Line too long: Attribute chain on right-hand side

[joaoe]

Issue code (assume max line length <= 80):

    self.some_long_variable_name.some_property_name = self.some_other_property_name.some_long_value
    self.some_long_variable_name.some_property_name = self.some_other_property_name.some_long_method(some_parameter)

Black indents this as

    self.some_long_variable_name.some_property_name = self.some_other_property_name.some_long_value
    self.some_long_variable_name.some_property_name = self.some_other_property_name.some_long_method(
        some_parameter
    )

However, that first line still violates the line length limit.

Suggestion: use parenthesis:

    self.some_long_variable_name.some_property_name = (
        self.some_other_property_name.some_long_value
    )
    self.some_long_variable_name.some_property_name = (
        self.some_other_property_name.some_long_method(some_parameter)
    )

[Paul-Aime]

To add on this, I have a similar case, where this:

da_outliers_loc = (
    (ds.precipitation > ds_qt.precipitation.sel(quantile=qt_values[0])) &
    (ds.temperature > ds_qt.temperature.sel(quantile=qt_values[1]))
)

is formatted like this: (tested in the black playground)

da_outliers_loc = (
    ds.precipitation > ds_qt.precipitation.sel(quantile=qt_values[0])
) & (ds.temperature > ds_qt.temperature.sel(quantile=qt_values[1]))

which is arguably uglier.

[Dr-Irv]

Here's another example (taken from a colleagues' code - I renamed variables):

def outerfunc1(something):
    def outerfunc2(something_else):
        def innerfunc(another_thing):
            for row in another_thing.itertuples():
                try:
                    this_is_a_very_long_variablename = another_thing.sample(n=10)
                    this_is_a_very_long_variablename = this_is_a_very_long_variablename.loc[
                        this_is_a_very_long_variablename.a_pandas_long_column_nam.cumsum()
                        <= 10
                    ]
                except Exception:
                    raise ValueError("something")

could be reformatted as

def outerfunc1(something):
    def outerfunc2(something_else):
        def innerfunc(another_thing):
            for row in another_thing.itertuples():
                try:
                    this_is_a_very_long_variablename = another_thing.sample(n=10)
                    this_is_a_very_long_variablename = (
                        this_is_a_very_long_variablename.loc[
                            this_is_a_very_long_variablename.a_pandas_long_column_nam
                            .cumsum()
                            <= 10
                        ]
                    )
                except Exception:
                    raise ValueError("something")

[yilei]

Triaging comments:

1. Example from OP Line too long: Attribute chain on right-hand side #1525 (comment) is already fixed: playground link.
2. Second example is a dup of Use optional parentheses more often #2156.
3. I'm not sure third example is better, at least it's not related to OP.

[Dr-Irv]

3. I'm not sure third example is better, at least it's not related to OP.

Should I create a new issue for that?

[JelleZijlstra]

I think #510 is enough and this one doesn't need to be kept open.