Should DEFINE_boolean() allow "None" as the default value?

[GoogleCodeExporter]

Currently, we can define a boolean flag with default value to None:

 FLAGS = gflags.FLAGS
 gflags.DEFINE_boolean("the_flag", None, "The flag.")

I'm not sure if this is expected or should it be allowed, since python-gflags 
project tries to mimic the C++ version of gflags as close as possible.  This is 
troublesome because user may be unaware that a boolean flag can fail both of 
the following assertions:

 assertTrue(FLAGS.the_flag)  # AssertionError: None is not True
 assertFalse(FLAGS.the_flag)  # AssertionError: None is not False

Original issue reported on code.google.com by linshu...@chromium.org on 4 Apr 2012 at 8:04

[GoogleCodeExporter]

Sorry for the late reply -- I'm not really the right person to speak to this 
for several reasons.  Besides not being the project maintainer anymore, I also 
don't know what the best thing to do is.  I agree it makes sense that a flag of 
type boolean should have type bool(), which None doesn't, but I don't know if 
it's reasonable to change the API at this point.

Original comment by csilv...@gmail.com on 20 Apr 2012 at 1:32

[gpshead]

python-gflags users should migrate to absl-py:
https://github.com/abseil/abseil-py
https://pypi.python.org/pypi/absl-py/

It is the modern version of this library.