Recover from uninstalled gems in launcher mode (#2975)

Author: vinistock

lib/ruby_lsp/setup_bundler.rb

@@ -241,16 +241,16 @@ def run_bundle_install(bundle_gemfile = @gemfile)
       env
     end
 
-    sig { params(env: T::Hash[String, String]).returns(T::Hash[String, String]) }
-    def run_bundle_install_directly(env)
+    sig { params(env: T::Hash[String, String], force_install: T::Boolean).returns(T::Hash[String, String]) }
+    def run_bundle_install_directly(env, force_install: false)
       RubyVM::YJIT.enable if defined?(RubyVM::YJIT.enable)
 
       # 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?
       T.unsafe(ENV).merge!(env)
 
-      unless should_update
+      unless should_update && !force_install
         Bundler::CLI::Install.new({}).run
         correct_relative_remote_paths if @custom_lockfile.exist?
         return env
@@ -265,6 +265,9 @@ def run_bundle_install_directly(env)
       correct_relative_remote_paths if @custom_lockfile.exist?
       @last_updated_path.write(Time.now.iso8601)
       env
+    rescue Bundler::GemNotFound, Bundler::GitError
+      # If a gem is not installed, skip the upgrade and try to install it with a single retry
+      @retry ? env : run_bundle_install_directly(env, force_install: true)
     end
 
     sig { params(env: T::Hash[String, String]).returns(T::Hash[String, String]) }

test/setup_bundler_test.rb

@@ -823,6 +823,41 @@ 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({}).returns(mock_install)
+
+            RubyLsp::SetupBundler.new(dir, launcher: true).setup!
+          end
+        end
+
+        refute_path_exists(File.join(".ruby-lsp", "install_error"))
+      end
+    end
+  end
+
   private
 
   def with_default_external_encoding(encoding, &block)