Re: [PATCH 00/14] numparse module: systematically tighten up integer parsing

On 03/17/2015 07:48 PM, Junio C Hamano wrote:

Michael Haggerty [off-list ref] writes:

quoted

When I looked around, I found scores of sites that call atoi(),
strtoul(), and strtol() carelessly. And it's understandable. Calling
any of these functions safely is so much work as to be completely
impractical in day-to-day code.

git-compat-util.h has two functions, strtoul_ui() and strtol_i(), that
try to make parsing integers a little bit easier.

Exactly.  They were introduced to prevent sloppy callers from
passing NULL to the &end parameter to underlying strtoul(3).  The
first thing that came to my mind while reading your message up to
this point was "why not use them more, tighten them, adding
different variants if necessary, instead of introducing an entirely
new set of functions in a new namespace?"

Here were my thoughts:

* I wanted to change the interface to look less like
  strtol()/strtoul(), so it seemed appropriate to make the names
  more dissimilar.

* The functions seemed long enough that they shouldn't be inline,
  and I wanted to put them in their own module rather than put
  them in git-compat-util.h.

* It wasn't obvious to me how to generalize the names, strtoul_ui()
  and strtol_i(), to the eight functions that I wanted.

That being said, I'm not married to the names. Suggestions are
welcome--but we would need names for 8 functions, not 4 [1].

Michael

For example:

quoted

* Am I making callers too strict? In many cases where a positive
  integer is expected (e.g., "--abbrev=<num>"), I have been replacing
  code like

      result = strtoul(s, NULL, 10);

  with

      if (convert_i(s, 10, &result))
              die("...");

I think strictness would be good and those who did "--abbrev='  20'"
deserve what they get from the additional strictness, but 

	if (strtol_i(s, 10, &result))

would have been more familiar.

[1] It could be that when we're done, it will turn out that some of the
eight variants are not needed. If so, we can delete them then.

-- 
Michael Haggerty
mhagger@alum.mit.edu