Re: [PATCH] use xstrdup, not strdup in ll-merge.c

From: Jim Meyering <jim@meyering.net>
Date: Jun 15, 2009, 08:02 UTC
Message-ID: <87fxe2lybr.fsf@meyering.net>
In-Reply-To: <81b0412b0906141503v14484d9fyea56198910305bfc@mail.gmail.com>

Alex Riesen wrote:

Show 9 quoted lines

> 2009/6/14 Jim Meyering <jim@meyering.net>:
>> @@ -231,7 +231,7 @@ static int read_merge_config(const char *var, const char *value, void *cb)
>>
>>        if (!strcmp(var, "merge.default")) {
>>                if (value)
>> -                       default_ll_merge = strdup(value);
>> +                       default_ll_merge = xstrdup(value);
>
> read_merge_config has a failure mode (where it returns -1), why not use it?

I didn't even consider it, because it would be inconsistent with the other heap-allocation functions used there (xcalloc, xmemdupz).

However, now that I do, it looks like that would mean adding four times the same code (including conditionals and code to generate a diagnostic via a call to error -- or a goto). Why bother, when all of that is already encapsulated in xmalloc? Maybe because you want to be able to continue after an allocation failure? If a small strdup allocation fails, odds are good that the code won't be able to do anything useful, so when not in library code, cleanest is simply to exit.

In addition, if you insist on using strdup, you'll probably want to be consistent and use calloc and memdupz, too. Adding all of the code required to recover from those failures and to avoid leaks would be messy.