PEP 604 and line breaks #2316

srittau · 2021-06-08T12:17:09Z

Describe the style change

Long PEP 604 annotations (X | Y) in function definitions (and probably other contexts) are currently broken into multiple lines without extra indentation. This makes it hard to recognize the arguments in the signature. My suggestion would be to treat those annotations similar to regular bitwise or operators inside type annotations: Indent followup lines and possibly use parentheses.

Examples in the current Black style

def foo(
    i: int,
    x: Loooooooooooooooooooooooong
    | Looooooooooooooooong
    | Looooooooooooooooooooong
    | Looooooong,
    *,
    s: str
) -> None:
    pass

A practical example (with shorter line width):

def create_medical_record_entries(
    context: RequestContext,
    db_entries: Iterable[CharlyMedicalRecordEntry]
    | Iterable[CharlyLabRecordEntry],
    *,
    ignore_signs: bool = True
) -> list[MedicalRecordEntry]:
    ...

Desired style (without extra arguments)

def foo(
    x: (
        Loooooooooooooooooooooooong
        | Looooooooooooooooong
        | Looooooooooooooooooooong
        | Looooooong
    ),
) -> None:
    pass

Or maybe:

def foo(
    x:
        Loooooooooooooooooooooooong
        | Looooooooooooooooong
        | Looooooooooooooooooooong
        | Looooooong,
) -> None:
    pass

Or:

def foo(
    x: Loooooooooooooooooooooooong
        | Looooooooooooooooong
        | Looooooooooooooooooooong
        | Looooooong,
) -> None:
    pass

The text was updated successfully, but these errors were encountered:

srittau · 2021-06-08T12:21:28Z

Options 2 or 3 would only work within function defs, not in variable annotations, though.

felix-hilden · 2021-06-08T12:33:21Z

To me 1 and 3 look good, 2 is a bit weird. But I agree variable annotations should work similarly.

srittau · 2021-06-08T13:05:44Z

Option 3 looks clearer to me in function annotations, but I don't know if there should be separate styles for function arguments and other annotations.

Zeta611 · 2022-01-08T03:38:14Z

Current Black line-break is awkward with a short type hinting with a long default value as well:

@app.get("/path/")
async def foo(
    q: str
    | None = Query(None, title="Some long title", description="Some long description")
):
    pass

IMHO the following is better:

@app.get("/path/")
async def foo(
    q: str | None = Query(
        None, title="Some long title", description="Some long description"
    )
):
    pass

It is how it is done without the type annotation.

MarcDufresne · 2022-04-19T14:16:52Z

Any progress or solution on this? We are facing this issue now that we are switching to Python 3.10.

ichard26 · 2022-04-19T14:51:34Z

None as far as I am aware.

johnthagen · 2022-12-12T20:02:37Z

We've begun porting our type annotations to Python 3.10+ | unions, and we have hit this as well. It really decreases readability compared to how Black formats Optional[T], hiding type information on another line. Here's a small snippet from a Typer CLI app:

def f(
    max_jobs: int
    | None = Option(
        None, help="Maximum number of jobs to launch."
    ),

@Zeta611's suggestion is what we were going to propose as well.

EnderASz · 2023-06-06T11:48:48Z

Hey, I see Release 23.1.0 is assigned here, but this update was a bit time ago.
Is there any progress?
I'm working with some FastAPI project right now, and this issue seems to be the only thing really really stopping me from using Black.

jakkdl · 2023-09-17T11:24:01Z

I've started looking at this - sharing some WIP thoughts:

compared to variable annotations

variable annotations have to include parentheses (because you cannot write inline annotations, e.g. (x: int, y: float) = (3, 3.7) is illegal, walrus expressions also cannot be annotated), which is a pretty decent reason to differentiate the formatting between them. They're currently formatted as:

z: (
    Loooooooooooooooooooooooong
    | Loooooooooooooooooooooooong
    | Loooooooooooooooooooooooong
    | Loooooooooooooooooooooooong
)

So a relatively straightforward implementation would be to do option 1 (I'm confused why @srittau says it won't work in variable annotations), but we're adding two unnecessary lines - so IMO option 3 is the superior one.

