feat: reads using global ctx

[ion-elgreco]

Which issue does this PR close?

• closes Make all read methods available on DataFusion module #918

[kylebarron]

Side note: it would be great to use ruff (https://stackoverflow.com/a/77876298) or isort to deterministically and programmatically sort python imports, and validate that in CI. I think isort/ruff would have a newline here between the third-party and first-party imports.

[kevinjqliu]

there a pre-commit config for ruff linter and formatter

datafusion-python/.pre-commit-config.yaml

Lines 23 to 30 in 79c22d6

	- repo: https://github.com/astral-sh/ruff-pre-commit
	# Ruff version.
	rev: v0.3.0
	hooks:
	# Run the linter.
	- id: ruff
	# Run the formatter.
	- id: ruff-format

[kylebarron]

As the SO answer above explains, import sorting isn't currently part of the default ruff-format behavior. We'd need to opt-in by adding an I element here:

datafusion-python/pyproject.toml

Line 66 in 79c22d6

select = ["E4", "E7", "E9", "F", "D", "W"]

[timsaucer]

I'm not opposed to this addition, but there is a potential source of confusion that we can mitigate with documentation. If a new user creates a session context themself and registers functions, and then creates a dataframe using this method, the functions they registered will not be available. I think it could lead to a fair amount of confusion.

I think this is easily mitigated by adding documentation to these functions that describes that it uses a default global session context and if the user needs a custom context they need to use the functions .