Unhelpful error message

[Thomas Nyberg]

On 06/06/2017 11:38 AM, Jon Ribbens wrote:
> On 2017-06-06, Peter Otten <__peter__ at web.de> wrote:
>> ...but not the empty string:
>>
>>>>> float("")
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in <module>
>> ValueError: could not convert string to float: 
>>
>> Maybe there were some backward compatibility concerns that I lack the 
>> fantasy to imagine.
> 
> It's a little odd, PyFloat_FromString just calls:
> 
>     PyErr_Format(PyExc_ValueError,
>                  "could not convert string to float: %R", v);
> 
> which should be appending the repr() of the argument to the error
> message, and there's no code I can see anywhere that would be
> special-casing the empty string and avoiding inserting "''".
> 
If the string is empty, then the line:

    if (end != last) {

does not evaluate to true, so you end up skipping the error you're
referring to and instead executing these lines:

    else if (x == -1.0 && PyErr_Occurred()) {
        return NULL;
    }

So maybe the logic should be fixed here since the empty string is
basically taking a separate logical path than it philosophically should
(imo).

Cheers,
Thomas