other scenarios not specific to pep604

I tried to come up with scenarios where you get the same behavior without being in a function definition, or where the | is wrapped in parentheses, and I'm pretty sure this is the exact same problem popping up:

x = (
    z
    == 9999999999999999999999999999999999999999
    | 9999999999999999999999999999999999999999
    | 9999999999999999999999999999999999999999
    | 9999999999999999999999999999999999999999,
    y
    != 9999999999999999999999999999999999999999
    + 9999999999999999999999999999999999999999
    + 9999999999999999999999999999999999999999
    + 9999999999999999999999999999999999999999,
)

which probably should be formatted as

x = (
    z == 9999999999999999999999999999999999999999
        | 9999999999999999999999999999999999999999
        | 9999999999999999999999999999999999999999
        | 9999999999999999999999999999999999999999,
    y != 9999999999999999999999999999999999999999
        + 9999999999999999999999999999999999999999
        + 9999999999999999999999999999999999999999
        + 9999999999999999999999999999999999999999,
)

implementation

Going with option 1, we'd insert brackets whenever encountering this situation - but I think even with option 3 the best way to implement it within the current logic is to add a special pair of "invisible" brackets so the logic for indenting and nested brackets (be they "real" or not) and similar can be reused.

srittau · 2023-09-17T11:36:08Z

So a relatively straightforward implementation would be to do option 1 (I'm confused why @srittau says it won't work in variable annotations), but we're adding two unnecessary lines - so IMO option 3 is the superior one.

Option 1 works in variable annotations, options 2 and 3 don't, because of the missing parentheses.

jakkdl · 2023-09-17T11:37:12Z

So a relatively straightforward implementation would be to do option 1 (I'm confused why @srittau says it won't work in variable annotations), but we're adding two unnecessary lines - so IMO option 3 is the superior one.

Option 1 works in variable annotations, options 2 and 3 don't, because of the missing parentheses.

Ah sorry, I misinterpreted it as you saying the other way around. 👍

Zac-HD · 2023-09-25T16:23:34Z

I really like the (preview) style changes from #3899

╭──────────────────────── Summary ────────────────────────╮
│ 3 projects & 15 files changed / 279 changes [+138/-141] │
│                                                         │
│ ... out of 2 489 089 lines, 11 731 files & 23 projects  │
╰─────────────────────────────────────────────────────────╯

[pandas - https://github.com/pandas-dev/pandas.git]
╰─> revision c4efa9203ef7e13a797058600010876fdee7eee6
--- a/pandas:pandas/_libs/json.pyi
+++ b/pandas:pandas/_libs/json.pyi
@@ -9,12 +9,13 @@
     double_precision: int = ...,
     indent: int = ...,
     orient: str = ...,
     date_unit: str = ...,
     iso_dates: bool = ...,
-    default_handler: None
-    | Callable[[Any], str | float | bool | list | dict | None] = ...,
+    default_handler: (
+        None | Callable[[Any], str | float | bool | list | dict | None]
+    ) = ...,
 ) -> str: ...
 def ujson_loads(
     s: str,
     precise_float: bool = ...,
     numpy: bool = ...,

--- a/pandas:pandas/core/generic.py
+++ b/pandas:pandas/core/generic.py
@@ -2368,12 +2368,13 @@
         compression_options=_shared_docs["compression_options"] % "path_or_buf",
     )
     def to_json(
         self,
         path_or_buf: FilePath | WriteBuffer[bytes] | WriteBuffer[str] | None = None,
-        orient: Literal["split", "records", "index", "table", "columns", "values"]
-        | None = None,
+        orient: (
+            Literal["split", "records", "index", "table", "columns", "values"] | None
+        ) = None,
         date_format: str | None = None,
         double_precision: int = 10,
         force_ascii: bool_t = True,
         date_unit: TimeUnit = "ms",
         default_handler: Callable[[Any], JSONSerializable] | None = None,

