Morten Welinder [off-list ref] writes:

Someone needs to audit the usage of isspace, tolower, and
friends.  There are things like this in the code:

static int is_dev_null(const char *str)
{
	return !memcmp("/dev/null", str, 9) && isspace(str[9]);
}

Since str[9] is of type char it should not be used as a argument to
isspace directly,
but rather be cast to unsigned char:

    ... isspace((unsigned char)str[9]);

Huh?  isspace is "int isspace(int)".  Presumably standard
integral promotion rules applies here whether char is signed or
unsigned, doesn't it?

The snippet you quoted is from apply.c, and I would say what is
more problematic is that we do not force C locale while parsing
the diff (see another thread -- we would want to process diffs
as byte streams).