how to reduce bugs due to incorrect indentation

[Asaf Las]

On Friday, February 7, 2014 12:30:17 AM UTC+2, Chris Angelico wrote:
> On Fri, Feb 7, 2014 at 9:09 AM, Larry Martell <lar... at gmail.com> wrote:
> 
> > The Tab key is not evil, it's the tab character (Ctrl-I). I have been
> > bitten by this many time when I had to work on a program written by
> > another. They had their tab stops set at 5 or 6, mine is set at 4, or
> > they did not have expandtab set, but I did. So you get either a script
> > that looks misaligned, but works, or one that does not look misaligned
> > but doesn't work. When I have to pick up someone else's script the
> > first thing I do is replace the tabs with spaces.
> 
> All you've proven is that *mixing* spaces and tabs is evil. It's like
> arguing that oil is evil because, when you mix it with water, weird
> stuff happens. But that doesn't mean I want to fry my bacon in water.
> Mmm, bacon.
> Sorry. I'm back now. Ahem. Arguably, a better fix is to replace spaces
> with tabs, because they're more obvious. But mainly, just be
> consistent. Whatever one file uses, it uses exclusively. It'd be
> pretty easy to create a git commit hook that checks files for leading
> indentation and rejects the commit if it's mismatched; I would guess
> the same is true in Mercurial.
> 
> But none of this would solve the OP's original issue. Whether it's a
> tab or spaces, unexpectedly indenting a line of code is a problem.
> It's no different from accidentally hitting Ctrl-T in SciTE and
> reordering two lines, when one line depends on the other. It's a bug.
> So you look at your commits before you make them (to give yourself a
> chance to catch it quickly), and you make sure you can always look
> back over your commits (in case you didn't catch it quickly). Much
> better than blaming the characters involved. Poor innocent U+0009.
> ChrisA

pep8 pushed \t to dark side in Python. 

though it is better that spaces sometimes. let say someone's indented code
with 2 spaces and user is comfortable with 4. if \t then it is done by 
editor's conf without touching code.

/Asaf