Improve typechecks on nested args

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## Unreleased
+- POTENTIALLY BREAKING Bug Fix: [Validate variable usage in nested input arguments](https://github.com/absinthe-graphql/absinthe/pull/1290).This could break incoming documents previously considered valid. Skip the Absinthe.Phase.Document.Arguments.VariableTypesMatch phase to avoid this check. See Absinthe.Pipeline on adjusting the document pipeline.
+
 ## 1.7.6
 
 - Bugfix: [Handle non_null(list_of(:thing)) with null list elements properly](https://github.com/absinthe-graphql/absinthe/pull/1259)

lib/absinthe/phase/document/arguments/variable_types_match.ex

@@ -59,6 +59,18 @@ defmodule Absinthe.Phase.Document.Arguments.VariableTypesMatch do
     {:halt, node}
   end
 
+  defp check_variable_type(
+         %Absinthe.Blueprint.Input.Field{
+           input_value: %Blueprint.Input.Value{
+             raw: %{content: %Blueprint.Input.Variable{} = variable}
+           }
+         } = node,
+         operation_name,
+         variable_defs
+       ) do
+    compare_variable_with_definition(variable, node, operation_name, variable_defs)
+  end
+
   defp check_variable_type(
          %Absinthe.Blueprint.Input.Argument{
            input_value: %Blueprint.Input.Value{
@@ -68,6 +80,14 @@ defmodule Absinthe.Phase.Document.Arguments.VariableTypesMatch do
          operation_name,
          variable_defs
        ) do
+    compare_variable_with_definition(variable, node, operation_name, variable_defs)
+  end
+
+  defp check_variable_type(node, _, _) do
+    node
+  end
+
+  defp compare_variable_with_definition(variable, node, operation_name, variable_defs) do
     location_type = node.input_value.schema_node
     location_definition = node.schema_node
 
@@ -95,10 +115,6 @@ defmodule Absinthe.Phase.Document.Arguments.VariableTypesMatch do
     end
   end
 
-  defp check_variable_type(node, _, _) do
-    node
-  end
-
   def types_compatible?(type, type, _, _) do
     true
   end

test/absinthe/execution/arguments/input_object_test.exs

@@ -32,7 +32,7 @@ defmodule Absinthe.Execution.Arguments.InputObjectTest do
   end
 
   @graphql """
-  query ($email: String) {
+  query ($email: String!) {
     contacts(contacts: [{email: $email}, {email: $email}])
   }
   """
@@ -67,7 +67,7 @@ defmodule Absinthe.Execution.Arguments.InputObjectTest do
   end
 
   @graphql """
-  query ($email: String, $defaultWithString: String) {
+  query ($email: String!, $defaultWithString: String) {
     user(contact: {email: $email, defaultWithString: $defaultWithString})
   }
   """

test/absinthe/integration/execution/input_object_test.exs

@@ -43,4 +43,29 @@ defmodule Elixir.Absinthe.Integration.Execution.InputObjectTest do
                variables: %{"input" => true}
              )
   end
+
+  @query """
+  mutation ($input: String) {
+    updateThing(id: "foo", thing: {value: $input}) {
+      name
+      value
+    }
+  }
+  """
+
+  test "errors if an invalid type is passed to nested arg" do
+    assert {:ok,
+            %{
+              errors: [
+                %{
+                  locations: [%{column: 41, line: 2}],
+                  message:
+                    "Variable `$input` of type `String` found as input to argument of type `Int`."
+                }
+              ]
+            }} ==
+             Absinthe.run(@query, Absinthe.Fixtures.Things.MacroSchema,
+               variables: %{"input" => 1}
+             )
+  end
 end