On 17. 04. 22 19:20, Pablo Galindo Salgado wrote:
Hi,
We are currently debating in gh-88116 (https://github.com/python/cpython/issues/88116 <https://github.com/python/cpython/issues/88116>) what's the best way forward to update the APIs in the inspect module to include the new position information.
These APIs are inspect.getframeinfo, inspect.getouterframes, inspect.getinnerframes, inspect.stack and inspect.trace.
The problem is that these APIs return a named tuple that now needs to include several new attributes (or one 4 tuple for the positions). Being named tuples, if we add a new attribute, existing unpackings of the tuple will now fail because there are more elements or the elements are in different positions. Also, it will be quite weird to add the new attributes at the end but leave the line number at the beginning.
What's the best way to proceed here? The suggested way is to create a namedtuple subclass that adds the extra attributes but doesn't allow indexed access to it (there is a precedent to this in how we handled updating os.stat_result). I personally find this quite confusing but it certainly works. There may be other options.
IMO, that is the way to do it -- PyStructSequence. I'd then discourage indexed access. It is indeed confusing, but that's OK for something that's only there for backwards compatibility: - users who are confused should read the docs and update their code. - core devs can hopefully read a comment nearby and not be confused. (And I don't think it's worth deprecating and removing indexed access -- there's no reason to break code that works just because there's now a better API.)