Extend possibly-used-before-assignment to definitions in try then used in finally or after

[lbenezriravin]

Potentially related to #2615. Not sure if these would both be fixed by the same patch, so I'm making a new issue.

Is your feature request related to a problem? Please describe

The following code passes pylint:

try:
   foo = 1 / 0
except:
   pass
print(foo)

But raises an UnboundLocalError when run.

Describe the solution you'd like

Pylint already has an undefined-loop-variable warning for a similar case that could result in the same error:

for foo in []:
    pass
print(foo)

I feel that the former code should raise a warning if that latter code does. More generally, I don't expect UnboundLocalError from any code that passes pylint, but I'm not sure if that guarantee is possible.

Additional context

Thanks for your work on this tool!

[PCManticore]

Thanks @lbenezriravin This makes sense.

[Pierre-Sassoulas]

Closing as duplicate of #5524

[DanielNoord]

This was actually not a duplicate see: https://github.com/PyCQA/pylint/pull/5764#issuecomment-1032803372.

A very relevant comment was made by @cdce8p in #5524 here:

Another idea. I like how pyright names it. Maybe possibly-unbound?

"a" is possibly unbound

Maybe consider-using-try-else

We shouldn't really "force" users to add an else case. There are just to many alternatives. You could for example assign a default value before you enter the try block.

[jacobtylerwalls]

Implementation tip: when checking whether the except handlers define a name, raise, or return, consider using NamesConsumer._defines_name_raises_or_returns() from #5764

[Pierre-Sassoulas]

pyright has possibly unbound, mypy has possibly-undefined, I think we should introduce either one of those two names in pylint on top of undefined-variable (maybe possibly-undefined-variable for consistency)