I wonder if we should add the same thing to PEP 8?

I wonder if we should add the same thing to PEP 8?

Yes. I'll create a separate PR for PEP 8.

As I said over here, I've changed my mind on whether this is a useful recommendation to add to PEP 7 (and 8).

The PEP 8 change seems potentially far more impactful than the PEP 7 one, as the latter will mainly only impact the stdlib, while the former is treated as the de-facto standard for formatting all Python code, which theoretically could affect on the order of >=billions of lines of code versus less than 500 000. So I could see a justification to apply this only to PEP 7 on those grounds, However, on the other hand, it might be inconsistent to only do one and not the other, unless there is another plausible reason it should apply to the C code but not the Python code.

I agree, CAM, that it could make sense to keep the PEP 7 change. Speaking from my own experience, I rarely need to grep for exception messages in Python files; I can find those location directly from a traceback. If I grep for an exception message, it is almost always because I want to find the C code that raised it.