Incorrect Results for Parssing Data Time

[OrianeK]

Hi,
I am a high school student just starting to learn about testing techniques. I found a bug in the latest version (0.6.1) of maya while doing some fuzzing using the fuzzing tool Atheris. The reproducing process is shown below:

maya.parse('may15,2021').datetime()

result
datetime.datetime(2022, 5, 15, 0, 0, tzinfo=<UTC>)

my Environment

Python 3.8.10 (default, Mar 15 2022, 12:22:08) 
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import maya
>>> print(maya.__version__)
0.6.1
>>> 

I am not very sure about the bug so I would very much appreciate any kind of feedback regarding it.
Thanks.

Looks like the issue is from underlying pendulum parser.

Python 3.11.5 (main, Aug 24 2023, 12:23:19) [Clang 15.0.0 (clang-1500.0.40.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from maya import parse
>>> dt = "june 15,1987"
>>> parse(dt)
<MayaDT epoch=1686787200.0>
>>> parse(dt).datetime()
datetime.datetime(2023, 6, 15, 0, 0, tzinfo=<UTC>)
>>> from pendulum import parse
>>> parse(dt)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/santhoshsolomon/Desktop/venv/lib/python3.11/site-packages/pendulum/parser.py", line 29, in parse
    return _parse(text, **options)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/santhoshsolomon/Desktop/venv/lib/python3.11/site-packages/pendulum/parser.py", line 45, in _parse
    parsed = base_parse(text, **options)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/santhoshsolomon/Desktop/venv/lib/python3.11/site-packages/pendulum/parsing/__init__.py", line 74, in parse
    return _normalize(_parse(text, **_options), **_options)
                      ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/santhoshsolomon/Desktop/venv/lib/python3.11/site-packages/pendulum/parsing/__init__.py", line 128, in _parse
    raise ParserError("Unable to parse string [{}]".format(text))
pendulum.parsing.exceptions.ParserError: Unable to parse string [june 15,1987]

When pendulum parser is failing, I have tried with other underlying tools, dateparser and python-dateutils.

>>> from dateparser import parse as dp_parse
>>> dt = "june 15,1987"
>>> dp_parse(dt)
datetime.datetime(1987, 6, 15, 0, 0) # correct value
>>> from dateutil.parser import parse as du_parse
>>> du_parse(dt)
datetime.datetime(2023, 6, 15, 0, 0) # wrong value

So the issue is happening at fallback parser python-dateutil.

Library versions

>>>
>>> import maya
>>> print(maya.__version__)
0.6.1
>>> import dateutil
>>> print(dateutil.__version__)
2.8.2
>>> import dateparser
>>> print(dateparser.__version__)
1.2.0
>>> import pendulum
>>> print(pendulum.__version__)
2.1.2

Added upstream issue at

• dateutils - Wrong parsing - june 15,1987 to datetime.datetime(2023, 6, 15, 0, 0) dateutil/dateutil#1321
• pendulum - Breaking parser - june 15, 1987 python-pendulum/pendulum#770