BUG: map nested dict on categorical Series prints a TypeError and ignores it

[adrien-berchet]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• (optional) I have confirmed this bug exists on the master branch of pandas.

---

Note: Please read this guide detailing how to provide the necessary information for us to reproduce your bug.

Code Sample, a copy-pastable example

tested = pd.Series(["key_1", "key_2"], dtype="category")
tested.map({"key_1": {"a": 1}, "key_2": {"a": 2}})

Problem description

The given code raises an exception but actually ignores it and returns the expected result. I think it would be better to ignore it silently. Note that it seems to happen only with categorical Series.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.map_locations()

TypeError: unhashable type: 'dict'
Exception ignored in: 'pandas._libs.index.IndexEngine._call_map_locations'
Traceback (most recent call last):
  File "pandas/_libs/hashtable_class_helper.pxi", line 4588, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'dict'
Out[10]: 
0    {'a': 1}
1    {'a': 2}
dtype: object

Expected Output

Out[10]: 
0    {'a': 1}
1    {'a': 2}
dtype: object

Output of pd.show_versions()

INSTALLED VERSIONS

commit : f2c8480
python : 3.8.5.final.0
python-bits : 64
OS : Linux
OS-release : 5.4.0-70-generic
Version : #78-Ubuntu SMP Fri Mar 19 13:29:52 UTC 2021
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : fr_FR.UTF-8
LOCALE : fr_FR.UTF-8

pandas : 1.2.3
numpy : 1.20.2
pytz : 2021.1
dateutil : 2.8.1
pip : 20.2.2
setuptools : 49.6.0
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : 7.22.0
pandas_datareader: None
bs4 : None
bottleneck : None
fsspec : 0.8.7
fastparquet : None
gcsfs : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : 1.3.23
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
numba : None

[attack68]

the same also occurs on master.

[phofl]

If I execute this in the debugger the code exits

Traceback (most recent call last):
  File "pandas/_libs/hashtable_class_helper.pxi", line 5185, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'dict'

Process finished with exit code 1