Formatter collapses last call in call chaining

[cnpryer]

I prefer the change, but reporting since it's a diff in a from-black migration.

Line-length: 88

Related: #5343

Black (23.7.0):

df.drop(
    columns=["aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"]
).drop_duplicates().rename(
    columns={
        "a": "a",
    }
).to_csv(
    path / "aaaaaa.csv", index=False
)

Ruff (0.0.287):

df.drop(
    columns=["aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"]
).drop_duplicates().rename(
    columns={
        "a": "a",
    }
).to_csv(path / "aaaaaa.csv", index=False)

Counter example

df.drop(
    columns=["aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"]
).drop_duplicates(a).rename(
    columns={
        "a": "a",
    }
).to_csv(
    path / "aaaaaa.csv", index=False
).other(a)

Playground: https://play.ruff.rs/02424913-15b0-4703-8eb8-6bc5896b00b6

[MichaReiser]

Black uses Ruff's formatting in preview style if the left is a multiline string but it seems they keep the old formatting otherwise playground

To me it's unclear if expanding the last call is intentional to improve readability. I'm inclined to keep Ruff's formatting because it achieves the goal of avoiding unnecessary horizontal lines but it depends on how frequent we run into this difference (although could be hard to fix)

[cnpryer]

This was not frequent for me, but tbh I'm curious why. The pattern looks like it could be in some exploratory scripts we have.

I'll dig more next week.

[charliermarsh]

We're going to mark this as a known deviation for now. We'll revisit based on user feedback, but it's not blocking for the beta. (We can close the issue itself for now once this is documented.)