improvement: add tests & improve behavior of update managed relationships

lib/resource/resource.ex

@@ -1724,7 +1724,7 @@ defmodule AshGraphql.Resource do
 
     if could_lookup? || could_match? do
       pkey_fields =
-        if managed_relationship.lookup_with_primary_key? do
+        if managed_relationship.lookup_with_primary_key? || could_match? do
           resource
           |> pkey_fields(schema, false)
           |> Enum.map(fn field ->
@@ -1736,6 +1736,13 @@ defmodule AshGraphql.Resource do
 
       resource
       |> Ash.Resource.Info.identities()
+      |> then(fn identities ->
+        if could_lookup? do
+          identities
+        else
+          []
+        end
+      end)
       |> Enum.filter(fn identity ->
         is_nil(managed_relationship.lookup_identities) ||
           identity.name in managed_relationship.lookup_identities

test/support/resources/post.ex

@@ -85,6 +85,7 @@ defmodule AshGraphql.Test.Post do
 
     managed_relationships do
       managed_relationship :with_comments, :comments
+      managed_relationship :update_with_comments, :comments, lookup_with_primary_key?: true
 
       managed_relationship :with_comments_and_tags, :comments,
         lookup_with_primary_key?: true,
@@ -106,6 +107,7 @@ defmodule AshGraphql.Test.Post do
       create :create_post_with_comments_and_tags, :with_comments_and_tags
 
       update :update_post, :update
+      update :update_post_with_comments, :update_with_comments
       update :update_post_confirm, :update_confirm
       update :update_best_post, :update, read_action: :best_post, identity: false
 
@@ -204,6 +206,12 @@ defmodule AshGraphql.Test.Post do
 
     update :update, primary?: true
 
+    update :update_with_comments do
+      argument(:comments, {:array, :map})
+
+      change(manage_relationship(:comments, type: :direct_control))
+    end
+
     update :update_confirm do
       argument(:confirmation, :string)
       validate(confirm(:text, :confirmation))

test/update_test.exs

@@ -43,6 +43,98 @@ defmodule AshGraphql.UpdateTest do
              resp
   end
 
+  test "an update with a managed relationship works" do
+    resp =
+      """
+      mutation CreatePostWithComments($input: CreatePostWithCommentsInput) {
+        createPostWithComments(input: $input) {
+          result{
+            id
+            text
+            comments(sort:{field:TEXT}){
+              id
+              text
+            }
+          }
+          errors{
+            message
+          }
+        }
+      }
+      """
+      |> Absinthe.run(AshGraphql.Test.Schema,
+        variables: %{
+          "input" => %{
+            "text" => "foobar",
+            "comments" => [
+              %{"text" => "foobar"},
+              %{"text" => "barfoo"}
+            ]
+          }
+        }
+      )
+
+    assert {:ok, result} = resp
+
+    refute Map.has_key?(result, :errors)
+
+    assert %{
+             data: %{
+               "createPostWithComments" => %{
+                 "result" => %{
+                   "id" => post_id,
+                   "text" => "foobar",
+                   "comments" => [
+                     %{"id" => comment_id, "text" => "barfoo"},
+                     %{"text" => "foobar"}
+                   ]
+                 }
+               }
+             }
+           } = result
+
+    resp =
+      """
+      mutation UpdatePostWithComments($id: ID!, $input: UpdatePostWithCommentsInput) {
+        updatePostWithComments(id: $id, input: $input) {
+          result{
+            comments(sort:{field:TEXT}){
+              id
+              text
+            }
+          }
+          errors{
+            message
+          }
+        }
+      }
+      """
+      |> Absinthe.run(AshGraphql.Test.Schema,
+        variables: %{
+          "id" => post_id,
+          "input" => %{
+            "comments" => [
+              %{"text" => "barfoonew", "id" => comment_id}
+            ]
+          }
+        }
+      )
+
+    assert {:ok, result} = resp
+
+    refute Map.has_key?(result, :errors)
+
+    assert %{
+             data: %{
+               "updatePostWithComments" => %{
+                 "result" => %{
+                   "comments" => [%{"id" => ^comment_id, "text" => "barfoonew"}]
+                 }
+               }
+             }
+           } = result
+  end
+
   test "an update with a configured read action and no identity works" do
     post =
       AshGraphql.Test.Api.create!(