--- a/pandas:pandas/core/resample.py
+++ b/pandas:pandas/core/resample.py
@@ -2063,12 +2063,14 @@
         axis: Axis = 0,
         fill_method=None,
         limit: int | None = None,
         kind: str | None = None,
         convention: Literal["start", "end", "e", "s"] | None = None,
-        origin: Literal["epoch", "start", "start_day", "end", "end_day"]
-        | TimestampConvertibleTypes = "start_day",
+        origin: (
+            Literal["epoch", "start", "start_day", "end", "end_day"]
+            | TimestampConvertibleTypes
+        ) = "start_day",
         offset: TimedeltaConvertibleTypes | None = None,
         group_keys: bool = False,
         **kwargs,
     ) -> None:
         # Check for correctness of the keyword arguments which would

--- a/pandas:pandas/core/tools/timedeltas.py
+++ b/pandas:pandas/core/tools/timedeltas.py
@@ -69,20 +69,22 @@
     errors: DateTimeErrorChoices = ...,
 ) -> TimedeltaIndex: ...
 
 
 def to_timedelta(
-    arg: str
-    | int
-    | float
-    | timedelta
-    | list
-    | tuple
-    | range
-    | ArrayLike
-    | Index
-    | Series,
+    arg: (
+        str
+        | int
+        | float
+        | timedelta
+        | list
+        | tuple
+        | range
+        | ArrayLike
+        | Index
+        | Series
+    ),
     unit: UnitChoices | None = None,
     errors: DateTimeErrorChoices = "raise",
 ) -> Timedelta | TimedeltaIndex | Series:
     """
     Convert argument to timedelta.

--- a/pandas:pandas/io/excel/_base.py
+++ b/pandas:pandas/io/excel/_base.py
@@ -387,16 +387,13 @@
     sheet_name: str | int = ...,
     *,
     header: int | Sequence[int] | None = ...,
     names: list[str] | None = ...,
     index_col: int | Sequence[int] | None = ...,
-    usecols: int
-    | str
-    | Sequence[int]
-    | Sequence[str]
-    | Callable[[str], bool]
-    | None = ...,
+    usecols: (
+        int | str | Sequence[int] | Sequence[str] | Callable[[str], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: Literal["xlrd", "openpyxl", "odf", "pyxlsb", "calamine"] | None = ...,
     converters: dict[str, Callable] | dict[int, Callable] | None = ...,
     true_values: Iterable[Hashable] | None = ...,
     false_values: Iterable[Hashable] | None = ...,
@@ -425,16 +422,13 @@
     sheet_name: list[IntStrT] | None,
     *,
     header: int | Sequence[int] | None = ...,
     names: list[str] | None = ...,
     index_col: int | Sequence[int] | None = ...,
-    usecols: int
-    | str
-    | Sequence[int]
-    | Sequence[str]
-    | Callable[[str], bool]
-    | None = ...,
+    usecols: (
+        int | str | Sequence[int] | Sequence[str] | Callable[[str], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: Literal["xlrd", "openpyxl", "odf", "pyxlsb", "calamine"] | None = ...,
     converters: dict[str, Callable] | dict[int, Callable] | None = ...,
     true_values: Iterable[Hashable] | None = ...,
     false_values: Iterable[Hashable] | None = ...,
@@ -463,16 +457,13 @@
     sheet_name: str | int | list[IntStrT] | None = 0,
     *,
     header: int | Sequence[int] | None = 0,
     names: list[str] | None = None,
     index_col: int | Sequence[int] | None = None,
-    usecols: int
-    | str
-    | Sequence[int]
-    | Sequence[str]
-    | Callable[[str], bool]
-    | None = None,
+    usecols: (
+        int | str | Sequence[int] | Sequence[str] | Callable[[str], bool] | None
+    ) = None,
     dtype: DtypeArg | None = None,
     engine: Literal["xlrd", "openpyxl", "odf", "pyxlsb", "calamine"] | None = None,
     converters: dict[str, Callable] | dict[int, Callable] | None = None,
     true_values: Iterable[Hashable] | None = None,
     false_values: Iterable[Hashable] | None = None,

--- a/pandas:pandas/io/formats/format.py
+++ b/pandas:pandas/io/formats/format.py
@@ -1678,11 +1678,11 @@
         )
         return fmt_values
 
 
 def format_percentiles(
-    percentiles: (np.ndarray | Sequence[float]),
+    percentiles: np.ndarray | Sequence[float],
 ) -> list[str]:
     """
     Outputs rounded and formatted percentiles.
 
