Re: Bug in default commit hook (improperly forbidding a single blank line at EOF)

From: Jeff King <peff@peff.net>
Date: Sep 8, 2015, 04:55 UTC
Message-ID: <20150908045504.GA26331@sigill.intra.peff.net>
In-Reply-To: <55EE3BD9.7020707@gmail.com>

On Mon, Sep 07, 2015 at 06:37:29PM -0700, Raymond Jennings wrote:

Show 5 quoted lines

> Please see https://bugs.gentoo.org/show_bug.cgi?id=559920 for further
> details.
> 
> Files *should* have a single blank line at the end, because a line should
> always have a newline at the end.

I'm not sure I follow. Lines should have a newline at the end, but there is no need to start a _new_ blank line. So a file with zero bytes has no lines (and no newline).

A file that contains a single line, like "one\n", has each line end in a newline, and the file ends in a newline. There is no blank line.

A file like "one\n\n" has two lines: one with text, and a blank line at the end.

Can you clarify (preferably by showing a byte sequence of the file in question) what file you are feeding to the hook, what output you get, and what output you expect?

> Adding a newline to the end of a file whose last line doesn't have one
> should be legal...as long as you don't create empty lines at the end.

If you mean turning "foo" (a file with no newline!) into "foo\n", I agree that is legal, and does not create an empty blank line at the end. But I don't think the hook complains about that.

E.g., we can create a sequence of file content:

  git init

  echo -n one >file
  git add file
  git commit -m 'no newline'

  echo >>file
  git add file
  git commit -m 'complete line'

  echo >>file
  git add file
  git commit -m 'add a blank line'

and run "log --check", which runs the same code that the pre-commit hook does:

  git log --check

Git complains only about the final, which looks right to me. If you want to redefine git's idea of which whitespace is worth complaining about, try:

  git config core.whitespace -blank-at-eof

See the description of core.whitespace in "git help config" for the complete list. You can also set it per-file using gitattributes. See "git help attributes", section "Checking whitespace errors".

-Peff