Projection does not affect SQL [DATAREST-1171]

Sam Kruglov opened DATAREST-1171 and commented

I define a User with firstName and SecondName and a projection FirstNameOnly.
I create a UserRepository and inside that define a query method ```
FirstNameOnly findFirstNameById(@Param("id") Long id);

Now, there are two ways I can access it:
1. localhost:8080/users/1?projection=FirstNameOnly
1. localhost:8080/users/search/findFirstNameById?id=1

First approach produces valid JSON, but SQL query actually selects all of the fields anyway.
The second approach produces valid JSON and valid SQL query (only selects the "firstName" column).

I would really prefer the first approach to also generate valid SQL. What do you think?

Affects: 2.6.9 (Ingalls SR9)