Openpyxl iter_rows is no more compatible with next function

[mutricyl]

The following was fine with mypy until types-openpyxl-3.1.5.20241114:

next(wb[sheet].iter_rows(...)

But when I upgraded to types-openpyxl-3.1.5.20241126 I have the following error:

error: Argument 1 to "next" has incompatible type "Generator[tuple[Cell | MergedCell, ...], None, None] | Generator[tuple[str | float | datetime | None, ...], None, None]"; expected "SupportsNext[tuple[str | float | datetime | int | None | Cell, ...]]"  [arg-type]

I do not understand why a Generator is not considered as SupportsNext ?

[mutricyl]

looks like commit 82b5fcc is the culprit. Any thought @Avasam ?

[Avasam]

@mutricyl Do you think you could provide a more complete example? I am unable to replicate.

from openpyxl.workbook import Workbook
from typing_extensions import reveal_type


def foo(unknown_values_only: bool) -> None:
    reveal_type(Workbook()["sheet"].iter_rows())
    reveal_type(next(Workbook()["sheet"].iter_rows()))
    reveal_type(Workbook()["sheet"].iter_rows(values_only=True))
    reveal_type(next(Workbook()["sheet"].iter_rows(values_only=True)))
    reveal_type(Workbook()["sheet"].iter_rows(values_only=unknown_values_only))
    reveal_type(next(Workbook()["sheet"].iter_rows(values_only=unknown_values_only)))

mypy --strict C:\Users\Avasam\Desktop\openpyxl_type_test.py

PS C:\Users\Avasam> mypy --strict C:\Users\Avasam\Desktop\openpyxl_type_test.py
Desktop\openpyxl_type_test.py:6: note: Revealed type is "typing.Generator[builtins.tuple[Union[openpyxl.cell.cell.Cell, openpyxl.cell.cell.MergedCell], ...], None, None]"
Desktop\openpyxl_type_test.py:7: note: Revealed type is "builtins.tuple[Union[openpyxl.cell.cell.Cell, openpyxl.cell.cell.MergedCell], ...]"
Desktop\openpyxl_type_test.py:8: note: Revealed type is "typing.Generator[builtins.tuple[Union[builtins.str, builtins.float, datetime.datetime, None], ...], None, None]"
Desktop\openpyxl_type_test.py:9: note: Revealed type is "builtins.tuple[Union[builtins.str, builtins.float, datetime.datetime, None], ...]"
Desktop\openpyxl_type_test.py:10: note: Revealed type is "Union[typing.Generator[builtins.tuple[Union[openpyxl.cell.cell.Cell, openpyxl.cell.cell.MergedCell], ...], None, None], typing.Generator[builtins.tuple[Union[builtins.str, builtins.float, datetime.datetime, None], ...], None, None]]"
Desktop\openpyxl_type_test.py:11: note: Revealed type is "builtins.tuple[Union[builtins.str, builtins.float, datetime.datetime, None, openpyxl.cell.cell.Cell, openpyxl.cell.cell.MergedCell], ...]"
Success: no issues found in 1 source file

pyright C:\Users\Avasam\Desktop\openpyxl_type_test.py

c:\Users\Avasam\Desktop\openpyxl_type_test.py
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:6:17 - information: Type of "Workbook()["sheet"].iter_rows()" is "Generator[tuple[Cell | MergedCell, ...], None, None]"
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:7:17 - information: Type of "next(Workbook()["sheet"].iter_rows())" is "tuple[Cell | MergedCell, ...]"
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:8:17 - information: Type of "Workbook()["sheet"].iter_rows(values_only=True)" is "Generator[tuple[str | float | datetime | None, ...], None, None]"
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:9:17 - information: Type of "next(Workbook()["sheet"].iter_rows(values_only=True))" is "tuple[str | float | datetime | None, ...]"
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:10:17 - information: Type of "Workbook()["sheet"].iter_rows(values_only=unknown_values_only)" is "Generator[tuple[Cell | MergedCell, ...], None, None] | Generator[tuple[str | float | datetime | None, ...], None, None]"
  c:\Users\Avasam\Desktop\openpyxl_type_test.py:11:17 - information: Type of "next(Workbook()["sheet"].iter_rows(values_only=unknown_values_only))" is "tuple[Cell | MergedCell, ...] | tuple[str | float | datetime | None, ...]"
0 errors, 0 warnings, 6 informations

I do not understand why a Generator is not considered as SupportsNext

The error seem to imply that the generic type of the expected SupportsNext is what's mismatched (notice how in your logs, there's no MergedCell as part of the expected type).

My guess would be that you are assigning to a predefined value that doesn't match the inferred return type of next. But it's hard to say without a complete reproducer.

[mutricyl]

(notice how in your logs, there's no MergedCell as part of the expected type)

I got the point ! I spent some time replicating the issue and there is a replicable example:

import datetime
from typing import TypeAlias, Union

import openpyxl
from openpyxl.workbook import Workbook
from typing_extensions import reveal_type

wb = Workbook()

openpyxl_value_types: TypeAlias = Union[str, float, datetime.datetime, None,
                                        int]
openpyxl_types: TypeAlias = Union[openpyxl_value_types,
                                  openpyxl.cell.cell.Cell]


def test(value: bool, sheet: str) -> tuple[openpyxl_types, ...]:
    wb = Workbook()
    reveal_type(next(wb[sheet].iter_rows(values_only=value)))
    return next(wb[sheet].iter_rows(values_only=value))

So I bascially miss the MergedCell in my return type...

Thanks for the help @Avasam , I'll close the issue.