     Parameters

--- a/pandas:pandas/io/parsers/readers.py
+++ b/pandas:pandas/io/parsers/readers.py
@@ -634,27 +634,25 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
     skipinitialspace: bool = ...,
     skiprows: list[int] | int | Callable[[Hashable], bool] | None = ...,
     skipfooter: int = ...,
     nrows: int | None = ...,
-    na_values: Hashable
-    | Iterable[Hashable]
-    | Mapping[Hashable, Iterable[Hashable]]
-    | None = ...,
+    na_values: (
+        Hashable | Iterable[Hashable] | Mapping[Hashable, Iterable[Hashable]] | None
+    ) = ...,
     na_filter: bool = ...,
     verbose: bool = ...,
     skip_blank_lines: bool = ...,
     parse_dates: bool | Sequence[Hashable] | None = ...,
     infer_datetime_format: bool | lib.NoDefault = ...,
@@ -695,27 +693,25 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
     skipinitialspace: bool = ...,
     skiprows: list[int] | int | Callable[[Hashable], bool] | None = ...,
     skipfooter: int = ...,
     nrows: int | None = ...,
-    na_values: Hashable
-    | Iterable[Hashable]
-    | Mapping[Hashable, Iterable[Hashable]]
-    | None = ...,
+    na_values: (
+        Hashable | Iterable[Hashable] | Mapping[Hashable, Iterable[Hashable]] | None
+    ) = ...,
     keep_default_na: bool = ...,
     na_filter: bool = ...,
     verbose: bool = ...,
     skip_blank_lines: bool = ...,
     parse_dates: bool | Sequence[Hashable] | None = ...,
@@ -757,27 +753,25 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
     skipinitialspace: bool = ...,
     skiprows: list[int] | int | Callable[[Hashable], bool] | None = ...,
     skipfooter: int = ...,
     nrows: int | None = ...,
-    na_values: Hashable
-    | Iterable[Hashable]
-    | Mapping[Hashable, Iterable[Hashable]]
-    | None = ...,
+    na_values: (
+        Hashable | Iterable[Hashable] | Mapping[Hashable, Iterable[Hashable]] | None
+    ) = ...,
     keep_default_na: bool = ...,
     na_filter: bool = ...,
     verbose: bool = ...,
     skip_blank_lines: bool = ...,
     parse_dates: bool | Sequence[Hashable] | None = ...,
@@ -819,27 +813,25 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
     skipinitialspace: bool = ...,
     skiprows: list[int] | int | Callable[[Hashable], bool] | None = ...,
     skipfooter: int = ...,
     nrows: int | None = ...,
-    na_values: Hashable
-    | Iterable[Hashable]
-    | Mapping[Hashable, Iterable[Hashable]]
-    | None = ...,
+    na_values: (
+        Hashable | Iterable[Hashable] | Mapping[Hashable, Iterable[Hashable]] | None
+    ) = ...,
     keep_default_na: bool = ...,
     na_filter: bool = ...,
     verbose: bool = ...,
     skip_blank_lines: bool = ...,
     parse_dates: bool | Sequence[Hashable] | None = ...,
@@ -892,14 +884,13 @@
     delimiter: str | None | lib.NoDefault = None,
     # Column and Index Locations and Names
     header: int | Sequence[int] | None | Literal["infer"] = "infer",
     names: Sequence[Hashable] | None | lib.NoDefault = lib.no_default,
     index_col: IndexLabel | Literal[False] | None = None,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = None,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = None,
     # General Parsing Configuration
     dtype: DtypeArg | None = None,
     engine: CSVEngine | None = None,
     converters: Mapping[Hashable, Callable] | None = None,
     true_values: list | None = None,
@@ -907,14 +898,13 @@
     skipinitialspace: bool = False,
     skiprows: list[int] | int | Callable[[Hashable], bool] | None = None,
     skipfooter: int = 0,
     nrows: int | None = None,
     # NA and Missing Data Handling
-    na_values: Hashable
-    | Iterable[Hashable]
-    | Mapping[Hashable, Iterable[Hashable]]
-    | None = None,
+    na_values: (
+        Hashable | Iterable[Hashable] | Mapping[Hashable, Iterable[Hashable]] | None
+    ) = None,
     keep_default_na: bool = True,
     na_filter: bool = True,
     verbose: bool = False,
     skip_blank_lines: bool = True,
     # Datetime Handling
@@ -990,14 +980,13 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
@@ -1049,14 +1038,13 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
@@ -1108,14 +1096,13 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
@@ -1167,14 +1154,13 @@
     sep: str | None | lib.NoDefault = ...,
     delimiter: str | None | lib.NoDefault = ...,
     header: int | Sequence[int] | None | Literal["infer"] = ...,
     names: Sequence[Hashable] | None | lib.NoDefault = ...,
     index_col: IndexLabel | Literal[False] | None = ...,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = ...,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = ...,
     dtype: DtypeArg | None = ...,
     engine: CSVEngine | None = ...,
     converters: Mapping[Hashable, Callable] | None = ...,
     true_values: list | None = ...,
     false_values: list | None = ...,
@@ -1239,14 +1225,13 @@
     delimiter: str | None | lib.NoDefault = None,
     # Column and Index Locations and Names
     header: int | Sequence[int] | None | Literal["infer"] = "infer",
     names: Sequence[Hashable] | None | lib.NoDefault = lib.no_default,
     index_col: IndexLabel | Literal[False] | None = None,
-    usecols: list[HashableT]
-    | tuple[HashableT]
-    | Callable[[Hashable], bool]
-    | None = None,
+    usecols: (
+        list[HashableT] | tuple[HashableT] | Callable[[Hashable], bool] | None
+    ) = None,
     # General Parsing Configuration
     dtype: DtypeArg | None = None,
     engine: CSVEngine | None = None,
     converters: Mapping[Hashable, Callable] | None = None,
     true_values: list | None = None,

