improve error for enum type mismatch

Author: nduitz

lib/open_api_spex/cast/enum.ex

@@ -3,8 +3,8 @@ defmodule OpenApiSpex.Cast.Enum do
   alias OpenApiSpex.Cast
 
   def cast(ctx = %Cast{schema: %{enum: enum}, value: value}) do
-    case Enum.find(enum, {:error, :invalid_enum}, &equivalent?(&1, value)) do
-      {:error, :invalid_enum} -> Cast.error(ctx, {:invalid_enum})
+    case Enum.find(enum, {:error, :invalid_enum, enum, value}, &equivalent?(&1, value)) do
+      {:error, :invalid_enum, enum, value} -> Cast.error(ctx, {:invalid_enum, enum, value})
       found -> {:ok, found}
     end
   end

lib/open_api_spex/cast/error.ex

@@ -196,8 +196,8 @@ defmodule OpenApiSpex.Cast.Error do
     |> add_context_fields(ctx)
   end
 
-  def new(ctx, {:invalid_enum}) do
-    %__MODULE__{reason: :invalid_enum}
+  def new(ctx, {:invalid_enum, enum, value}) do
+    %__MODULE__{reason: :invalid_enum, meta: %{enum: enum, value: value}}
     |> add_context_fields(ctx)
   end
 
@@ -329,8 +329,8 @@ defmodule OpenApiSpex.Cast.Error do
     "Invalid format. Expected #{inspect(format)}"
   end
 
-  def message(%{reason: :invalid_enum}) do
-    "Invalid value for enum"
+  def message(%{reason: :invalid_enum, meta: %{enum: enum, value: value}}) do
+    "Invalid value for enum, allowed_values: #{inspect(enum)}, got: #{inspect(value)}"
   end
 
   def message(%{reason: :polymorphic_failed, type: polymorphic_type}) do