From 0d56f4ef45ca6b25fc041d8292fbee085f4061ea Mon Sep 17 00:00:00 2001
From: T Floyd Wright <tfwright@gmail.com>
Date: Thu, 15 Oct 2026 10:41:18 -0800
Subject: [PATCH] fix: keep newly added singular embeds across form changes

A singular embed added with the "+" button disappeared on the next form
change when none of its fields rendered a named input, e.g. an embed with
only array fields and no values yet. The change params then had no key
for the embed, so cast_embed fell back to the record's nil value.

Stop skipping the hidden fields inputs_for renders. The _persistent_id
keeps a singular embed's key in the params, and embeds with a primary key
now send their id, so cast_embed updates existing entries instead of
replacing them. skip_hidden only existed to keep these fields from
conflicting with the old empty-string removal input, which the drop param
has since replaced.
---
 lib/live_admin/components.ex                  |  2 +-
 test/live_admin/components/container_test.exs | 22 +++++++++++++++++++
 test/support/resources.ex                     | 10 +++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/live_admin/components.ex b/lib/live_admin/components.ex
index b0d16f7..b20db96 100644
--- a/lib/live_admin/components.ex
+++ b/lib/live_admin/components.ex
@@ -88,7 +88,7 @@ defmodule LiveAdmin.Components do
           <h2 class="embed-section-title">{@field |> humanize() |> trans()}</h2>
         </div>
         <%= if @value do %>
-          <.inputs_for :let={embed_form} field={@form[@field]} skip_hidden={true}>
+          <.inputs_for :let={embed_form} field={@form[@field]}>
             <%= if sortable?(@value) do %>
               <div class="drop-zone" data-idx={embed_form.index}>{trans("Move here")}</div>
             <% end %>
diff --git a/test/live_admin/components/container_test.exs b/test/live_admin/components/container_test.exs
index dd0acb2..d723193 100644
--- a/test/live_admin/components/container_test.exs
+++ b/test/live_admin/components/container_test.exs
@@ -262,6 +262,28 @@ defmodule LiveAdmin.Components.ContainerTest do
     end
   end
 
+  describe "edit resource after adding singular embed with only array fields" do
+    setup %{conn: conn} do
+      user = Repo.insert!(%User{})
+
+      {:ok, view, _} = live(conn, "/user/edit/#{user.id}")
+
+      view
+      |> element("form")
+      |> render_change(%{"params" => %{"private_data_sort" => "0"}})
+
+      view
+      |> element("form")
+      |> render_change(%{"params" => %{"name" => "test"}})
+
+      %{view: view}
+    end
+
+    test "keeps embed form field", %{view: view} do
+      assert has_element?(view, "#params_private_data_0_aliases_array_input")
+    end
+  end
+
   describe "edit resource with plural embed with multiple entries" do
     setup %{conn: conn} do
       post = Repo.insert!(%Post{title: "test", previous_versions: [%Version{}, %Version{}]})
diff --git a/test/support/resources.ex b/test/support/resources.ex
index 2d90dde..d68f459 100644
--- a/test/support/resources.ex
+++ b/test/support/resources.ex
@@ -37,6 +37,7 @@ defmodule LiveAdminTest.User do
     field(:encrypted_password, :string)
 
     embeds_one(:settings, LiveAdminTest.Settings)
+    embeds_one(:private_data, LiveAdminTest.PrivateData)
   end
 
   def user_task(_, _), do: {:ok, "worked"}
@@ -96,6 +97,15 @@ defmodule LiveAdminTest.Settings do
   end
 end
 
+defmodule LiveAdminTest.PrivateData do
+  use Ecto.Schema
+
+  @primary_key false
+  embedded_schema do
+    field(:aliases, {:array, :string})
+  end
+end
+
 defmodule LiveAdminTest.Post.Version do
   use Ecto.Schema