When setting up webapi decorator state, we use Python's

functools.update_wrapper() to copy over standard function state. This

is good except if we're working with the same function as both the

source and target, then we can get into a state where we reach an

infinite loop.
This seems to be due to setting __wrapped__ on the function to point

to itself. This hasn't resulted in any issues in normal usage, but it

has impacted Sphinx during doc generation, as it just hits an infinite

loop walking the tree.
We now bail out immediately if we determine we're using the same

function for both arguments.

Unit tests pass.
Verified this got past a stuck state in Sphinx doc building.