chore: Use enum to represent CAST eval_mode in expr.proto

[andygrove]

What is the problem the feature request solves?

When I added eval_mode to the Cast message in expr.proto I defined it as a string but it should really be an enum.

enum EvalMode {
  LEGACY = 0;
  TRY = 1;
  ANSI = 2;
}

Describe the potential solution

No response

Additional context

No response

[prashantksharma]

@andygrove

Thank you for the issue description.

I would like to work on this issue. If no one else is working on it.
Can I take it up ?

[viirya]

Definitely yes. Thanks @prashantksharma

[parthchandra]

I suppose for this issue it is okay to violate the rule to not modify a field in a protobuf message because we haven't published anything yet.

[andygrove]

I suppose for this issue it is okay to violate the rule to not modify a field in a protobuf message because we haven't published anything yet.

Yes, absolutely.

[prashantksharma]

@andygrove , cc: @viirya

Minor Query before opening PR

Summary:

• Have made changes to expr.proto and QueryPlanSerde.scala. The changes have been pushed to a separate branch on my fork. The comparison can be seen here:
• make test-rust gives following error.

Minor Query:
Before opening the PR, I would like to confirm: if I should go ahead and resolve the error for planner.rs or a separate issue needs to be created for this ?

[andygrove]

On the Rust side you will need a match statement to convert the protobuf i32 to the Rust enum (0 -> legacy, 1 -> try, 2 -> ansi). Perhaps take a look at how we handle one of the other enums defined in the proto and follow the same pattern?

[andygrove]

@prashantksharma also, feel free to create a draft PR as it can be easier for maintainers to make suggestions on the PR

[prashantksharma]

@andygrove

Thank you so much for your feedback:

On the Rust side you will need a match statement to convert the protobuf i32 to the Rust enum (0 -> legacy, 1 -> try, 2 -> ansi). Perhaps take a look at how we handle one of the other enums defined in the proto and follow the same pattern?

I will make necessary changes based on my understanding of the above comment by you.

And, Thank you for your suggesting creation of draft PR, after making necessary updates, I will do that.

[prashantksharma]

@andygrove cc: @viirya

I have opended a draft PR.

I have tested the changes using

• make test-rust
• make test-jvm

Details on PR message:#415