Unpack decoding error

[RomoloPoliti-INAF]

I'm decoding a hex string:
data= '00000000633c2042000d5bdf633c20450007a86a00000001034c00cc000000a8183803e8000003c3000028c100000000034c00000000000000000000'
format_bit='bytes:2,uint:8,uint:6,uint:2,'+5*'uint:32,'+2 'uint:16,'+'uint:32,'+2'uint:4,'+4*'uint:1,'+2*'uint:2,'+'uint:16,'+2*'uint:32,'+8*'uint:16,'
dp = BitStream(hex=data[0:120]).unpack(fmt=format_bit)

If I use bitstring version 4.1.4, the string will be decoded correctly.

If I use version 4.2.0 I obtain the error:

---

ValueError Traceback (most recent call last)
File ~/Documents/Progetti/JANUS/Software/hk_getter/venv/lib/python3.12/site-packages/bitstring/bits.py:1186, in Bits._readlist(self, fmt, pos, **kwargs)
1185 try:
-> 1186 name, length = utils.parse_name_length_token(t, **kwargs)
1187 except ValueError:

File ~/Documents/Progetti/JANUS/Software/hk_getter/venv/lib/python3.12/site-packages/bitstring/utils.py:94, in parse_name_length_token(fmt, **kwargs)
93 else:
---> 94 raise ValueError(f"Can't parse 'name[:]length' token '{fmt}'.")
95 return name, length

ValueError: Can't parse 'name[:]length' token ''.

During handling of the above exception, another exception occurred:

ValueError Traceback (most recent call last)
Cell In[63], line 1
----> 1 dp = BitStream(hex=data[0:120]).unpack(fmt=format_bit)

File ~/Documents/Progetti/JANUS/Software/hk_getter/venv/lib/python3.12/site-packages/bitstring/bits.py:1169, in Bits.unpack(self, fmt, **kwargs)
1154 def unpack(self, fmt: Union[str, List[Union[str, int]]], **kwargs) -> List[Union[int, float, str, Bits, bool, bytes, None]]:
1155 """Interpret the whole bitstring using fmt and return list.
1156
1157 fmt -- A single string or a list of strings with comma separated tokens
(...)
1167
1168 """
-> 1169 return self._readlist(fmt, 0, **kwargs)[0]

File ~/Documents/Progetti/JANUS/Software/hk_getter/venv/lib/python3.12/site-packages/bitstring/bits.py:1188, in Bits._readlist(self, fmt, pos, **kwargs)
1186 name, length = utils.parse_name_length_token(t, **kwargs)
1187 except ValueError:
-> 1188 dtype_list.append(Dtype('bits', int(t)))
1189 else:
1190 dtype_list.append(Dtype(name, length))

ValueError: invalid literal for int() with base 10: ''

---

Thank you for your work and support

Romolo

[scott-griffiths]

Thank you for the bug report.

I believe the issue is that the format string ends in a comma, so the new logic is expecting another value that isn't there. It should be fairly simple to fix though, so I'll add it to my list for the 4.2.1 release.

Cheers.

[scott-griffiths]

This should be working again the 4.2.1 release.