--- a/pandas:pandas/plotting/_matplotlib/boxplot.py
+++ b/pandas:pandas/plotting/_matplotlib/boxplot.py
@@ -143,14 +143,16 @@
         self._caps_c = colors[0]
 
     def _get_colors(
         self,
         num_colors=None,
-        color_kwds: dict[str, MatplotlibColor]
-        | MatplotlibColor
-        | Collection[MatplotlibColor]
-        | None = "color",
+        color_kwds: (
+            dict[str, MatplotlibColor]
+            | MatplotlibColor
+            | Collection[MatplotlibColor]
+            | None
+        ) = "color",
     ) -> None:
         pass
 
     def maybe_color_bp(self, bp) -> None:
         if isinstance(self.color, dict):

--- a/pandas:typings/numba.pyi
+++ b/pandas:typings/numba.pyi
@@ -13,14 +13,16 @@
 def __getattr__(name: str) -> Any: ...  # incomplete
 @overload
 def jit(signature_or_function: F) -> F: ...
 @overload
 def jit(
-    signature_or_function: str
-    | list[str]
-    | numba.core.types.abstract.Type
-    | list[numba.core.types.abstract.Type] = ...,
+    signature_or_function: (
+        str
+        | list[str]
+        | numba.core.types.abstract.Type
+        | list[numba.core.types.abstract.Type]
+    ) = ...,
     locals: dict = ...,  # TODO: Mapping of local variable names to Numba types
     cache: bool = ...,
     pipeline_class: numba.compiler.CompilerBase = ...,
     boundscheck: bool | None = ...,
     *,


[poetry - https://github.com/python-poetry/poetry.git]
╰─> revision 02140ff4a14aba0ee34dadc003a93aa26afdfebe
--- a/poetry:src/poetry/utils/authenticator.py
+++ b/poetry:src/poetry/utils/authenticator.py
@@ -115,13 +115,13 @@
         self._config = config or Config.create()
         self._io = io
         self._sessions_for_netloc: dict[str, requests.Session] = {}
         self._credentials: dict[str, HTTPAuthCredential] = {}
         self._certs: dict[str, RepositoryCertificateConfig] = {}
-        self._configured_repositories: dict[
-            str, AuthenticatorRepositoryConfig
-        ] | None = None
+        self._configured_repositories: (
+            dict[str, AuthenticatorRepositoryConfig] | None
+        ) = None
         self._password_manager = PasswordManager(self._config)
         self._cache_control = (
             FileCache(
                 str(
                     self._config.repository_cache_directory


