RE: [GSoC][RFC] Replace use of atoi() with strtol_i(), as a microproject

[<rsbecker@nexbridge.com>]

On Wednesday, January 10, 2024 12:38 PM, Mohit Marathe wrote:
>>In https://public-inbox.org/git/xmqqjzpjsbjl.fsf@gitster.g/ Junio says:
>>
>>"Some places use atoi() immediately followed by strspn() to skip over
>>digits, which means they are parsing an integer and want to continue
>>reading after the integer, which is incompatible with what
>>strtol_i() wants to do.  They need either a separate helper or an
>>updated strtol_i() that optionally allows you to parse the prefix and
>>report where the integer ended, e.g., something like:"
>>
>>and then he suggests the above helper.
>>
>>So it seems that the two instances you found look like good places
>>where Junio says the new helper could be useful.
>>
>>Now if you want to continue further on this, I think you would need to
>>take a closer look at those two instances to see if replacing atoi()
>>there with the new helper would improve something there or not. If you
>>find it would improve something, be sure to explain what would be
>>improved in the commit message.
>
>I took a closer look at `builtin/patch-id.c` and it seems replacing `atoi()` (which is
>used to parse numbers in the hunk header) wouldn't improve anything, unless I'm
>missing something.
>
>So then I tried finding other places where `atoi()` can be replaced but I find it
>difficult to find any reason that would justify the change.
>So far I've only looked at few of the MANY occurrences of `atoi()`.
>As far as I understand, the only advantage of `strtol_i()` over `atoi()` is better error
>handling. And most of places I've seen either already takes care of that or does not
>need that at all.

I am not sure this is a good idea. The error detection inside strtol_i() reports a -1 if the supplied text value is invalid. This does not differentiate between an invalid value and a valid "-1" supplied. Replacing all instances of atoi() with strtol_i() will likely cause breakages as the error semantics are different between the two.
--Randall