serializing "package_version" object causes infinite recursion

[jefshe]

The following R code causes RProtoBuf to infinitely recurse:

x <- package_version("1.2")
RProtoBuf::serialize_pb(x)

I did some digging and it looks like when this is because when sub indexing the list, the list returns itself:

x <- package_version("1.2")
identical(x,x[[1]])
> TRUE

this causes lapply(obj, rexp_obj) to never terminate.

Perhaps in these situations, we should call unlist?

[eddelbuettel]

The package_version object is a funny one. For kicks, can you check what happens with these two:

x1 <- as.raw(x)
x2 <- format(x)

I presume these travel fine. I am not quite where we'd have to go to stop the recursion. But your suggested check is a good one. If you have time to dig ...

[jefshe]

Just raised a PR.
The output I get:

> x1 <- as.raw(x)
Error: (list) object cannot be coerced to type 'raw'
> x2 <- format(x)
> x2
[1] "1.2"

[eddelbuettel]

No, I meant: what happens when you try to protobuf x1 or x2. I guess x1 is out anyway...

[jefshe]

> serialize_pb(format(x),NULL)
 [1] 08 00 2a 07 0a 03 31 2e 32 10 00
> unserialize_pb(serialize_pb(format(x),NULL))
[1] "1.2"

Ah, yep works as intended