From 9db724334707f10af74f627047737ffcdd913c2d Mon Sep 17 00:00:00 2001
From: Greg Rychlewski <greg.rychlewski@gmail.com>
Date: Thu, 21 Sep 2023 21:21:14 -0400
Subject: [PATCH] raise when trying to count a source

---
 lib/ecto/adapters/sqlite3/connection.ex             |  6 ++++++
 .../adapters/sqlite3/connection/aggregates_test.exs | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/ecto/adapters/sqlite3/connection.ex b/lib/ecto/adapters/sqlite3/connection.ex
index b689e9a..b9d457b 100644
--- a/lib/ecto/adapters/sqlite3/connection.ex
+++ b/lib/ecto/adapters/sqlite3/connection.ex
@@ -1375,6 +1375,12 @@ defmodule Ecto.Adapters.SQLite3.Connection do
 
   def expr({:count, _, []}, _sources, _query), do: "count(*)"
 
+  def expr({:count, _, [{:&, _, [_]}]}, _sources, query) do
+    raise Ecto.QueryError,
+      query: query,
+      message: "The argument to `count/1` must be a column in SQLite3"
+  end
+
   def expr({:json_extract_path, _, [expr, path]}, sources, query) do
     path =
       Enum.map(path, fn
diff --git a/test/ecto/adapters/sqlite3/connection/aggregates_test.exs b/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
index 56c7d35..2aa1a11 100644
--- a/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
+++ b/test/ecto/adapters/sqlite3/connection/aggregates_test.exs
@@ -15,6 +15,19 @@ defmodule Ecto.Adapters.SQLite3.Connection.AggregatesTest do
     assert ~s{SELECT count(s0."x") FROM "schema" AS s0} == all(query)
   end
 
+  test "raises when counting a source" do
+    query =
+      Schema
+      |> select([r], count(r))
+      |> plan()
+
+    msg = ~r"The argument to `count/1` must be a column in SQLite3"
+
+    assert_raise Ecto.QueryError, msg, fn ->
+      all(query)
+    end
+  end
+
   test "raises when trying to distinct count" do
     assert_raise Ecto.QueryError, fn ->
       Schema