`DictEncoder::reset` does not clear the encoder state

[mnshdw]

What happened?

reset is documented as "Clear the encoder state to make it ready for a new round of decoding", but the implementations do not clear it properly.

• BytesDictBuilder::reset keeps lookup and null_code
• PrimitiveDictBuilder::reset keeps lookup, null_code and values

Steps to reproduce

BytesDictBuilder:

let session = vortex_array::array_session();
let mut ctx = session.create_execution_ctx();

let first = VarBinViewArray::from_iter_str(["one", "two"]).into_array();
let mut encoder = dict_encoder(&first, &UNCONSTRAINED);
encoder.encode(&first, &mut ctx).unwrap();

encoder.reset();

let second = VarBinViewArray::from_iter_str(["one", "three"]).into_array();
encoder.encode(&second, &mut ctx).unwrap(); // index out of bounds: the len is 0 but the index is 0

PrimitiveDictBuilder

let session = vortex_array::array_session();
let mut ctx = session.create_execution_ctx();

let first = PrimitiveArray::from_option_iter([Some(1i32), None, Some(3)]).into_array();
let mut encoder = dict_encoder(&first, &UNCONSTRAINED);
encoder.encode(&first, &mut ctx).unwrap();

encoder.reset();

let second = PrimitiveArray::from_option_iter([Some(4i32), Some(5)]).into_array();
let codes = encoder.encode(&second, &mut ctx).unwrap();
assert_eq!(codes.as_slice::<u32>(), &[0, 1]); // assertion `left == right` failed
                                              //   left: [3, 4]
                                              //  right: [0, 1]

Environment

• Vortex develop
• Rust 1.98.0

Additional context

No response