Files written with Julia's Arrow.jl in IPC format cannot be read by arrow-rs

[pcjentsch]

Describe the bug
Files written with Julia's Arrow.jl IPC format have a footer that causes arrow-rs to panic. I think this is a bug on the side of arrow-rs because arrow2 can read them.

To Reproduce
Reproduced in this small repository.

git clone https://github.com/pcjentsch/testing_ipc_issue.git
cd testing_ipc_issue/test_ipc
cargo run

output

Ok((Schema { fields: [Field { name: "a", data_type: Int64, is_nullable: false, metadata: {} }], metadata: {} }, [Chunk { arrays: [Int64[1, 2, 3]] }]))
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /home/workaccount/.cargo/registry/src/github.com-1ecc6299db9ec823/arrow-9.0.2/src/ipc/reader.rs:636:44
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Expected behavior
arrow-rs should open the file as arrow2 does.

[alamb]

Looks like there is a function that assumes there is a footer when there may not be -- looks pretty straight forward to me. I'll try and get a fix up in the next few days if no one else beats me to to it.

arrow-rs/arrow/src/ipc/reader.rs

Line 636 in 5737449

for block in footer.dictionaries().unwrap() {

Thank you for the great report @pcjentsch