From 9f3ea5856abad6e497cb512076400960a30504e5 Mon Sep 17 00:00:00 2001
From: Linus <linus.dm@gmail.com>
Date: Mon, 23 Jan 2023 22:14:40 +0100
Subject: [PATCH] Check attached node elixir version (#1654)

The attached node should have a minimum elixir version, to avoid
problems at runtime.

For example, Livebook version 0.8 introduced a dependency on
`Code.eval_quoted_with_env/4` which is new since elixir 1.14.2.
---
 lib/livebook/runtime/attached.ex | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/lib/livebook/runtime/attached.ex b/lib/livebook/runtime/attached.ex
index bf58dd45f..1ed4b2bd9 100644
--- a/lib/livebook/runtime/attached.ex
+++ b/lib/livebook/runtime/attached.ex
@@ -39,17 +39,30 @@ defmodule Livebook.Runtime.Attached do
     # Set cookie for connecting to this specific node
     Node.set_cookie(node, cookie)
 
-    case Node.ping(node) do
-      :pong ->
-        server_pid =
-          Livebook.Runtime.ErlDist.initialize(node,
-            node_manager_opts: [parent_node: node(), capture_orphan_logs: false]
-          )
+    with :pong <- Node.ping(node),
+         :ok <- check_attached_node_version(node) do
+      server_pid =
+        Livebook.Runtime.ErlDist.initialize(node,
+          node_manager_opts: [parent_node: node(), capture_orphan_logs: false]
+        )
 
-        {:ok, %{runtime | node: node, server_pid: server_pid}}
+      {:ok, %{runtime | node: node, server_pid: server_pid}}
+    else
+      :pang -> {:error, "node #{inspect(node)} is unreachable"}
+      {:error, msg} -> {:error, msg}
+    end
+  end
 
-      :pang ->
-        {:error, "node #{inspect(node)} is unreachable"}
+  @elixir_version_requirement Keyword.fetch!(Mix.Project.config(), :elixir)
+
+  defp check_attached_node_version(node) do
+    attached_node_version = :erpc.call(node, System, :version, [])
+
+    if Version.match?(attached_node_version, @elixir_version_requirement) do
+      :ok
+    else
+      {:error,
+       "the node uses Elixir #{attached_node_version}, but #{@elixir_version_requirement} is required"}
     end
   end