[Bazel] Fix mobile-install for python2

[ThomasCJY]

Background
Fix issue introduced by 1049fe8
It turns out the queue module name is inconsistent across different python versions. We found that:

• On some macos system:
  • python2 contains both queue and Queue module. All python2 contains Queue module
  • python3 only contains queue module
• On some Linux system
  • python2 contains only Queue module.
  • python3 only contains queue module

Therefore, some developers are seeing ImportError: No module named queue errors locally on linux machine after using mobile-install.

Change
Import correct Queue module instead

Test
Local test pass

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[ThomasCJY]

Should we use

try:
    import Queue from Queue
except ImportError:
    import queue as Queue 

here to support both python 2 and 3?

[arunkumar9t2]

try:
    from Queue import Queue
except ImportError:
    import queue as Queue 

This is the syntax that worked when python 2 is used.

[odracirnumira]

@ThomasCJY can you change the code to the alternative suggested by @arunkumar9t2 ? That'll make this work in both Pyton2 and 3.

[ThomasCJY]

updated @arunkumar9t2 @odracirnumira ptal

[odracirnumira]

The change looks reasonable to me. Unfortunately I lack the necessary permissions to stamp the diff. I think @ahumesky is the right person to loop in here?

[nkoroste]

Any updates on this? pretty trivial change...

[ahumesky]

I've imported this change internally, but our linters are pretty unhappy about imports "not at top of file". We seem to be doing this in other places so I think I can work around it.

[ahumesky]

looks like this is causing the //tools/android:build_incremental_dexmanifest_test test to fail:

tools/android/build_incremental_dexmanifest.py", line 55, in __init__
    self.queue = Queue()
TypeError: 'module' object is not callable

(and also causing 2 internal tests to fail with the same error)

Looks like this is because the original code from queue import Queue imports the Queue class from the module queue, whereas in the except block, the code import queue as Queue imports the module with the name "Queue".

Are these the 3 scenarios?

1. from queue import Queue (original. Queue class in queue module)
2. from Queue import Queue (Queue class is is Queue module)
3. import Queue (import just module, module is callable to produce Queue object)

At least on my Linux machine, scenario 3 doesn't seem to work. There appears to be both queue and Queue in python2, just queue in python3, and the module isn't callable in any of the cases. I think queue in python2 is from a compatibility package:

>>> print(queue.__file__)
/usr/lib/python2.7/dist-packages/queue/__init__.pyc

So unless something is different on macos, seems this change should be:

try:
  # python2 without compatibility package
  from Queue import Queue
except ImportError:
  # python3
  from queue import Queue

[ThomasCJY]

@ahumesky yeah you are right. It's a bit confusing but according to the python doc:

python 2 uses Queue module name and the creation of object is Queue.Queue()
https://docs.python.org/2.7/library/queue.html

python 3 uses queue module name and the creation of object is queue.Queue()
https://docs.python.org/3.8/library/queue.html

so the import syntax should be

try:
  # python2 without compatibility package
  from Queue import Queue
except ImportError:
  # python3
  from queue import Queue

[ThomasCJY]

@ahumesky is this good to go?