Hello, Igniters.
Currently, binary marshaller works as follows(Say, we have a class `User` then):
IgniteBinary#toBinary(User)` -> BinaryObject
IgniteBinary#toBinary(User[])` -> Object[]
IgniteBinary#toBinary(Object[])` -> Object[]
This means, that we lose array component type information during binary
serialization.
AFAIK, it’s a design choice made during binary infrastructure development.
This lead to the following disadvantages:
1. `IgniteBinary` can’t be used as a universal SerDe mechanism.
2. Ignite internals(service grid, .Net calls) contains many tweaks and hacks to
deal with custom user array and still has many issues [1]
I propose to make breaking changes and fix the custom user array SeDe as
follows:
1. Implement binary serialization that correctly Ser and Deser array
using some kind of the wrapper (BinaryArrayWrapper).
IgniteBinary#toBinary(User)` -> BinaryObject
IgniteBinary#toBinary(User[])` -> BinaryObject
IgniteBinary#toBinary(Object[])` -> BinaryObject
2. Introduce system flag `IGNITE_USE_BINARY_ARRAY` that enables correct
SerDe of arrays. The default value is false to keep backward compatibility in
the next Ignite release(2.11).
3. Set `IGNITE_USE_BINARY_ARRAY` to `true` in the ongoing Ignite
releases (2.12).
WDYT?
[1] https://issues.apache.org/jira/browse/IGNITE-14299
