TAB in inferior-python-mode

[Stephen Berman]

Doing the following (in either current emacs-25 or master built from the
Savannah repository):

0. emacs -Q
1. M-x run-python
2. at the Python prompt type `for i in range(10):' then `RET', `TAB',
   `print i,', `RET'

results in this Python error:

IndentationError: expected an indented block

although the TAB in step 2 above visibly indents the line `print i,'.
If instead of `TAB' I type `SPC SPC SPC SPC' then after the final RET
the output is as expected:

0 1 2 3 4 5 6 7 8 9

It's not clear to me whether the above error indicates a bug in
python.el or there some setting I've overlooked that makes TAB work in
inferior-python-mode.  (In case it matter, this is with python 2.7.8., I
haven't tried with python3.)  I note that the definition of python-mode
has this line:

(set (make-local-variable 'indent-tabs-mode) nil)

which the definition of inferior-python-mode lacks; adding that line to
latter does make TAB work as expected.  But I'm not sure that is the
appropriate way to deal with this.  Does anyone here know?

Steve Berman