Improve error messages caused by invalid module names (#74)

Fixes #66

Author: magnetised

lib/phoenix/sync/predefined_shape.ex

@@ -126,9 +126,15 @@ defmodule Phoenix.Sync.PredefinedShape do
   end
 
   defp from_queryable!(%{query: queryable} = predefined_shape) do
-    queryable
-    |> Electric.Client.EctoAdapter.shape_from_query!()
-    |> from_shape_definition(predefined_shape)
+    try do
+      queryable
+      |> Electric.Client.EctoAdapter.shape_from_query!()
+      |> from_shape_definition(predefined_shape)
+    rescue
+      e in Protocol.UndefinedError ->
+        raise ArgumentError,
+          message: "Invalid query `#{inspect(queryable)}`: #{e.description}"
+    end
   end
 
   defp from_shape_definition(%ShapeDefinition{} = shape_definition, predefined_shape) do

test/phoenix/sync/router_test.exs

@@ -63,6 +63,8 @@ defmodule Phoenix.Sync.RouterTest do
       # query version also accepts shape config
       sync "/query-config", Support.Todo, replica: :full
       sync "/query-config2", Support.Todo, replica: :full, storage: %{compaction: :disabled}
+
+      sync "/typo", Support.Todoo
     end
 
     scope "/namespaced-sync", WebNamespace do
@@ -90,7 +92,7 @@ defmodule Phoenix.Sync.RouterTest do
     :configure_endpoint
   ]
 
-  describe "Phoenix.Router - shape/2" do
+  describe "Phoenix.Router - sync/2" do
     @tag table: {
            "todos",
            [
@@ -375,6 +377,15 @@ defmodule Phoenix.Sync.RouterTest do
 
       assert ["0"] = Plug.Conn.get_resp_header(resp, "electric-cursor")
     end
+
+    test "raises clear error error if the schema module is not found" do
+      assert_raise ArgumentError,
+                   ~r/Invalid query `Support.Todoo`: the given module does not exist/,
+                   fn ->
+                     Phoenix.ConnTest.build_conn()
+                     |> Phoenix.ConnTest.get("/sync/typo", %{offset: "-1"})
+                   end
+    end
   end
 
   describe "Plug.Router - shape/2" do

test/support/endpoint.ex

@@ -39,3 +39,9 @@ defmodule Phoenix.Sync.LiveViewTest.Endpoint do
     Exception.message(conn.reason)
   end
 end
+
+defmodule Phoenix.ErrorView do
+  def render("500.html", %{reason: exception}) do
+    Exception.message(exception)
+  end
+end