Ensure an object has unique fields

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 
 ## Unreleased
-
+- Bug Fix: [Validate field identifier uniqueness](https://github.com/absinthe-graphql/absinthe/pull/1200)
 - Bug Fix: [Validate type references for invalid wrapped types](https://github.com/absinthe-graphql/absinthe/pull/1195)
 - Breaking Bugfix: [Validate repeatable directives on schemas](https://github.com/absinthe-graphql/absinthe/pull/1179)
 - Bug Fix: Adds **optional fix** for non compliant built-in scalar Int type. `use Absinthe.Schema, use_spec_compliant_int_scalar: true` in your schema to use the fixed Int type. It is also advisable to upgrade for custom types if you are leveraging the use of integers outside the GraphQl standard. [#1131](https://github.com/absinthe-graphql/absinthe/pull/1131).

lib/absinthe/phase/schema/validation/unique_field_names.ex

@@ -8,6 +8,7 @@ defmodule Absinthe.Phase.Schema.Validation.UniqueFieldNames do
     bp =
       bp
       |> Blueprint.prewalk(&handle_schemas(&1, :name))
+      |> Blueprint.prewalk(&handle_schemas(&1, :identifier))
 
     {:ok, bp}
   end
@@ -32,7 +33,7 @@ defmodule Absinthe.Phase.Schema.Validation.UniqueFieldNames do
         name_counts = Enum.frequencies_by(object.fields, &Map.get(&1, key))
 
         if duplicate?(name_counts, field, key) do
-          Absinthe.Phase.put_error(field, error(field, object))
+          Absinthe.Phase.put_error(field, error(field, object, key))
         else
           field
         end
@@ -50,20 +51,28 @@ defmodule Absinthe.Phase.Schema.Validation.UniqueFieldNames do
     Map.get(name_counts, field_identifier, 0) > 1
   end
 
-  defp error(field, object) do
+  defp error(field, object, key) do
     %Absinthe.Phase.Error{
-      message: explanation(field, object),
+      message: explanation(field, object, key),
       locations: [field.__reference__.location],
       phase: __MODULE__,
       extra: field
     }
   end
 
-  def explanation(field, object) do
+  def explanation(field, object, :name) do
     """
     The field #{inspect(field.name)} is not unique in type #{inspect(object.name)}.
 
     The field must have a unique name within that Object type; no two fields may share the same name.
     """
   end
+
+  def explanation(field, object, :identifier) do
+    """
+    The field identifier #{inspect(field.identifier)} is not unique in type #{inspect(object.name)}.
+
+    The field must have a unique identifier within that Object type; no two fields may share the same identifier.
+    """
+  end
 end

test/absinthe/schema/rule/unique_field_names_test.exs

@@ -1,7 +1,21 @@
 defmodule Absinthe.Schema.Rule.UniqueFieldNamesTest do
   use Absinthe.Case, async: true
 
-  @duplicate_object_fields ~S(
+  @duplicate_object_fields_macro ~S(
+    defmodule DuplicateObjectFields do
+      use Absinthe.Schema
+
+      query do
+      end
+
+      object :dog do
+        field :name, :string
+        field :name, :integer, name: "dogName"
+      end
+    end
+    )
+
+  @duplicate_object_fields_sdl ~S(
   defmodule DuplicateObjectFields do
     use Absinthe.Schema
 
@@ -49,11 +63,19 @@ defmodule Absinthe.Schema.Rule.UniqueFieldNamesTest do
   end
   )
 
+  test "errors on non unique object field identifier" do
+    error = ~r/The field identifier :name is not unique in type \"Dog\"./
+
+    assert_raise(Absinthe.Schema.Error, error, fn ->
+      Code.eval_string(@duplicate_object_fields_macro)
+    end)
+  end
+
   test "errors on non unique object field names" do
     error = ~r/The field \"name\" is not unique in type \"Dog\"./
 
     assert_raise(Absinthe.Schema.Error, error, fn ->
-      Code.eval_string(@duplicate_object_fields)
+      Code.eval_string(@duplicate_object_fields_sdl)
     end)
   end