feat: add workarounds for duckdb MAP bugs

[NickCrews]

Is your feature request related to a problem?

see
duckdb/duckdb#11115
and
duckdb/duckdb#11116

This might be out of scope, and we should just wait for duckdb to fix these upstream, but we could add some workarounds for these bugs in ibis. I am running into these and am having to implement my own little wrappers, eg

def _map_values(m: ir.MapValue) -> ir.ArrayValue:
    """workaround for https://github.com/duckdb/duckdb/issues/11116"""
    normal = m.values()
    null = ibis.literal(None, type=dt.Array(value_type=m.type().value_type))
    return m.isnull().ifelse(null, normal)

feel free to close this out if you don't want to take this on (I don't blame you if you don't 😉 )

Describe the solution you'd like

I'm not sure where in the stack these fixes would need to go, at compile time, or just when creating expressions.

What version of ibis are you running?

main

What backend(s) are you using, if any?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[cpcloud]

Thanks! Looks like you've gone down a map 🐰 🕳️

I think it's reasonable to add these workarounds for now.

[NickCrews]

yeah seriously talk about a 🐰 🕳️ . I was convinced for hours it was bugs in my code wheeeeee

here is what I currently use. I have unit tests for functions that use these, but I don't have unit tests for these as individuals.

def map_keys(m: ir.MapValue) -> ir.ArrayValue:
    """workaround for https://github.com/duckdb/duckdb/issues/11116"""
    normal = m.keys()
    null = ibis.literal(None, type=dt.Array(value_type=m.type().key_type))
    return m.isnull().ifelse(null, normal)


def map_values(m: ir.MapValue) -> ir.ArrayValue:
    """workaround for https://github.com/duckdb/duckdb/issues/11116"""
    normal = m.values()
    null = ibis.literal(None, type=dt.Array(value_type=m.type().value_type))
    return m.isnull().ifelse(null, normal)


def map_(keys: ir.ArrayValue, values: ir.ArrayValue) -> ir.MapValue:
    """workaround for https://github.com/duckdb/duckdb/issues/11115"""
    either_null = keys.isnull() | values.isnull()
    regular = ibis.map(keys, values)
    null = ibis.literal(
        None,
        type=dt.Map(
            key_type=keys.type().value_type, value_type=values.type().value_type
        ),
    )
    return either_null.ifelse(null, regular)

[gforsyth]

Yeah, this would be good to get in for 9.0.

@NickCrews do you have the bandwidth to PR this in? We probably do want unit tests for them, and probably also some xfailed tests that will start to XPASS when the upstream issues are fixed.

[NickCrews]

In that PR I addressed duckdb/duckdb#11115, which

• is more common
• leads to incorrect results in the NULL NULL case (!)

Once that is in then I can tackle duckdb/duckdb#11116, which I think

• is much more rare
• usually leads to errors instead of incorrect reuslts.

[cpcloud]

I'll work on getting the rest of the map family of functions behaving consistently here.