Re: [PATCH v2 2/4] config: drop file pointer validity check in get_next_char()

On Tue, Mar 12, 2013 at 05:00:56PM +0100, Heiko Voigt wrote:

On Tue, Mar 12, 2013 at 07:00:03AM -0400, Jeff King wrote:

quoted

On Sun, Mar 10, 2013 at 05:58:57PM +0100, Heiko Voigt wrote:

quoted

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.

Ok if you say so I will do that :-). I was thinking about adding a patch
that would remove cf as a global variable and explicitely pass it down
to get_next_char. That makes it more obvious that it actually is != NULL.
Looking at your callgraph I do not think its that much work. What do you
think?

I just had a look and unfortunately there are other functions that use
this variable (namely handle_path_include) for which its not that easy
to pass this in. So I will just drop the check here.

Cheers Heiko