From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Goaziou <mail@nicolasgoaziou.fr>
Subject: Re: Bug: Tangling python code results in mixed tabs and spaces,
 incomaptible with python3 [9.1.4 (9.1.4-dist @
 /home/ehere/emacs-scripts/org-9.1.4/lisp/)]
Date: Thu, 21 Dec 2017 14:56:04 +0100
Message-ID: <873744kwwb.fsf@nicolasgoaziou.fr>
References: <20171220182448.6ltm4m4emmt7ftxv@knuspertop>
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In-Reply-To: <20171220182448.6ltm4m4emmt7ftxv@knuspertop> (Edmund Christian
	Herenz's message of "Wed, 20 Dec 2017 19:24:48 +0100")
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To: Edmund Christian Herenz <christian.herenz@astro.su.se>
Cc: emacs-orgmode@gnu.org

Hello,

Edmund Christian Herenz <christian.herenz@astro.su.se> writes:

> The following python code uses only whitespaces for the different
> indentdation levels:
>
> a_list = ['elem1',
>           'elem2',
>           'elem3']
>
> for elem in a_list:
>     print(elem)
>     for char in elem:
>         print char
>
> I enter this code into a SRC block with
>
> #+BEGIN_SRC python :tangle blank_test.py
>
> #+END_SRC
>
> by pressing C-' inside the block (which opens the editing buffer
> python-mode).  Then I press C-' again, after which I tangle the code
> to blank_test.py by pressing C-u C-c C-v C-t.  The resulting file
> blank_test.py will contain a mix of tabs and spaces for the different
> intendation levels.  (I checked this with whitespace.el).
>
> Above behaviour is a bug, since Python3 forbids mixing of spaces and
> tabs. (Python2 is more relaxed about mixing of tabs and spaces). Thus,
> the above code, syntactical correctly entered into an OrgSrc buffer,
> will result in code that can not be run in python3 when tangled from
> an org-mode file.

Have you tried "-i" switch for the block, i.e.,

  #+BEGIN_SRC python -i :tangle blank_test.py


Regards, 

-- 
Nicolas Goaziou