On empty string, internal error: ValueId cannot be zero

[niemeyer]

Hello again,

I'm getting an error while attempting to add an edge from Go which is set to an empty string:

rpc error: code = Unknown desc = failed to apply mutations error: internal error: ValueId cannot be zero

The code looks like the typical edge insertion, I believe:

edge = node.Edge("svalue")
err = edge.SetValueString(v)
if err == nil {
        req.Set(edge)
}
if err != nil {
        return err
}

Hacking the value to be non-empty in those specific cases with v = "-" makes the code work fine.

Setting empty strings via the browser also works fine.

[pawanrawal]

Thanks for reporting the issue @niemeyer. I have pushed a fix as part of cb8a79f and it would be part of the next release.

[niemeyer]

Thanks for the quick fix @pawanrawal.

Reading the fix, do we have some special semantics by setting a string value with _nil_? What happens if that string happens to be found in the data itself?

[niemeyer]

Yes, that's indeed true as confirmed with code. I'm opening a separate issue about it.