UDFs must not modify arguments passed by reference

[nobu-k]

UDFs can receive references such as arrays or maps. However, they must not change those arguments. Add notes about this in the Server Programming part.

[tgpfeiffer]

Is it safe, by the way, to return one of the input parameters as is? I imagine that if we have something like

SELECT RSTREAM oneItem, identity(oneItem) AS anotherItem FROM ...

and the identity function just returns the input parameter, is it possible that we run into trouble later when oneItem and anotherItem point to the same object?

[nobu-k]

I think it should be safe.

[tgpfeiffer]

Code-wise, this has been addressed by the introduction of the TFSharedData flag.