Ovirt devel - Jul 2008 - a pox on whitespace

Here are some things we can do to avoid
bad whitespace (not just trailing whitespace)
without causing too much development pain:

server-side enforcement
  have a git pre-push hook check for and reject changes that
  add trailing blanks.  This typically cannot be circumvented.
  However, I've set up similar things whereby exceptional cases
  can be white-listed.

local-commit-enforcement
  With recent git, just do this in each of your
  working directories:  chmod a+x .git/hooks/pre-commit
  and a commit that would have added bad whitespace will fail.
  (you can circumvent it with git commit's --no-verify (-n) option)

"make check"-style detection
  Add a top-level Makefile rule that fails if any file
  contains bad whitespace.  Then establish policy that one must
  pass "make check"s tests before committing/pushing.

editor highlighting
  Enable syntax highlighting in your editor and tell it to
  display bad whitespace.  For example, add this to your ~/.vimrc:

    let c_space_errors=1
    highlight RedundantSpaces ctermbg=red guibg=red
    match RedundantSpaces /\s\+$\| \+\ze\t/

For emacs, you might want to try show-wspace.el (I haven't,
but it's the first google hit for "highlight whitespace emacs")
<http://www.emacswiki.org/cgi-bin/wiki/show-wspace.el>, or maybe
you already use font-lock mode, which you can customize.

Jim

On Wed, Jul 16, 2008 at 07:21:46PM +0200, Jim Meyering
wrote:
> Here are some things we can do to avoid
> bad whitespace (not just trailing whitespace)
> without causing too much development pain:
> 
> server-side enforcement
>   have a git pre-push hook check for and reject changes that
>   add trailing blanks.  This typically cannot be circumvented.
>   However, I've set up similar things whereby exceptional cases
>   can be white-listed.
I'd be in favor of putting this into place immediately.
 
> local-commit-enforcement
>   With recent git, just do this in each of your
>   working directories:  chmod a+x .git/hooks/pre-commit
>   and a commit that would have added bad whitespace will fail.
>   (you can circumvent it with git commit's --no-verify (-n) option)
And this... how recent a git version?
> "make check"-style detection
>   Add a top-level Makefile rule that fails if any file
>   contains bad whitespace.  Then establish policy that one must
>   pass "make check"s tests before committing/pushing.
This is probably less compelling for us since we don't really compile
the app (although I habitually still run make and then install the RPM
to test changes).
> editor highlighting
>   Enable syntax highlighting in your editor and tell it to
>   display bad whitespace.  For example, add this to your ~/.vimrc:
> 
>     let c_space_errors=1
>     highlight RedundantSpaces ctermbg=red guibg=red
>     match RedundantSpaces /\s\+$\| \+\ze\t/
> 
> For emacs, you might want to try show-wspace.el (I haven't,
> but it's the first google hit for "highlight whitespace
emacs")
> <http://www.emacswiki.org/cgi-bin/wiki/show-wspace.el>, or maybe
> you already use font-lock mode, which you can customize.
This is voluntary I guess but seems like a good thing for developers
to do.

Also needed might be a quick script to remove trailing whitespace from
a file?

Thanks for this,
--Hugh