[typeshed - https://github.com/python/typeshed.git]
╰─> revision 11e51bef9d0da08c6e766e362a21a9dcf89c5bd9
--- a/typeshed:stdlib/pyexpat/__init__.pyi
+++ b/typeshed:stdlib/pyexpat/__init__.pyi
@@ -50,13 +50,16 @@
     XmlDeclHandler: Callable[[str, str | None, int], Any] | None
     StartDoctypeDeclHandler: Callable[[str, str | None, str | None, bool], Any] | None
     EndDoctypeDeclHandler: Callable[[], Any] | None
     ElementDeclHandler: Callable[[str, _Model], Any] | None
     AttlistDeclHandler: Callable[[str, str, str, str | None, bool], Any] | None
-    StartElementHandler: Callable[[str, dict[str, str]], Any] | Callable[[str, list[str]], Any] | Callable[
-        [str, dict[str, str], list[str]], Any
-    ] | None
+    StartElementHandler: (
+        Callable[[str, dict[str, str]], Any]
+        | Callable[[str, list[str]], Any]
+        | Callable[[str, dict[str, str], list[str]], Any]
+        | None
+    )
     EndElementHandler: Callable[[str], Any] | None
     ProcessingInstructionHandler: Callable[[str, str], Any] | None
     CharacterDataHandler: Callable[[str], Any] | None
     UnparsedEntityDeclHandler: Callable[[str, str | None, str, str | None, str], Any] | None
     EntityDeclHandler: Callable[[str, bool, str | None, str | None, str, str | None, str | None], Any] | None

--- a/typeshed:stubs/influxdb-client/influxdb_client/client/write_api.pyi
+++ b/typeshed:stubs/influxdb-client/influxdb_client/client/write_api.pyi
@@ -83,23 +83,25 @@
     ) -> None: ...
     def write(
         self,
         bucket: str,
         org: str | None = None,
-        record: str
-        | Iterable[str]
-        | Point
-        | Iterable[Point]
-        | dict[Incomplete, Incomplete]
-        | Iterable[dict[Incomplete, Incomplete]]
-        | bytes
-        | Iterable[bytes]
-        | _Observable
-        | _NamedTuple
-        | Iterable[_NamedTuple]
-        | _DataClass
-        | Iterable[_DataClass] = None,
+        record: (
+            str
+            | Iterable[str]
+            | Point
+            | Iterable[Point]
+            | dict[Incomplete, Incomplete]
+            | Iterable[dict[Incomplete, Incomplete]]
+            | bytes
+            | Iterable[bytes]
+            | _Observable
+            | _NamedTuple
+            | Iterable[_NamedTuple]
+            | _DataClass
+            | Iterable[_DataClass]
+        ) = None,
         write_precision: _WritePrecision = "ns",
         **kwargs,
     ) -> Any: ...
     def flush(self) -> None: ...
     def close(self) -> None: ...

--- a/typeshed:stubs/influxdb-client/influxdb_client/client/write_api_async.pyi
+++ b/typeshed:stubs/influxdb-client/influxdb_client/client/write_api_async.pyi
@@ -[17](https://github.com/psf/black/actions/runs/6275527706/job/17044773640#step:10:18),20 +17,22 @@
     def __init__(self, influxdb_client, point_settings: PointSettings = ...) -> None: ...
     async def write(
         self,
         bucket: str,
         org: str | None = None,
-        record: str
-        | Iterable[str]
-        | Point
-        | Iterable[Point]
-        | dict[Incomplete, Incomplete]
-        | Iterable[dict[Incomplete, Incomplete]]
-        | bytes
-        | Iterable[bytes]
-        | _NamedTuple
-        | Iterable[_NamedTuple]
-        | _DataClass
-        | Iterable[_DataClass] = None,
+        record: (
+            str
+            | Iterable[str]
+            | Point
+            | Iterable[Point]
+            | dict[Incomplete, Incomplete]
+            | Iterable[dict[Incomplete, Incomplete]]
+            | bytes
+            | Iterable[bytes]
+            | _NamedTuple
+            | Iterable[_NamedTuple]
+            | _DataClass
+            | Iterable[_DataClass]
+        ) = None,
         write_precision: _WritePrecision = "ns",
         **kwargs,
     ) -> bool: ...

