Return nil on empty response

lib/ruby_lsp/ruby_lsp_rails/runner_client.rb

@@ -70,32 +70,27 @@ def initialize(outgoing_queue)
           # https://github.com/Shopify/ruby-lsp-rails/issues/348
         end
 
+        log_message("Ruby LSP Rails booting server")
+
         stdin, stdout, stderr, wait_thread = Bundler.with_original_env do
           Open3.popen3("bundle", "exec", "rails", "runner", "#{__dir__}/server.rb", "start")
         end
 
         @stdin = T.let(stdin, IO)
         @stdout = T.let(stdout, IO)
         @stderr = T.let(stderr, IO)
+        @stdin.sync = true
+        @stdout.sync = true
+        @stderr.sync = true
         @wait_thread = T.let(wait_thread, Process::Waiter)
 
         # We set binmode for Windows compatibility
         @stdin.binmode
         @stdout.binmode
         @stderr.binmode
 
-        log_message("Ruby LSP Rails booting server")
-        count = 0
-
-        begin
-          count += 1
-          initialize_response = T.must(read_response)
-          @rails_root = T.let(initialize_response[:root], String)
-        rescue EmptyMessageError
-          log_message("Ruby LSP Rails is retrying initialize (#{count})")
-          retry if count < MAX_RETRIES
-        end
-
+        initialize_response = T.must(read_response)
+        @rails_root = T.let(initialize_response[:root], String)
         log_message("Finished booting Ruby LSP Rails server")
 
         unless ENV["RAILS_ENV"] == "test"
@@ -274,11 +269,9 @@ def send_message(request, **params)
       sig { overridable.returns(T.nilable(T::Hash[Symbol, T.untyped])) }
       def read_response
         raw_response = @mutex.synchronize do
-          headers = @stdout.gets("\r\n\r\n")
-          raise IncompleteMessageError unless headers
-
-          content_length = headers[/Content-Length: (\d+)/i, 1].to_i
-          raise EmptyMessageError if content_length.zero?
+          content_length = read_content_length
+          content_length = read_content_length unless content_length
+          raise EmptyMessageError unless content_length
 
           @stdout.read(content_length)
         end
@@ -311,6 +304,17 @@ def log_message(message, type: RubyLsp::Constant::MessageType::LOG)
 
         @outgoing_queue << RubyLsp::Notification.window_log_message(message, type: type)
       end
+
+      sig { returns(T.nilable(Integer)) }
+      def read_content_length
+        headers = @stdout.gets("\r\n\r\n")
+        return unless headers
+
+        length = headers[/Content-Length: (\d+)/i, 1]
+        return unless length
+
+        length.to_i
+      end
     end
 
     class NullClient < RunnerClient

test/ruby_lsp_rails/launch_test.rb

@@ -0,0 +1,27 @@
+# typed: true
+# frozen_string_literal: true
+
+require "test_helper"
+
+module RubyLsp
+  module Rails
+    class LaunchTest < ActiveSupport::TestCase
+      test "launching the client succeeds" do
+        outgoing_queue = Thread::Queue.new
+
+        client = RunnerClient.create_client(outgoing_queue)
+        refute_instance_of(NullClient, client)
+
+        first = pop_log_notification(outgoing_queue, Constant::MessageType::LOG)
+        assert_equal("Ruby LSP Rails booting server", first.params.message)
+
+        second = pop_log_notification(outgoing_queue, Constant::MessageType::LOG)
+        assert_match("Finished booting Ruby LSP Rails server", second.params.message)
+
+        client.shutdown
+        assert_predicate(client, :stopped?)
+        outgoing_queue.close
+      end
+    end
+  end
+end

test/ruby_lsp_rails/runner_client_test.rb

@@ -87,17 +87,16 @@ class RunnerClientTest < ActiveSupport::TestCase
         junk = %{\nputs "1\r\n\r\nhello"}
         File.write("test/dummy/config/application.rb", content + junk)
 
-        capture_subprocess_io do
-          outgoing_queue = Thread::Queue.new
-          client = RunnerClient.create_client(outgoing_queue)
+        outgoing_queue = Thread::Queue.new
+        client = RunnerClient.create_client(outgoing_queue)
+        response = client.model("User")
 
-          response = T.must(client.model("User"))
-          assert(response.key?(:columns))
+        begin
+          assert(T.must(response).key?(:columns))
         ensure
           T.must(outgoing_queue).close
+          FileUtils.mv("test/dummy/config/application.rb.bak", "test/dummy/config/application.rb")
         end
-      ensure
-        FileUtils.mv("test/dummy/config/application.rb.bak", "test/dummy/config/application.rb")
       end
 
       test "delegate notification" do
@@ -155,14 +154,6 @@ def execute(request, params)
       ensure
         FileUtils.rm("server_addon.rb")
       end
-
-      private
-
-      def pop_log_notification(message_queue, type)
-        log = message_queue.pop
-        log = message_queue.pop until log.params.type == type
-        log
-      end
     end
 
     class NullClientTest < ActiveSupport::TestCase

test/test_helper.rb

@@ -48,5 +48,13 @@ def pop_result(server)
       )
       T.cast(result, RubyLsp::Result)
     end
+
+    def pop_log_notification(message_queue, type)
+      log = message_queue.pop
+      return log if log.params.type == type
+
+      log = message_queue.pop until log.params.type == type
+      log
+    end
   end
 end