pylint: fix misplaced-bare-raise

[vamsi-verma-s]

• one of the issues in STYLE fix pylint issues #48855
• All code checks passed.

[akx]

This would raise the exception anew and so lose the original traceback. Is that on purpose?

[vamsi-verma-s]

missed that, it wasn't the intention. Do you think something like below would suffice?

Suggested change

	raise err
	raise ValueError(err) from err

[MarcoGorelli]

please wait to merge, I think this is might be a bug in pylint

[MarcoGorelli]

OK seems like pylint just doesn't detect this, as _catch_deprecated_value_error is always used within an except context

e.g. pylint would also raise on

def raise_exception(err: Exception):
    raise

try:
    1/0
except ZeroDivisionError as err:
    raise_exception(err)

I think we can just ignore this inline, referencing this PR:

raise  # pylint: disable=misplaced-bare-raise GH49018

[MarcoGorelli]

Hi @akx - are you sure about your raise err losing the traceback? I just tried it, and with raise err the traceback looks the same

With just raise:

Traceback (most recent call last):
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1116, in __setitem__
    self._set_with_engine(key, value)
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1186, in _set_with_engine
    loc = self.index.get_loc(key)
  File "/home/marcogorelli/pandas-dev/pandas/core/indexes/range.py", line 395, in get_loc
    self._check_indexing_error(key)
  File "/home/marcogorelli/pandas-dev/pandas/core/indexes/base.py", line 6028, in _check_indexing_error
    raise InvalidIndexError(key)
pandas.errors.InvalidIndexError: [False  True False]

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "t.py", line 51, in <module>
    ser[mask] = 1
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1173, in __setitem__
    self._where(~key, value, inplace=True)
  File "/home/marcogorelli/pandas-dev/pandas/core/generic.py", line 9781, in _where
    new_data = self._mgr.putmask(mask=cond, new=other, align=align)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/managers.py", line 410, in putmask
    return self.apply(
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/managers.py", line 350, in apply
    applied = getattr(b, f)(**kwargs)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/blocks.py", line 1534, in putmask
    _catch_deprecated_value_error(err)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/blocks.py", line 1532, in putmask
    values._putmask(mask, new)
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/string_.py", line 421, in _putmask
    ExtensionArray._putmask(self, mask, value)
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/base.py", line 1517, in _putmask
    self[mask] = val
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/string_.py", line 404, in __setitem__
    raise ValueError(
ValueError: Cannot set non-string value '1' into a StringArray.

with raise err:

Traceback (most recent call last):
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1116, in __setitem__
    self._set_with_engine(key, value)
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1186, in _set_with_engine
    loc = self.index.get_loc(key)
  File "/home/marcogorelli/pandas-dev/pandas/core/indexes/range.py", line 395, in get_loc
    self._check_indexing_error(key)
  File "/home/marcogorelli/pandas-dev/pandas/core/indexes/base.py", line 6028, in _check_indexing_error
    raise InvalidIndexError(key)
pandas.errors.InvalidIndexError: [False  True False]

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "t.py", line 51, in <module>
    ser[mask] = 1
  File "/home/marcogorelli/pandas-dev/pandas/core/series.py", line 1173, in __setitem__
    self._where(~key, value, inplace=True)
  File "/home/marcogorelli/pandas-dev/pandas/core/generic.py", line 9781, in _where
    new_data = self._mgr.putmask(mask=cond, new=other, align=align)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/managers.py", line 410, in putmask
    return self.apply(
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/managers.py", line 350, in apply
    applied = getattr(b, f)(**kwargs)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/blocks.py", line 1534, in putmask
    _catch_deprecated_value_error(err)
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/blocks.py", line 1986, in _catch_deprecated_value_error
    raise err # pylint: disable=misplaced-bare-raise GH49018
  File "/home/marcogorelli/pandas-dev/pandas/core/internals/blocks.py", line 1532, in putmask
    values._putmask(mask, new)
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/string_.py", line 421, in _putmask
    ExtensionArray._putmask(self, mask, value)
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/base.py", line 1517, in _putmask
    self[mask] = val
  File "/home/marcogorelli/pandas-dev/pandas/core/arrays/string_.py", line 404, in __setitem__
    raise ValueError(
ValueError: Cannot set non-string value '1' into a StringArray.

So, I think it's fine to just do raise err and not have to ignore any checks? (apologies @vamsi-verma-s for conflicting requests)

---

Code to trigger this:

ser = pd.Series(["a", "b", "c"], dtype='string')
mask = np.array([False, True, False])
ser[mask] = 1

[vamsi-verma-s]

Hi @MarcoGorelli

I have reverted to original change. I was a bit confused here over loosing traceback.
If my understanding is correct, since we are raising with the same exception instance, the traceback would still be attached to it and don't need to do something like raise ValueError('same error').with_traceback(err.__traceback__)

[MarcoGorelli]

Thanks @vamsi-verma-s

[vamsi-verma-s]

Thank you all for reviewing this.