--- a/typeshed:stubs/openpyxl/openpyxl/chart/axis.pyi
+++ b/typeshed:stubs/openpyxl/openpyxl/chart/axis.pyi
@@ -153,14 +153,13 @@
     extLst: Typed[ExtensionList, Literal[True]]
     __elements__: ClassVar[tuple[str, ...]]
     def __init__(
         self,
         custUnit: _HasTagAndGet[_ConvertibleToFloat | None] | _ConvertibleToFloat | None = None,
-        builtInUnit: _HasTagAndGet[_DisplayUnitsLabelListBuiltInUnit]
-        | _DisplayUnitsLabelListBuiltInUnit
-        | Literal["none"]
-        | None = None,
+        builtInUnit: (
+            _HasTagAndGet[_DisplayUnitsLabelListBuiltInUnit] | _DisplayUnitsLabelListBuiltInUnit | Literal["none"]
| None
+        ) = None,
         dispUnitsLbl: DisplayUnitsLabel | None = None,
         extLst: Unused = None,
     ) -> None: ...
 
 class NumericAxis(_BaseAxis):

--- a/typeshed:stubs/openpyxl/openpyxl/packaging/custom.pyi
+++ b/typeshed:stubs/openpyxl/openpyxl/packaging/custom.pyi
@@ -24,13 +24,[18](https://github.com/psf/black/actions/runs/6275527706/job/17044773640#step:10:19) @@
 class NestedBoolText(Bool[Incomplete], NestedText[Incomplete, Incomplete]): ...  # type: ignore[misc]
 
 class _TypedProperty(Strict, Generic[_T]):
     name: String[Literal[False]]
     # Since this is internal, just list all possible values
-    value: Integer[Literal[False]] | Float[Literal[False]] | String[Literal[True]] | DateTime[Literal[False]] | 
Bool[
-        Literal[False]
-    ] | String[Literal[False]]
+    value: (
+        Integer[Literal[False]]
+        | Float[Literal[False]]
+        | String[Literal[True]]
+        | DateTime[Literal[False]]
+        | Bool[Literal[False]]
+        | String[Literal[False]]
+    )
     def __init__(self, name: str, value: _T) -> None: ...
     def __eq__(self, other: _TypedProperty[Any]) -> bool: ...  # type: ignore[override]
 
 class IntProperty(_TypedProperty[_ConvertibleToInt]):
     value: Integer[Literal[False]]

That's essentially option (1) above - it has the advantages of being easy to implement (and indeed implemented), working well with default values, and consistency with variable annotations (though IMO this is a minor concern at most). My favorite style is actually option (3), which omits the parens - but it's unclear what should happen when there's a default value.

def foo(
    # with no default value, this looks great
    required: Loooooooooooooooooooooooong
        | Looooooooooooooooong,
    # but with defaults it seems unsatisfying
    inline: Loooooooooooooooooooooooong
        | Looooooooooooooooong = value,  # easy to miss this!
    nextline: Loooooooooooooooooooooooong
        | Looooooooooooooooong
        = value,  # best IMO, maybe still confusable?
    withparens: (
        Loooooooooooooooooooooooong
        | Looooooooooooooooong
    ) = value,  # fine in isolation, awfully inconsistent though
) -> None:
    ...

I propose that we either stick with the parens-using new status quo, or adopt the nextline formatting above, and either way close this issue for good before the next style update / major version.

Please comment, or react ❤️ for "keep status-quo parens", or 🚀 for "change and use nextline".

jakkdl · 2023-10-09T11:41:50Z

After implementing nextline in #3930 and seeing diffs on real live code we agreed that it in fact was not an improvement in the majority of cases, so we can close this issue as resolved as of #3899, that resolved this in "style 1" with parentheses.

srittau · 2023-10-09T16:06:40Z

Thanks everyone, and especially @jakkdl for making this happen!

tekumara · 2023-11-28T09:04:57Z

ICYMI like I did, for short type hints, eg:

@app.get("/path/")
async def foo(
    q: str
    | None = Query(None, title="Some long title", description="Some long description")
):
    pass

you can now add parens around the argument type hints to get this:

