[BUG] GetSourceRequest has unnecessary field _source

[zethuman]

What is the bug?

The field _source is not needed, since this parameter has no functionality, since only the option is available - true

How can one reproduce the bug?

Input:

r: opensearchapi.GetSourceRequest{
  Index:      index,
  DocumentID: "2",
  Source:     []string{"false"},
}

Output:
{[{action_request_validation_exception Validation Failed: 1: fetching source can not be disabled; }] action_request_validation_exception Validation Failed: 1: fetching source can not be disabled; }

What is the expected behavior?

Default option is true logically there must be option with false. Expected to does not include the _source field in the response body.

What is your host/environment?

MacOS Ventura / opensearchproject/opensearch:latest / Go 1.15

Possible solution

I can remove this one, since it is not logical to be able to pass a negative value in a request whose purpose is to receive this data.

[wbeckler]

Could fixing this break someone's working code? If so, we might want to put this change into the 3.x line.

[zethuman]

Yes, it may affect the end user code. So, we can already commit into the 3.x line?

[wbeckler]

Is there a way to fix this that preserves working code?

[zethuman]

I think not, since we will remove the source field from the structure, those clients who already have this field in the structure (even if it does not carry functionality) will receive an syntax error. Therefore, it is better to plan for future versions.

[VachaShah]

Can we deprecate this parameter in the next version and then remove in the next major version?

[zethuman]

Yes, why not. If we fix it in this version it will break everything, it's best to plan for the next version

[VachaShah]

@zethuman I was looking at this and looks like the _source field can be used to provide list of fields to be returned. https://github.com/opensearch-project/opensearch-go/blob/main/opensearchapi/api.get_source.go#L239. I tried it in my sample code and it works:

getSourceRequest := opensearchapi.GetSourceRequest{
		Index:      IndexName,
		DocumentID: "1",
		Source:     []string{"title"},
	}

The response was [200 OK] {"title":"Moneyball"}

So the code needs to be fixed rather than _source parameter removed entirely. I will raise a PR soon for this.

[VachaShah]

It is however similar to SourceIncludes then, so we can deprecate one parameter, and moving forward remove in future major versions.