I double checked the current behaviour, and rediscovered something I had forgotten: when inspect.getargspec and inspect.getfullargspec were converted to be based on the inspect.signature machinery, we had to decide whether or not to follow wrapper chains to report the underlying signature or not.

We opted to continue reporting the "surface signature" for compatibility with the behaviour of these APIs in previous versions of Python (including introspection tools that handle wrapper chains themselves), while encouraging introspection tools to migrate to using the more capable inspect.signature API instead: https://docs.python.org/3/library/inspect.html#inspect.getfullargspec

If a particular introspection tool reports incorrect signatures in 3.4+, then that's an issue with that particular tool needing to be made wrapper chain aware.

I'll also ping Aaron Iles about potentially bringing https://funcsigs.readthedocs.org/ up to date with the features in the Python 3.4 version of the library, including the helper to traverse wrapper chains correctly: https://docs.python.org/3/library/inspect.html#inspect.unwrap