I am familiar with things like
if ( isDefined( 'URL' ) ) structAppend( request.context, URL );
if ( isDefined( 'Form' ) ) structAppend( request.context, Form );
Which is how FW/1 builds rc. I recently got handed some code that does this
_inputs = duplicate(url);
structAppend(_inputs, form);
What is duplicate() doing here? How is that different from structAppend()?
I wonder if the original developer had come across issues when using the StructCopy() method and carried that over into their code for the StructAppend() method? I know that the StructCopy() method will copy nested structures by reference which can bite you. That is an example of when I use the Duplicate() method (to make a completely new copy of a structure).
I don't think that StructAppend() works that way though. Perhaps they wrote that code in an overabundance of caution. Obviously, this is just a guess.
The StructCopy() method is documented to copy by reference.
Copies a structure. Copies top-level keys, values, and arrays in the structure by value; copies nested structures by reference.