Are properties always fetched?

[nk-coding]

Hi,
the documentation for fetching data says, that fields backed by a property are always fetched, regardless whether or not asked for:

If we expose the reviews field as a property it will always be populated regardless whether or not your client actually asks for it.

However, when I added a breakpoint to a property getter, the program only ran in the breakpoint, if the query asked for that field.
Therefore I want to ask if

1. I can rely on that behavior (will the property getter only be called if it is queried for)
2. This is a bug/outdated information in the documentation (if so, it might be related to Call hooks for return type on properties #1112, as this PR changed how properties are fetched, however I am really not sure there)

[dariuszkuc]

Hello 👋
Yes data fetchers for corresponding fields (regardless whether they are backed by a function or a property) will only be called if given query explicitly asks for it.

Documentation simply states that field has to be somehow initialized, i.e. given schema

type Foo {
  # this field is quickly resolved in milliseconds
  bar: String!
  # this field is backed by slow API and it takes 10 second to compute
  baz: Int! 
}

If you simply expose that type as a

data class Foo(val bar: String, val baz: Int)

then it is not possible to create an instance of class Foo without calculating the value of bar (fast) and baz (slow) fields. Regardless whether user asks for slow baz or not, we HAVE to calculate it before returning Foo from a function. On the other hand, if you expose baz as a function then that function will only be invoked if user explicitly asks for it.

class Foo(val bar: String) {
  fun baz(): Int {
     // some 
     // this code only executes if query asks for baz
  }
}

[nk-coding]

Thanks for the answer