Error when decoding empty lists from maps
alejgh opened this issue · 2 comments
alejgh commented
Hi, thanks for your work on this library. I have been using Nestru for a while to decode maps from JSON data into Elixir structs. In the last version of Nestru (0.3.2) the library is returning an error when decoding a map that has an empty list.
Environment
- Elixir version (elixir -v): 1.14.3
- Nestru version (mix deps | grep nestru | head -1): 0.3.2
Actual behavior
Supposing we have defined the following structs:
defmodule Order do
@derive {Nestru.Decoder, hint: %{items: [LineItem]}}
defstruct [:id, :items]
end
defmodule LineItem do
@derive Nestru.Decoder
defstruct [:amount]
endIf we provide a list with LineItem values for the items field, everything works as expected:
map = %{
"id" => "A548",
"items" => [%{"amount" => 150}, %{"amount" => 350}]
}
{:ok, model} = Nestru.decode_from_map(map, Order){:ok, %Order{id: "A548", items: [%LineItem{amount: 150}, %LineItem{amount: 350}]}}However, if we provide an empty list for the items field, an error is raised:
map = %{
"id" => "A548",
"items" => [],
}
{:ok, model} = Nestru.decode_from_map(map, Order){:error, %{ get_in_keys: [#Function<8.75249601/3 in Access.key!/1>], message: %{message: "The first argument should be a list. Got [] instead."}, path: ["items"]}}Expected behavior
The map should be decoded correctly, creating an Order struct with an empty list in the items field:
{:ok, %Order{id: "A548", items: []}}Additional notes
This new error when providing empty lists appeared in version 0.3.2 of Nestru. In version 0.3.1, the expected behavior shown above occurs instead.
IvanRublev commented