fix: support associations without an id

lib/live_sync/replication_test.exs

@@ -7,7 +7,7 @@ defmodule LiveSync.ReplicationTest do
   alias LiveSync.Replication
   alias LiveSync.Repo
 
-  @moduletag cleanup: ["ignored", "examples"]
+  @moduletag cleanup: ["example_tags", "ignored", "examples"]
 
   setup do
     LiveSync.start_link(repo: Repo, otp_app: :live_sync)

lib/live_sync/socket.ex

@@ -69,10 +69,10 @@ defmodule LiveSync.Socket do
           :delete
 
         %{} = value ->
-          {schema, id} = LiveSync.lookup_info(value)
+          lookup = LiveSync.lookup_info(value)
 
           Enum.find_value(operations, fn {op, record} ->
-            if record.__struct__ == schema and record.id == id do
+            if LiveSync.lookup_info(record) == lookup do
               op
             end
           end)
@@ -206,9 +206,9 @@ defmodule LiveSync.Socket do
         update.__struct__ == assoc.related and
           Map.get(update, assoc.related_key) != Map.get(parent, assoc.owner_key)
       end)
-      |> Enum.map(fn {_lookup, {_op, update}} -> update.id end)
+      |> Enum.map(fn {lookup, {_op, _update}} -> lookup end)
 
-    Enum.filter(list, &(is_map(&1) && &1.id not in records_to_remove))
+    Enum.filter(list, &(is_map(&1) && LiveSync.lookup_info(&1) not in records_to_remove))
   end
 
   defp maybe_remove_from_association(record, _parent, _assoc, _updates), do: record

lib/live_sync/socket_test.exs

@@ -2,6 +2,7 @@ defmodule LiveSync.SocketTest do
   use LiveSync.ConnCase
 
   alias LiveSync.Example
+  alias LiveSync.ExampleTag
   alias LiveSync.Ignored
   alias LiveSync.Repo
 
@@ -179,6 +180,25 @@ defmodule LiveSync.SocketTest do
            ] == Floki.find(parsed_html, ".data-child-name")
   end
 
+  test "works with associations without an id", %{conn: conn} do
+    example = Repo.insert!(%Example{organization_id: 1, name: "replication", enabled: false})
+    Repo.insert!(%ExampleTag{name: "tag", example_id: example.id})
+
+    {:ok, view, html} = conn |> get("/#{example.id}") |> live()
+
+    parsed_html = Floki.parse_document!(html)
+    assert parsed_html |> Floki.find(".data-tag-name") |> Floki.text() == "tag"
+
+    Repo.update!(change(example, name: "more replication"))
+
+    assert_receive :synced
+    html = render(view)
+
+    parsed_html = Floki.parse_document!(html)
+    assert parsed_html |> Floki.find("#data-name") |> Floki.text() == "more replication"
+    assert parsed_html |> Floki.find(".data-tag-name") |> Floki.text() == "tag"
+  end
+
   test "ignores non-watched schemas", %{conn: conn} do
     example = Repo.insert!(%Example{organization_id: 1, name: "replication", enabled: false})
     ignore = Repo.insert!(%Ignored{organization_id: 1, name: "ignore", example_id: example.id})

lib/test_helper.exs

@@ -1,6 +1,7 @@
 LiveSync.Repo.start_link()
 LiveSync.Endpoint.start_link()
 
+LiveSync.Repo.query!("DROP TABLE IF EXISTS example_tags;")
 LiveSync.Repo.query!("DROP TABLE IF EXISTS ignored;")
 LiveSync.Repo.query!("DROP TABLE IF EXISTS examples;")
 LiveSync.Repo.query("DROP PUBLICATION live_sync;")
@@ -28,6 +29,14 @@ CREATE TABLE ignored (
 );
 """)
 
+LiveSync.Repo.query!("""
+CREATE TABLE example_tags (
+  name text,
+  example_id bytea REFERENCES examples(id),
+  PRIMARY KEY (name, example_id)
+);
+""")
+
 Ecto.Migration.Runner.run(LiveSync.Repo, LiveSync.Repo.config(), 1, LiveSync.Migration, :forward, :up, :up, [])
 
 ExUnit.start(capture_log: true)

mix.exs

@@ -4,7 +4,7 @@ defmodule LiveSync.MixProject do
   def project do
     [
       app: :live_sync,
-      version: "0.1.11",
+      version: "0.1.12",
       elixir: "~> 1.17",
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,

test/support/example.ex

@@ -26,6 +26,7 @@ defmodule LiveSync.Example do
     belongs_to :parent, LiveSync.Example, type: :binary_id, foreign_key: :parent_id
     has_many :children, LiveSync.Example, foreign_key: :parent_id
     has_many :ignored, LiveSync.Ignored, foreign_key: :example_id
+    has_many :example_tags, LiveSync.ExampleTag, foreign_key: :example_id
   end
 
   def changeset(struct \\ %__MODULE__{}, params) do

test/support/example_tag.ex

@@ -0,0 +1,13 @@
+defmodule LiveSync.ExampleTag do
+  @moduledoc false
+  use Ecto.Schema
+
+  # a join style schema with a composite primary key and no `id` field
+  @primary_key false
+
+  schema "example_tags" do
+    field :name, :string, primary_key: true
+
+    belongs_to :example, LiveSync.Example, type: :binary_id, foreign_key: :example_id, primary_key: true
+  end
+end

test/support/live_page.ex

@@ -12,7 +12,7 @@ defmodule LiveSync.LivePage do
   alias LiveSync.Repo
 
   def mount(%{"id" => id}, session, socket) do
-    data = LiveSync.Example |> Repo.get!(id) |> Repo.preload([:parent, :children, :ignored])
+    data = LiveSync.Example |> Repo.get!(id) |> Repo.preload([:parent, :children, :ignored, :example_tags])
     {:ok, assign(socket, examples: [data], data: data, test: session["test"])}
   end
 
@@ -36,6 +36,7 @@ defmodule LiveSync.LivePage do
       <p :if={not is_nil(@data.parent)} id="data-parent-name">{@data.parent.name}</p>
       <p :for={child <- @data.children} class="data-child-name">{child.name}</p>
       <p :for={ignored <- @data.ignored} class="data-ignored-name">{ignored.name}</p>
+      <p :for={tag <- @data.example_tags} class="data-tag-name">{tag.name}</p>
     </div>
     <div id="examples">
       <div :for={example <- @examples}>