autopep8 Doesn't seem to support tabs properly.

I am modifying autopep8 and pycodestyle to work with another programming language that is very similar to python. However, the style guide for this other language is that it should use tabs.

I modified pycodestyle to use tabs by modifying "indent_char" to a '\t'.

In autopep8, I saw the lines:

 if indent_char != '\t' else (DEFAULT_INDENT_SIZE,
                                     2 * DEFAULT_INDENT_SIZE)
    )

And thought this meant it would read the indent character from pycodestyle.

However, upon execution, it always completely overwrites the tabs with spaces. This issue https://github.com/jorgenschaefer/elpy/issues/680 seems to suggest it should work. A similar issue is already reported here https://github.com/hhatto/autopep8/issues/207 where they suggest using --ignore=E101,E111 but this disables all reindentation (ie an incorrectly indented line is not fixed).

I struggle to find the part of the code that actually does the reindentation. I would have expected it to be the "Reindenter" class, but it seems that by the time the lines are passed in there, they're already space-ified.

I'm aware this is outside the normal use-case of autopep8, but was wondering if one of the devs could give me some guidance on how to make it support the indentation with tabs rather than spaces.