[FR] Better support for pathlib.Path in other fields

[Laurent2916]

Proposal Summary

Currently pathlib.Path is well supported for the filepath field, though not so much for other fields:

$ python
Python 3.12.7 (main, Oct 16 2024, 04:37:19) [Clang 18.1.8 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import fiftyone as fo
>>> from pathlib import Path
>>> d = fo.Dataset("my_dataset_test")

>>> s1 = fo.Sample(filepath="/foo/bar")
>>> d.add_sample(s1)
'673473ebe4b27ccbe9f5016d'

>>> s2 = fo.Sample(filepath=Path("/foo/bar"))
>>> d.add_sample(s2)
'673473f9e4b27ccbe9f5016e'

>>> s3 = fo.Sample(filepath=Path("/foo/bar"), other_filepath="/bar/foo")
>>> d.add_sample(s3)
'67347412e4b27ccbe9f5016f'

>>> s4 = fo.Sample(filepath=Path("/foo/bar"), other_filepath=Path("/bar/foo"))
>>> d.add_sample(s4)
Traceback (most recent call last):
  File "/blabla/.venv/lib/python3.12/site-packages/fiftyone/core/dataset.py", line 7950, in _validate_samples
    field.validate(value)
  File "/blabla/.venv/lib/python3.12/site-packages/mongoengine/fields.py", line 129, in validate
    self.error("StringField only accepts string values")
  File "/blabla/.venv/lib/python3.12/site-packages/mongoengine/base/fields.py", line 171, in error
    raise ValidationError(message, errors=errors, field_name=field_name)
mongoengine.errors.ValidationError: StringField only accepts string values

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/blabla/.venv/lib/python3.12/site-packages/fiftyone/core/dataset.py", line 3201, in add_sample
    ids = self._add_samples_batch(
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/blabla/.venv/lib/python3.12/site-packages/fiftyone/core/dataset.py", line 3323, in _add_samples_batch
    self._validate_samples(samples)
  File "/blabla/.venv/lib/python3.12/site-packages/fiftyone/core/dataset.py", line 7952, in _validate_samples
    raise ValueError(
ValueError: Invalid value for field 'other_filepath'. Reason: StringField only accepts string values

>>> s4
<Sample: {
    'id': None,
    'media_type': 'image',
    'filepath': '/foo/bar',  # <-- the Path was converted to str
    'tags': [],
    'metadata': None,
    'created_at': None,
    'last_modified_at': None,
    'other_filepath': PosixPath('/bar/foo'),  # <-- PosixPath not converted to str
}>

>>> s5 = fo.Sample(filepath=Path("/foo/bar"), other_filepath=str(Path("/bar/foo")))
>>> d.add_sample(s5)
'6734743ee4b27ccbe9f50170'

The workaround is to wrap every Path with str(..), though if this could be handled directly this would be better.

What areas of FiftyOne does this feature affect?

• App: FiftyOne application
• Core: Core fiftyone Python library
• Server: FiftyOne server

Willingness to contribute

The FiftyOne Community welcomes contributions! Would you or another member of your organization be willing to contribute an implementation of this feature?

• Yes. I can contribute this feature independently
• Yes. I would be willing to contribute this feature with guidance from the FiftyOne community
• No. I cannot contribute this feature at this time