python-dotenv should be optional

[maxzhenzhera]

From pyproject.toml:

requires-python = '>=3.7'
dependencies = [
    'pydantic>=2.0.1',
    'python-dotenv>=0.21.0',
]
dynamic = ['version']

python-dotenv is always installed.

From pydantic_settings.sources:

pydantic-settings/pydantic_settings/sources.py

Lines 620 to 632 in 919a20b

	def read_env_file(
	file_path: Path, *, encoding: str | None = None, case_sensitive: bool = False
	) -> Mapping[str, str | None]:
	try:
	from dotenv import dotenv_values
	except ImportError as e:
	raise ImportError('python-dotenv is not installed, run `pip install pydantic[dotenv]`') from e
	file_vars: dict[str, str | None] = dotenv_values(file_path, encoding=encoding or 'utf8')
	if not case_sensitive:
	return {k.lower(): v for k, v in file_vars.items()}
	else:
	return file_vars

• here is the logic of the optional python-dotenv
• and the wrong message in exception to install as pydantic extra (which already does not have this extra)

---

One more place where the project depends on python-dotenv is tests.test_settings:

pydantic-settings/tests/test_settings.py

Lines 39 to 42 in 919a20b

	try:
	import dotenv
	except ImportError:
	dotenv = None

But even here checks are made to skip tests if python-dotenv is not installed (one of the tests with such a check):

pydantic-settings/tests/test_settings.py

Lines 663 to 680 in 919a20b

	@pytest.mark.skipif(not dotenv, reason='python-dotenv not installed')
	def test_env_file_config(env, tmp_path):
	p = tmp_path / '.env'
	p.write_text(test_env_file)
	class Settings(BaseSettings):
	a: str
	b: str
	c: str
	model_config = SettingsConfigDict(env_file=p)
	env.set('A', 'overridden var')
	s = Settings()
	assert s.a == 'overridden var'
	assert s.b == 'better string'
	assert s.c == 'best string'

While making PR I understood the reason for making it in tests.
Finally, I changed the CI workflow.

Selected Assignee: @dmontagu

[samuelcolvin]

Why not keep python-dotenv as required dependency and remove the error handling?

I mean it was different before where pydantic was used for many applications which didn't require use of Settings.

If there's a good reason to make it optional, I'd be happy to consider it - but my first reaction is that the requirement should not be optional and we just change the code that assumes it is.

[maxzhenzhera]

Personally, I do not use .env files.
So, I never load it using pydantic-settings and therefore code that depends on python-dotenv is never executed.

Yep, obviously, I can not say that python-dotenv is kind of heavy dependency and it bothers me.
Just in my case, it is unused and without it, my dependencies will become a little bit cleaner.

[hramezani]

related code for optional dotenv removed at 0226fe2