[rasterio] Allow WarpedVRT to take DatasetWriter

[jack-volantautonomy]

The aim of this PR is to change the typing so that the src dataset provided to WarpedVRT can take a rasterio.io.DatasetWriter too. This is because a DatasetWriter also has the read methods required on it so is a suitable parameter type.

Not sure if this is the most correct fix and if we should make use of protocols instead but should do the job and might just be the fix we need.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[srittau]

I'm not familiar with rasterio, but I see in the source that both DatasetWriter and DatasetReader derive from DatasetReaderBase. Would it maybe make sense to use that as type annotation?

Cc @thomas-maschler as original author.

[thomas-maschler]

I will have to check if a WarpedVRT also takes a WarpedVRT as input. If yes, DatasetReaderBase seems more appropriate. I am currently traveling and won't be able to look at this for another week.

[jack-volantautonomy]

@thomas-maschler you okay to take a look into this now?

[thomas-maschler]

@jack-volantautonomy, thanks for the reminder.

Two things: The signature should use DatasetReaderBase, not DatasetReader | DatasetWriter.

However, DatasetWriter is deprecated and will issue a warning and will stop in future versions. Rasterio wants a readonly source. It will be best to overload the init method and add the deprecation note already here.

class WarpedVRTReaderBase(DatasetReaderBase):
    src_dataset: DatasetReaderBase
    src_crs: CRS
    src_transform: Affine | None
    resampling: Resampling
    tolerance: float
    src_nodata: float | None
    dst_nodata: float | None
    working_dtype: DTypeLike | None
    warp_extras: dict[str, _GDALOption]

    @overload
    @deprecated(
        "Source datasets opened in modes other than 'r' emit a "
        "RasterioDeprecationWarning and will be disallowed in a future rasterio "
        "release; reopen the dataset read-only before wrapping it."
    )
    def __init__(
        self,
        src_dataset: DatasetWriterBase,
        src_crs: CRSInput | None = None,
        crs: CRSInput | None = None,
        resampling: Resampling = ...,
        tolerance: float = 0.125,
        src_nodata: float | None = ...,
        nodata: float | None = ...,
        width: int | None = None,
        height: int | None = None,
        src_transform: Affine | None = None,
        transform: Affine | None = None,
        init_dest_nodata: bool = True,
        src_alpha: int = 0,
        dst_alpha: int = 0,
        add_alpha: bool = False,
        warp_mem_limit: int = 0,
        dtype: DTypeLike | None = None,
        **warp_extras: _GDALOption,
    ) -> None: ...
    @overload
    def __init__(
        self,
        src_dataset: DatasetReaderBase,
        src_crs: CRSInput | None = None,
        crs: CRSInput | None = None,
        resampling: Resampling = ...,
        tolerance: float = 0.125,
        src_nodata: float | None = ...,
        nodata: float | None = ...,
        width: int | None = None,
        height: int | None = None,
        src_transform: Affine | None = None,
        transform: Affine | None = None,
        init_dest_nodata: bool = True,
        src_alpha: int = 0,
        dst_alpha: int = 0,
        add_alpha: bool = False,
        warp_mem_limit: int = 0,
        dtype: DTypeLike | None = None,
        **warp_extras: _GDALOption,
    ) -> None: ...
    ```