From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff King <peff@peff.net>
Subject: Re: [PATCH v2 2/4] config: drop file pointer validity check in
 get_next_char()
Date: Tue, 12 Mar 2013 07:00:03 -0400
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 <20130310165857.GC1136@sandbox-ub.fritz.box>
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Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org,
	Jens Lehmann <jens.lehmann@web.de>,
	Ramsay Jones <ramsay@ramsay1.demon.co.uk>
To: Heiko Voigt <hvoigt@hvoigt.net>
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On Sun, Mar 10, 2013 at 05:58:57PM +0100, Heiko Voigt wrote:

> The only location where cf is set in this file is in do_config_from().
> This function has only one callsite which is config_from_file(). In
> config_from_file() its ensured that the f member is set to non-zero.
> [...]
> -	if (cf && ((f = cf->f) != NULL)) {
> +	if (cf) {

I still think we can drop this conditional entirely. The complete call
graph looks like:

  git_config_from_file
    -> git_parse_file
      -> get_next_char
      -> get_value
          -> get_next_char
          -> parse_value
              -> get_next_char
      -> get_base_var
          -> get_next_char
          -> get_extended_base_var
              -> get_next_char

That is, every path to get_next_char happens while we are in
git_config_from_file, and that function guarantees that cf = &top, and
that top.f != NULL.  We do not have to even do any analysis of the
conditions for each call, because we never change "cf" nor "top.f"
except when we set them in git_config_from_file.

-Peff