hi, I think I've experienced this as well before, but I am not really familiar with all ins and outs of threads. Could you make a pull request out of this?

from pyfirmata.

Fix with #44

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