ValueError: valid range for prec is [1, MAX_PREC] #338
Description
Describe the bug
ValueError is raised when using "0.x" Decimal as value and significant_digits is lower than the number of decimal digits used as input.
To Reproduce
Python 3.8.13 (default, Jun 8 2022, 12:42:16)
[GCC 11.2.0] on linux
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>>> from deepdiff import DeepDiff
>>> from decimal import Decimal
>>> dict1 = {'key': Decimal('0.000')}
>>> dict2 = {'key': Decimal('0.0001')}
>>>
>>> DeepDiff(dict1, dict2) # OK
{'values_changed': {"root['key']": {'new_value': Decimal('0.0001'), 'old_value': Decimal('0.000')}}}
>>>
>>> DeepDiff(dict1, dict2, significant_digits=2) # Should return {}
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 296, in __init__
self._diff(root, parents_ids=frozenset({id(t1)}), _original_type=_original_type)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1339, in _diff
self._diff_dict(level, parents_ids)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 547, in _diff_dict
self._diff(next_level, parents_ids_added)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1336, in _diff
self._diff_numbers(level)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1145, in _diff_numbers
t1_s = self.number_to_string(level.t1,
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/helper.py", line 327, in number_to_string
ctx.prec = len(tup.digits) + tup.exponent + significant_digits
ValueError: valid range for prec is [1, MAX_PREC]
>>>
>>> DeepDiff(dict1, dict2, significant_digits=3) # Should return {}
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 296, in __init__
self._diff(root, parents_ids=frozenset({id(t1)}), _original_type=_original_type)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1339, in _diff
self._diff_dict(level, parents_ids)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 547, in _diff_dict
self._diff(next_level, parents_ids_added)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1336, in _diff
self._diff_numbers(level)
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/diff.py", line 1148, in _diff_numbers
t2_s = self.number_to_string(level.t2,
File "/home/user/Development/project/venv/lib/python3.8/site-packages/deepdiff/helper.py", line 327, in number_to_string
ctx.prec = len(tup.digits) + tup.exponent + significant_digits
ValueError: valid range for prec is [1, MAX_PREC]
>>>
>>>
>>> DeepDiff(dict1, dict2, significant_digits=4) # OK
{'values_changed': {"root['key']": {'new_value': Decimal('0.0001'), 'old_value': Decimal('0.000')}}}Expected behavior
DeepDiff(dict1, dict2, significant_digits=2)-> Should return {}, not raise ValueError.DeepDiff(dict1, dict2, significant_digits=3)-> Should return {}, not raise ValueError.
OS, DeepDiff version and Python version (please complete the following information):
- OS: Ubuntu
- Version: 22.04 LTS
- Python Version: 3.8.13
- DeepDiff Version: 5.8.1
Additional context
>>> from decimal import Decimal
>>> Decimal('0.000').as_tuple()
DecimalTuple(sign=0, digits=(0,), exponent=-3)In helper.py, method number_to_string:
[...]
if isinstance(number, Decimal):
tup = number.as_tuple()
with localcontext() as ctx:
ctx.prec = len(tup.digits) + tup.exponent + significant_digits
number = number.quantize(Decimal('0.' + '0' * significant_digits))
[...]ctx.prec should be equal to the number of integer digits + significant_digits.
len(tup.digits) + tup.exponent is not a good way to get the number of integer digits (it fails for 0.x Decimal)