Re: "" gives an empty string, while "".idup gives null

[Mike Parker]

On 8/3/2011 11:23 PM, simendsjo wrote:
On 03.08.2011 15:49, bearophile wrote:
simendsjo:
void main() {
assert(is(typeof("") == typeof("".idup))); // both is immutable(char)[]

assert("" !is null);
assert("".idup !is null); // fails - s is null. Why?
}

I think someone has even suggested to statically forbid "is null" on
strings :-)

Bye,
bearophile

How should I test for null if not with "is null"? There is a difference
between null and empty, and avoiding this is not necessarily easy or
even wanted.
I couldn't find anything in the specification stating this difference.
So... Is it a bug?


This is apparently a bug. Somehow, the idup is clobbering the pointer. 
You can see it more clearly here:

void main()
{
        assert("".ptr);
        
        auto s = "".idup;
        assert(s.ptr); // boom!
}