Unnecessary bare except at class Block, function interpolate hides actual error

[seboktamas]

Code Sample, a copy-pastable example if possible

# Minimal example:
import pandas as pd
df = pd.Series([0,1,pd.np.nan,3,4])
df.interpolate(method='spline')
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "D:\venvs\food_and_drinking\lib\site-packages\pandas\core\generic.py", line 6034, in interpolate
    **kwargs)
  File "D:\venvs\food_and_drinking\lib\site-packages\pandas\core\internals.py", line 3702, in interpolate
    return self.apply('interpolate', **kwargs)
  File "D:\venvs\food_and_drinking\lib\site-packages\pandas\core\internals.py", line 3581, in apply
    applied = getattr(b, f)(**kwargs)
  File "D:\venvs\food_and_drinking\lib\site-packages\pandas\core\internals.py", line 1168, in interpolate
    raise ValueError("invalid method '{0}' to interpolate.".format(method))
ValueError: invalid method 'spline' to interpolate.

Expected output

ValueError: You must specify the order of the spline or polynomial.

Problem description

If interpolation parameter not specified, it raises an error, which states invalid method
internals.py:1152:1155
try:
m = missing.clean_interp_method(method, **kwargs)
except:
m = None

If there is no such try/except block around the missing.clean_interp_method function call, we would get the proper exception from mising.py/clean_interp_method.

Pandas version: 0.23.4

[TomAugspurger]

Do you have a minimal example? http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports

[seboktamas]

Minimal example:
import pandas as pd
df = pd.Series([0,1,pd.np.nan,3,4])
df.interpolate(method='spline')

[TomAugspurger]

For clarity, the expected output is

ValueError: You must specify the order of the spline or polynomial.

@seboktamas can you edit your original post to include the minimal example and the expected output?