@ianna @henryiii Is this the right fix here? PyExtensionType has been removed in pyarrow 21 and the recommendation in their docs is to use ExtensionType. We deal with ExtensionType right below the lines I changed. The original code is

    if isinstance(storage_type, pyarrow.lib.PyExtensionType):
        raise ValueError(
            "Arrow arrays containing pickled Python objects can't be converted into Awkward Arrays"
        )
    elif isinstance(storage_type, pyarrow.lib.ExtensionType):
        ...
)

My idea was to do the first isinstance check only if pyarrow < 21

@ikrommyd - thanks for looking into it. I think a better way would be to wrap it in a try block.

try:
    # If PyExtensionType exists and matches, raise immediately
    pyext_type = pyarrow.lib.PyExtensionType  # May trigger AttributeError
    if isinstance(storage_type, pyext_type):
        raise ValueError(
            "Arrow arrays containing pickled Python objects can't be converted into Awkward Arrays"
        )
except AttributeError:
    # PyExtensionType doesn't exist (likely newer PyArrow)
    pass

#  Handle remaining ExtensionType cases
if isinstance(storage_type, pyarrow.lib.ExtensionType):
    assert not isinstance(storage_type, AwkwardArrowType)
    # Logic for generic ExtensionType fallback
    return

Ah yeah that's possible since an AttributeError cannot come from somewhere else since we're not running any code in the try block.

@ikrommyd - thanks for making this change. Please see minor changes to the comments.

Done.