[Python-Dev] Avoiding whitespace conflicts (was: I am now lost - committed, pulled, merged, what is "collapse"?)

[Ben Finney]

Ned Deily <nad at acm.org> writes:

> As a side note, if you are prone to accidentally adding extra
> whitespace (like I am), you can add the whitespace check hook into
> your local copy of Mercurial so that you will be warned about
> whitespace problems immediately when you commit things to your local
> repos rather than later when you try to push them up to the python.org
> repo.

Even earlier that the attempt to commit, one can configure the text
editor to show whitespace in order to be aware of it at the point where
it's easiest to change:

    Emacs:

        M-x whitespace-mode RET

    Vim:

        :set list listchars=trail:·,tab:»·

Or, instead of all whitespace, highlight trailing whitespace as an
error:

    Emacs:

        M-: (setq show-trailing-whitespace t) RET

    Vim:

        :set list listchars=trail:·,tab:»·
        :highlight SpecialKey ctermfg=Yellow ctermbg=Red

Of course, any Python programmer hoping to comply with PEP 8 is best
advised to never insert a U+0009 HORIZONTAL TAB character:

    Emacs:

        M-: (setq indent-tabs-mode nil) RET

    Vim:

        :set expandtabs

One can even tell the editor to remove all the trailing whitespace:

    Emacs:

        M-x delete-trailing-whitespace RET

    Vim:

        :%s:\s\+$::

More:

    <URL:http://www.emacswiki.org/emacs/WhiteSpace>
    <URL:http://stackoverflow.com/questions/3165503/emacs-global-configuration-of-tabs>

    <URL:http://vim.wikia.com/wiki/Highlight_unwanted_spaces>
    <URL:http://vim.wikia.com/wiki/Remove_unwanted_spaces>
    <URL:http://stackoverflow.com/questions/69998/tabs-and-spaces-in-vim>

This allows a belt-and-braces approach: the repository will reject
attempts to commit with whitespace mistakes, but one's text editor can
be an ally in never getting to that point.

-- 
 \       “For fast acting relief, try slowing down.” —Jane Wagner, via |
  `\                                                       Lily Tomlin |
_o__)                                                                  |
Ben Finney