BUG: SparseFrameAccessor.to_dense ignores _constructor

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Reproducible Example

import scipy.sparse as sp
import pandas as pd

class MF(pd.DataFrame):
    @property
    def _constructor(self):
        return MF

arr = pd.core.arrays.SparseArray.from_spmatrix(sp.csr_matrix((3, 1)))
df = MF(arr)
print(type(df.sparse.to_dense()).__name__)

Issue Description

to_dense ignores _constructor and always returns DataFrame.

    def to_dense(self) -> DataFrame:
        from pandas import DataFrame

        data = {k: v.array.to_dense() for k, v in self._parent.items()}
        return DataFrame(data, index=self._parent.index, columns=self._parent.columns)

I think the code should look like this:

    def to_dense(self) -> DataFrame:
        data = {k: v.array.to_dense() for k, v in self._parent.items()}
        constr = self._parent._constructor
        return constr(data, index=self._parent.index, columns=self._parent.columns)

We use(d) an ugly workaround, but it will stop working in Pandas 3 because of #58733. See our temporary solution in https://github.com/biolab/orange3/pull/6897/commits/98c48e1b3b7c705f10af195a395213114dc2a917. :(

Expected Behavior

When subclassing DataFrame (which, I know, is discouraged, but sometimes difficult to avoid), to_dense should observe the constructor returned by _constructor.

Installed Versions

INSTALLED VERSIONS ------------------ commit : 23c497bb2f7e05af1fda966e7fb04db942453559 python : 3.11.10 python-bits : 64 OS : Darwin OS-release : 23.6.0 Version : Darwin Kernel Version 23.6.0: Mon Jul 29 21:14:30 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T6000 machine : arm64 processor : arm byteorder : little LC_ALL : None LANG : en_GB.UTF-8 LOCALE : en_GB.UTF-8 pandas : 3.0.0.dev0+1524.g23c497bb2f numpy : 1.26.4 dateutil : 2.9.0.post0 pip : 24.2 Cython : 3.0.11 sphinx : 4.5.0 IPython : 8.27.0 adbc-driver-postgresql: None adbc-driver-sqlite : None bs4 : 4.13.0b2 blosc : None bottleneck : 1.4.0 fastparquet : None fsspec : None html5lib : 1.1 hypothesis : None gcsfs : None jinja2 : 3.1.4 lxml.etree : 5.3.0 matplotlib : 3.9.2 numba : None numexpr : None odfpy : None openpyxl : 3.1.5 psycopg2 : None pymysql : None pyarrow : None pyreadstat : None pytest : 8.3.3 python-calamine : None pytz : 2024.2 pyxlsb : None s3fs : None scipy : 1.15.0.dev0+git20240926.4c936c8 sqlalchemy : None tables : None tabulate : None xarray : None xlrd : 2.0.1 xlsxwriter : 3.2.0 zstandard : None tzdata : 2024.1 qtpy : 2.4.1 pyqt5 : None

pandas-dev / pandas