Re: pre-commit hook to reject whitespace

[John Szakmeister <john@szakmeister.net>]

On Fri, Jun 3, 2011 at 7:58 PM, Neal Kreitzinger <nkreitzinger@gmail.com> wrote:
> On 6/3/2011 6:31 PM, Neal Kreitzinger wrote:
>>
>> The reference manuals state in the hooks documentation that the pre-commit
>> hook sample will reject whitespace only changes.  However, the
>> pre-commit.sample in the 1.7.1 and 1.7.5.4 downloads do not appear to do
>> this (I'm new to linux scripts).  The appear to only reject non-ascii
>> filenames.  Does someone have a pre-commit hook example I can use to
>> reject
>> whitespace-only changes?  Thanks!
>>
> As someone kindly pointed out, the documentation actually says:
> "The default 'pre-commit' hook, when enabled, catches introduction of lines
> with trailing whitespaces and aborts the commit when such a line is found."
>
> I'm not seeing this functionality in the pre-commit.sample for 1.7.1 or
> 1.7.5.4.

I've never tried that hook script myself, but it appears to be on the last line:
   exec git diff-index --check --cached $against --

In particular, the --check option says:
    Warn if changes introduce trailing whitespace or an indent that
uses a space before a tab. Exits with non-zero status if problems are
found. Not compatible with --exit-code.

HTH!

-John