Bug: Decoder error message creation

[Massolari]

When trying to decode a nullable field using the wrong code below:

  use link_flair_text <- decode.optional_field(
    "link_flair_text",
    "",
    decode.string,
  )

The error I get is: UnableToDecode([DecodeError("String", "Atom", ["data", "children", "0", "data"])]). The field link_flair_text is, indeed on data.children[0].data, but the message doesn't say the error is on the field link_flair_text

[lpil]

Oh dear! Thank you!

Could you please share your code and data please so we can replicate and fix the problem.

[Massolari]

I managed to reproduce it in the Gleam playground. You see that the error message doesn't say that the error is on the field "a"

[lpil]

Thank you.

import gleam/io
import gleam/dict
import gleam/dynamic
import gleam/dynamic/decode

pub fn main() {
  let data = dict.from_list([
    #("a", Nil)
  ])
  
  let decoder = {
    use bar <- decode.optional_field("a", "", decode.string)
    
    decode.success(bar)
  }
  
  data
  |> dynamic.from
  |> decode.run(decoder)
  |> io.debug
}