[issue43656] TracebackException or StackSummary.extract with capture_locals=True fail to catch exceptions raised by repr() on value of frame local variable in FrameSummary.__init__.

[Andrei Kulakov]

Andrei Kulakov <andrei.avk at gmail.com> added the comment:

Martin:

I have a couple of concerns:

 - Generally (AFAIK) Python is very conservative about silencing arbitrary exceptions. There are a few functions with args like `ignore_errors`, but those are for errors in the logic of respective functions. I don't recall examples where any error would be silenced via an argument, but if there are such cases, it would be interesting to look into how the design decision was made.

In this case of course arbitrary exceptions coming any objects' __repr__ may be silenced.

There is a clear and very explicit way to catch exceptions via try/except and as a dev, I would really want to be able to look at a module, look at all try/except clauses and be confident that exceptions are not silenced elsewhere.

 - You are targeting this fix to production use, but realistically, if merged, it will be used both in testing and production. Which means, by not seeing these exceptions in testing, you will have a higher chance of deploying them to production where they can surface in other circumstances.

IOW, as a dev I might prefer to see these errors early and often, rather than have a mechanism that ends up silencing errors more broadly than intended.

I'm not saying this fix should be rejected, but that there's a tricky balance here -- and I don't feel confident enough about this solution to approve the PR if I reviewed it.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43656>
_______________________________________