Avoid running bundle install unless necessary

Author: vinistock

lib/ruby_lsp/server.rb

@@ -1435,6 +1435,8 @@ def compose_bundle(message)
 
     #: -> void
     def update_server
+      return unless @global_state.enabled_feature?(:launcher)
+
       launch_bundle_compose("Trying to update server") do |stderr, status|
         if status&.exitstatus == 0
           send_log_message("Successfully updated the server")

lib/ruby_lsp/setup_bundler.rb

@@ -260,13 +260,36 @@ def run_bundle_install_directly(env, force_install: false)
 
       # The ENV can only be merged after checking if an update is required because we depend on the original value of
       # ENV["BUNDLE_GEMFILE"], which gets overridden after the merge
-      should_update = should_bundle_update?
+      FileUtils.touch(@custom_dir + "needs_update") if should_bundle_update?
       ENV.merge!(env)
 
+      $stderr.puts("Ruby LSP> Checking if the composed bundle is satisfied...")
+      definition = Bundler.definition
+      definition.validate_runtime!
+      definition.check!
+      missing_gems = definition.missing_specs
+
+      unless missing_gems.empty?
+        $stderr.puts(<<~MESSAGE)
+          Ruby LSP> Running bundle install because the following gems are not installed:
+          #{missing_gems.map { |g| "#{g.name}: #{g.version}" }.join("\n")}
+        MESSAGE
+
+        bundle_install
+      end
+
+      $stderr.puts("Ruby LSP> Bundle already satisfied")
+      env
+    rescue => e
+      $stderr.puts("Ruby LSP> Running bundle install because #{e.message}")
+      bundle_install
+      env
+    end
+
+    #: -> void
+    def bundle_install
       Bundler::CLI::Install.new({ "no-cache" => true }).run
       correct_relative_remote_paths if @custom_lockfile.exist?
-      FileUtils.touch(@custom_dir + "needs_update") if should_update
-      env
     end
 
     #: (Hash[String, String]) -> Hash[String, String]

test/setup_bundler_test.rb

@@ -694,6 +694,7 @@ def test_invoke_cli_calls_bundler_directly_for_install
             mock_install = mock("install")
             mock_install.expects(:run)
             Bundler::CLI::Install.expects(:new).with({ "no-cache" => true }).returns(mock_install)
+            Bundler::Definition.any_instance.expects(:check!).raises(StandardError.new("missing gems"))
             RubyLsp::SetupBundler.new(dir, launcher: true).setup!
           end
         end
@@ -728,6 +729,8 @@ def test_invoke_cli_calls_bundler_directly_for_update
               { conservative: true },
               ["ruby-lsp", "debug", "prism"],
             ).returns(mock_update)
+
+            FileUtils.touch(File.join(dir, ".ruby-lsp", "needs_update"))
             RubyLsp::SetupBundler.new(dir, launcher: true).setup!
           end
         end
@@ -749,6 +752,7 @@ def test_progress_is_printed_to_stderr
             system("bundle install")
           end
 
+          Bundler::Definition.any_instance.expects(:check!).raises(StandardError.new("missing gems"))
           stdout, stderr = capture_subprocess_io do
             RubyLsp::SetupBundler.new(dir, launcher: true).setup!
           end
@@ -844,41 +848,6 @@ def test_is_resilient_to_gemfile_changes_in_the_middle_of_setup
     end
   end
 
-  def test_update_does_not_fail_if_gems_are_uninstalled
-    Dir.mktmpdir do |dir|
-      Dir.chdir(dir) do
-        File.write(File.join(dir, "Gemfile"), <<~GEMFILE)
-          source "https://rubygems.org"
-          gem "rdoc"
-        GEMFILE
-
-        capture_subprocess_io do
-          Bundler.with_unbundled_env do
-            system("bundle install")
-            run_script(dir)
-
-            mock_update = mock("update")
-            mock_update.expects(:run).raises(Bundler::GemNotFound.new("rdoc"))
-            require "bundler/cli/update"
-            Bundler::CLI::Update.expects(:new).with(
-              { conservative: true },
-              ["ruby-lsp", "debug", "prism"],
-            ).returns(mock_update)
-
-            mock_install = mock("install")
-            mock_install.expects(:run)
-            require "bundler/cli/install"
-            Bundler::CLI::Install.expects(:new).with({ "no-cache" => true }).returns(mock_install)
-
-            RubyLsp::SetupBundler.new(dir, launcher: true).setup!
-          end
-        end
-
-        refute_path_exists(File.join(".ruby-lsp", "install_error"))
-      end
-    end
-  end
-
   def test_only_returns_environment_if_bundle_was_composed_ahead_of_time
     Dir.mktmpdir do |dir|
       Dir.chdir(dir) do