neels has posted comments on this change by neels. ( https://gerrit.osmocom.org/c/python/pyosmocom/+/39600?usp=email )

Change subject: utils: add unrpad() ......................................................................

Patch Set 1:

(1 comment)

Patchset:

PS1: It turns out there *is* a surprising difference!

The rstrip() version causes this error in pySim.esim.saip, can you guess why:

File "/home/moi/s/esim/sysmo_esim_mgr/venv/lib/python3.13/site-packages/pySim/esim/saip/personalization.py", line 560, in decimal_hex_to_str return val.to_bytes().decode('ascii') ^^^^^^^^^^^^ AttributeError: 'str' object has no attribute 'to_bytes'

I stared for a while until I realized this code is using hexstr.to_bytes(). (hexstr is also here from pyosmocom.) hexstr has a magic trick:

def __getitem__(self, val) -> 'hexstr': # make sure slicing a hexstr will return a hexstr return hexstr(super().__getitem__(val))

so with the unrpad() implementation from this patch, a hexstr stays a hexstr. When using val.rstrip('f'), the hexstr becomes a str, and then there is no to_bytes() function.

For now I solved it in the calling code as a local function

def unrpad(s: hexstr, c='f') -> hexstr: return hexstr(s.rstrip(c))

but something like this next to rpad() now seems useful again... what do you think?