Suggestion to use bare raise instead of raise exc

[zanieb]

I've been championing the use of raise instead of raise exc when re-raising a captured exception as it removes a frame from the traceback. When many exceptions are chained, this can make a significant difference in the length of a traceback.

WRONG: Extra frame included in traceback

try:
    raise ValueError("1")
except Exception as exc:
    raise exc

Traceback (most recent call last):
  File "/Users/mz/dev/prefect/example.py", line 4, in <module>
    raise exc
  File "/Users/mz/dev/prefect/example.py", line 2, in <module>
    raise ValueError("1")
ValueError: 1

RIGHT: No frame added when the exception is re-raised

try:
    raise ValueError("1")
except Exception:
    raise

Traceback (most recent call last):
  File "/Users/mz/dev/prefect/example.py", line 2, in <module>
    raise ValueError("1")
ValueError: 1

I don't think this is covered by any existing linters. I checked flake8 and pylint.

[tjkuson]

As I understand it, this is covered by tryceratops and is implemented in ruff as TRY201.

[charliermarsh]

Thanks for the clear issue :) My read is that this is covered by TRY201 as @tjkuson mentioned -- but just LMK if I'm misunderstanding.

[zanieb]

Cool! I'm interested in adding explanation there as they call it "redundant" but it has an actual runtime effect.

What kind of criteria is there for a rule being included by default?

I've noticed this is also not an auto-fixable issue but it seems like it could be

example.py:4:11: TRY201 Use `raise` without specifying exception name
Found 1 error.

[tylerlaprade]

Hi @zanieb and @charliermarsh, I would also enjoy seeing this rule become auto-fixable.