[BUG] DeprecationWarning: Parsing dates involving a day of month without a year specified is ambiguious and fails to parse leap day.

[ThatIsAPseudo]

Describe your context
Please provide us your environment, so we can easily reproduce the issue.

• replace the result of pip list | grep dash below

dash                           3.0.4

Describe the bug

When importing dash :

DeprecationWarning: Parsing dates involving a day of month without a year specified is ambiguious
and fails to parse leap day. The default behavior will change in Python 3.15
to either always raise an exception or to use a different default year (TBD).
To avoid trouble, add a specific year to the input & format.
See https://github.com/python/cpython/issues/70647.
  import dash

Expected behavior

No deprecation warning should occur.
The surprising part is that when I search for "strptime" in the dash repository, Github doesn't return any result.

[T4rk1n]

I don't think we actually use any date stuff directly beside our tests. Was there any more output below the import dash and what was the Python version ?

[ThatIsAPseudo]

Here is the whole script :

Python 3.13.3 | packaged by conda-forge | (main, Apr 14 2025, 20:44:30) [Clang 18.1.8 ] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import dash
<python-input-0>:1: DeprecationWarning: Parsing dates involving a day of month without a year specified is ambiguious
and fails to parse leap day. The default behavior will change in Python 3.15
to either always raise an exception or to use a different default year (TBD).
To avoid trouble, add a specific year to the input & format.
See https://github.com/python/cpython/issues/70647.
>>>

[T4rk1n]

I cannot reproduce, maybe you have something else in your environment that is triggering the warning.

Do you have any dash_hooks plugin?
What is inside the dash module? (can run dir(dash) to find out)

[ThatIsAPseudo]

Here is the output of dir(dash)
I have indeed _hooks and hooks

>>> dir(dash)
['ALL', 'ALLSMALLER', 'CeleryManager', 'ClientsideFunction', 'Dash', 'DiskcacheManager', 'Input', 'MATCH', 
'Output', 'Patch', 'State', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', 
'__package__', '__path__', '__plotly_dash', '__spec__', '__version__', '_callback', '_callback_context', '_configs', 
'_dash_renderer', '_get_app', '_get_paths', '_grouping', '_hooks', '_jupyter', '_jupyter_nbextension_paths', 
'_obsolete', '_pages', '_patch', '_utils', '_validate', '_watch', 'background_callback', 'callback', 'callback_context', 
'clientside_callback', 'ctx', 'dash', 'dash_table', 'dcc', 'dependencies', 'development', 'exceptions', 'fingerprint', 
'get_app', 'get_asset_url', 'get_relative_path', 'hooks', 'html', 'jupyter_dash', 'no_update', 'page_container', 
'page_registry', 'register_page', 'resources', 'set_props', 'strip_relative_path', 'types', 'version']