Handle nil attributes when loading generation config

Author: jonatanklosko

lib/bumblebee/text/generation_config.ex

@@ -287,10 +287,10 @@ defmodule Bumblebee.Text.GenerationConfig do
 
       opts =
         convert!(data,
-          max_new_tokens: {"max_new_tokens", number()},
-          min_new_tokens: {"min_new_tokens", number()},
-          max_length: {"max_length", number()},
-          min_length: {"min_length", number()},
+          max_new_tokens: {"max_new_tokens", optional(number())},
+          min_new_tokens: {"min_new_tokens", optional(number())},
+          max_length: {"max_length", optional(number())},
+          min_length: {"min_length", optional(number())},
           decoder_start_token_id: {"decoder_start_token_id", optional(number())},
           bos_token_id: {"bos_token_id", optional(number())},
           eos_token_id: {"eos_token_id", optional(number())},
@@ -306,10 +306,11 @@ defmodule Bumblebee.Text.GenerationConfig do
         data
         |> convert!(
           sample: {"do_sample", boolean()},
-          top_k: {"top_k", number()},
-          top_p: {"top_p", number()},
-          alpha: {"penalty_alpha", number()}
+          top_k: {"top_k", optional(number())},
+          top_p: {"top_p", optional(number())},
+          alpha: {"penalty_alpha", optional(number())}
         )
+        |> Enum.reject(fn {_key, value} -> value == nil end)
         |> Map.new()
         |> case do
           %{sample: true} = opts ->