fix: exception on invalid query arguments

lib/ash/query/query.ex

@@ -726,12 +726,13 @@ defmodule Ash.Query do
     query = to_query(query)
 
     if query.action do
-      with {:arg, argument} when not is_nil(argument) <-
-             {:arg,
-              Enum.find(
-                query.action.arguments,
-                &(&1.name == argument || to_string(&1.name) == argument)
-              )},
+      argument =
+        Enum.find(
+          query.action.arguments,
+          &(&1.name == argument || to_string(&1.name) == argument)
+        )
+
+      with {:arg, argument} when not is_nil(argument) <- {:arg, argument},
            {:ok, casted} <- Ash.Changeset.cast_input(argument.type, value, argument.constraints),
            {:constrained, {:ok, casted}, argument} when not is_nil(casted) <-
              {:constrained,
@@ -742,17 +743,20 @@ defmodule Ash.Query do
         {:arg, nil} ->
           query
 
-        {:constrained, {:ok, nil}, _argument} ->
-          query
+        {:constrained, {:ok, nil}, argument} ->
+          %{query | arguments: Map.put(query.arguments, argument.name, nil)}
 
         {:constrained, {:error, error}, argument} ->
+          query = %{query | arguments: Map.put(query.arguments, argument.name, value)}
           add_invalid_errors(query, argument, error)
 
         {:error, error} ->
+          query = %{query | arguments: Map.put(query.arguments, argument.name, value)}
           add_invalid_errors(query, argument, error)
 
         :error ->
-          nil
+          query = %{query | arguments: Map.put(query.arguments, argument.name, value)}
+          add_invalid_errors(query, argument, "is invalid")
       end
     else
       %{query | arguments: Map.put(query.arguments, argument, value)}
@@ -769,8 +773,11 @@ defmodule Ash.Query do
 
     messages
     |> Enum.reduce(query, fn message, query ->
-      opts = Ash.Changeset.error_to_exception_opts(message, argument)
-      add_error(query, InvalidArgument.exception(opts))
+      message
+      |> Ash.Changeset.error_to_exception_opts(argument)
+      |> Enum.reduce(query, fn opts, query ->
+        add_error(query, InvalidArgument.exception(opts))
+      end)
     end)
   end
 

test/query_test.exs

@@ -0,0 +1,48 @@
+defmodule Ash.Test.QueryTest do
+  @moduledoc false
+  use ExUnit.Case, async: true
+
+  defmodule User do
+    @moduledoc false
+    use Ash.Resource, data_layer: Ash.DataLayer.Ets
+
+    ets do
+      private?(true)
+    end
+
+    actions do
+      read :read do
+        primary? true
+      end
+
+      read :by_id do
+        argument :id, :uuid, allow_nil?: false
+
+        filter expr(id == ^arg(:id))
+      end
+
+      create :create
+      update :update
+    end
+
+    attributes do
+      uuid_primary_key :id
+      attribute :name, :string
+    end
+  end
+
+  defmodule Api do
+    use Ash.Api
+
+    resources do
+      resource User
+    end
+  end
+
+  describe "read argument validation" do
+    test "it returns an appropriate error when an argument is invalid" do
+      query = Ash.Query.for_read(User, :by_id, %{id: "foobar"})
+      assert [%Ash.Error.Query.InvalidArgument{field: :id}] = query.errors
+    end
+  end
+end