Some comparisons between different classes of string (e.g.string[pyarrow] andstr) raise. Resolving this is straightforward except for what class should be returned. I would expect it should always be the left obj, e.g.string[pyarrow] == str should returnstring[pyarrow] whereasstr == string[pyarrow] should returnstr. Is this the concensus?

We currently run into issues with how Python handles subclasses with comparison dunders.

lhs=pd.array(["x",pd.NA,"y"],dtype="string[pyarrow]")rhs=pd.array(["x",pd.NA,"y"],dtype=pd.StringDtype("pyarrow",np.nan))print(lhs.__eq__(rhs))# <ArrowExtensionArray># [True, <NA>, True]# Length: 3, dtype: bool[pyarrow]print(lhs==rhs)# [ True False  True]

The two results above differ becauseArrowStringArrayNumpySemantics is a proper subclass ofArrowStringArray and therefore Python first callsrhs.__eq__(lhs).

We can avoid this by special casing this particular case inArrowStringArrayNumpySemantics, but I wanted to open up an issue for discussion before proceeding.

cc@WillAyd@jorisvandenbossche