From b39b61dd11e991d291e99ab13d66663968398c91 Mon Sep 17 00:00:00 2001
From: Stan Lo <stan.lo@shopify.com>
Date: Fri, 8 Mar 2024 17:11:45 +0800
Subject: [PATCH] Specifically handle the case where bin/rails is not found

When the file is not found, it is likely that the LSP is not being run in
the root of a Rails project. Having a more specific error message will
help the user understand what is going on.
---
 lib/ruby_lsp/ruby_lsp_rails/runner_client.rb | 10 +++++++++-
 test/ruby_lsp_rails/runner_client_test.rb    | 20 +++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb b/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
index 9c316cd2..649fc1b7 100644
--- a/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
+++ b/lib/ruby_lsp/ruby_lsp_rails/runner_client.rb
@@ -12,7 +12,15 @@ class << self
 
         sig { returns(RunnerClient) }
         def create_client
-          new
+          if File.exist?("bin/rails")
+            new
+          else
+            warn(<<~MSG)
+              Ruby LSP Rails failed to locate bin/rails in the current directory: #{Dir.pwd}"
+            MSG
+            warn("Server dependent features will not be available")
+            NullClient.new
+          end
         rescue Errno::ENOENT, StandardError => e # rubocop:disable Lint/ShadowedException
           warn("Ruby LSP Rails failed to initialize server: #{e.message}\n#{e.backtrace&.join("\n")}")
           warn("Server dependent features will not be available")
diff --git a/test/ruby_lsp_rails/runner_client_test.rb b/test/ruby_lsp_rails/runner_client_test.rb
index 92f96717..ff96f8e2 100644
--- a/test/ruby_lsp_rails/runner_client_test.rb
+++ b/test/ruby_lsp_rails/runner_client_test.rb
@@ -39,10 +39,28 @@ class RunnerClientTest < ActiveSupport::TestCase
         assert_nil @client.model("ApplicationRecord") # ApplicationRecord is abstract
       end
 
+      test "falls back to null client when bin/rails is not found" do
+        FileUtils.mv("bin/rails", "bin/rails_backup")
+
+        assert_output("", %r{Ruby LSP Rails failed to locate bin/rails in the current directory}) do
+          client = RunnerClient.create_client
+
+          assert_instance_of(NullClient, client)
+          assert_nil(client.model("User"))
+          assert_predicate(client, :stopped?)
+        end
+      ensure
+        FileUtils.mv("bin/rails_backup", "bin/rails")
+      end
+
       test "failing to spawn server creates a null client" do
         FileUtils.mv("bin/rails", "bin/rails_backup")
+        File.open("bin/rails", "w") do |f|
+          f.write("foo")
+        end
+        File.chmod(0o755, "bin/rails")
 
-        assert_output("", %r{No such file or directory - bin/rails}) do
+        assert_output("", %r{uby LSP Rails failed to initialize server: bin/rails: line 1: foo: command not found}) do
           client = RunnerClient.create_client
 
           assert_instance_of(NullClient, client)