@app.get("/path/")
async def foo(
    q: (str | None) = Query(
        None, title="Some long title", description="Some long description")
):
    pass

jakkdl · 2023-11-28T13:50:00Z

@tekumara you can get that automatically by running black with --preview to enable the fixes from #3899

felix-hilden added F: linebreak How should we split up lines? F: parentheses Too many parentheses, not enough parentheses, and so on. T: style What do we want Blackened code to look like? labels Jun 8, 2021

JelleZijlstra mentioned this issue Jan 12, 2022

Black inconsistent about arguments with many alternative types #2767

Closed

Illviljan mentioned this issue Jan 12, 2022

Add pyupgrade onto pre-commit pydata/xarray#6152

Merged

1 task

JelleZijlstra mentioned this issue Jan 29, 2022

Don't split type annotation with alternative union syntax #2038

Closed

ichard26 mentioned this issue Sep 28, 2022

Black formats union arguments with default call value weirdly #3296

Closed

calumy mentioned this issue Sep 30, 2022

Unnecessary linebreak on 3.10-style Union types. #3301

Closed

This was referenced Oct 8, 2022

Black collapses lists in return type annotations onto one line, regardless of the "magic" trailing comma. #3018

Closed

Avoid needless linebreaks on | in PEP-604 type annotations #3319

Closed

ichard26 added this to the Release 23.1.0 milestone Oct 9, 2022

yilei mentioned this issue Apr 26, 2023

Ugly line splitting for 3.10+ union type hints #3649

Closed

JelleZijlstra mentioned this issue Jul 27, 2023

Black breaks lines in type hints that use '|' operator. #3816

Closed

JelleZijlstra mentioned this issue Sep 10, 2023

Don't wrap | None on a new line #3874

Closed

jakkdl mentioned this issue Sep 20, 2023

fix indentation of line breaks in long type hints by adding parens #3899

Merged

3 tasks

jakkdl mentioned this issue Oct 7, 2023

split long function parameter type hints without parentheses #3930

Closed

3 tasks

JelleZijlstra closed this as completed Oct 9, 2023

jakkdl mentioned this issue Dec 22, 2023

Preview style feedback: Parenthesizing long dict, conditional, and type annotations #4123

Open

hauntsaninja mentioned this issue Jan 11, 2024

"More concise formatting for dummy implementations" can be less concise #3872

Closed

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PEP 604 and line breaks #2316

PEP 604 and line breaks #2316

srittau commented Jun 8, 2021

srittau commented Jun 8, 2021

felix-hilden commented Jun 8, 2021

srittau commented Jun 8, 2021

Zeta611 commented Jan 8, 2022 •

edited

MarcDufresne commented Apr 19, 2022

ichard26 commented Apr 19, 2022

johnthagen commented Dec 12, 2022 •

edited

EnderASz commented Jun 6, 2023

jakkdl commented Sep 17, 2023

srittau commented Sep 17, 2023

jakkdl commented Sep 17, 2023

Zac-HD commented Sep 25, 2023

jakkdl commented Oct 9, 2023 •

edited

srittau commented Oct 9, 2023

tekumara commented Nov 28, 2023

jakkdl commented Nov 28, 2023

PEP 604 and line breaks #2316

PEP 604 and line breaks #2316

Comments

srittau commented Jun 8, 2021

srittau commented Jun 8, 2021

felix-hilden commented Jun 8, 2021

srittau commented Jun 8, 2021

Zeta611 commented Jan 8, 2022 • edited

MarcDufresne commented Apr 19, 2022

ichard26 commented Apr 19, 2022

johnthagen commented Dec 12, 2022 • edited

EnderASz commented Jun 6, 2023

jakkdl commented Sep 17, 2023

compared to variable annotations

other scenarios not specific to pep604

implementation

srittau commented Sep 17, 2023

jakkdl commented Sep 17, 2023

Zac-HD commented Sep 25, 2023

jakkdl commented Oct 9, 2023 • edited

srittau commented Oct 9, 2023

tekumara commented Nov 28, 2023

jakkdl commented Nov 28, 2023

Zeta611 commented Jan 8, 2022 •

edited

johnthagen commented Dec 12, 2022 •

edited

jakkdl commented Oct 9, 2023 •

edited