Remove Singleton from formatters

This will make it trivial to reload the rubocop config for Shopify#1457 without doing an
awkward `Singleton.__init__`.
With `GlobalState` being a thing now, I don't see the need for a singleton

ADDONS.md

@@ -222,15 +222,13 @@ class MyFormatterRubyLspAddon < RubyLsp::Addon
   def activate(global_state, message_queue)
     # The first argument is an identifier users can pick to select this formatter. To use this formatter, users must
     # have rubyLsp.formatter configured to "my_formatter"
-    # The second argument is a singleton instance that implements the `FormatterRunner` interface (see below)
-    global_state.register_formatter("my_formatter", MyFormatterRunner.instance)
+    # The second argument is a class instance that implements the `FormatterRunner` interface (see below)
+    global_state.register_formatter("my_formatter", MyFormatterRunner.new)
   end
 end
 
 # Custom formatter
 class MyFormatter
-  # Make it a singleton class
-  include Singleton
   # If using Sorbet to develop the addon, then include this interface to make sure the class is properly implemented
   include RubyLsp::Requests::Support::Formatter
 

lib/ruby_lsp/requests/support/rubocop_formatter.rb

@@ -3,15 +3,12 @@
 
 return unless defined?(RubyLsp::Requests::Support::RuboCopRunner)
 
-require "singleton"
-
 module RubyLsp
   module Requests
     module Support
       class RuboCopFormatter
         extend T::Sig
         include Formatter
-        include Singleton
 
         sig { void }
         def initialize

lib/ruby_lsp/requests/support/syntax_tree_formatter.rb

@@ -8,15 +8,12 @@
   return
 end
 
-require "singleton"
-
 module RubyLsp
   module Requests
     module Support
       # :nodoc:
       class SyntaxTreeFormatter
         extend T::Sig
-        include Singleton
         include Support::Formatter
 
         sig { void }

lib/ruby_lsp/server.rb

@@ -248,10 +248,10 @@ def run_initialized
       end
 
       if defined?(Requests::Support::RuboCopFormatter)
-        @global_state.register_formatter("rubocop", Requests::Support::RuboCopFormatter.instance)
+        @global_state.register_formatter("rubocop", Requests::Support::RuboCopFormatter.new)
       end
       if defined?(Requests::Support::SyntaxTreeFormatter)
-        @global_state.register_formatter("syntax_tree", Requests::Support::SyntaxTreeFormatter.instance)
+        @global_state.register_formatter("syntax_tree", Requests::Support::SyntaxTreeFormatter.new)
       end
 
       perform_initial_indexing(indexing_config)

test/requests/code_actions_formatting_test.rb

@@ -79,7 +79,7 @@ def assert_corrects_to_expected(diagnostic_code, code_action_title, source, expe
     global_state.formatter = "rubocop"
     global_state.register_formatter(
       "rubocop",
-      RubyLsp::Requests::Support::RuboCopFormatter.instance,
+      RubyLsp::Requests::Support::RuboCopFormatter.new,
     )
 
     diagnostics = RubyLsp::Requests::Diagnostics.new(global_state, document).perform

test/requests/diagnostics_expectations_test.rb

@@ -14,7 +14,7 @@ def run_expectations(source)
     global_state.formatter = "rubocop"
     global_state.register_formatter(
       "rubocop",
-      RubyLsp::Requests::Support::RuboCopFormatter.instance,
+      RubyLsp::Requests::Support::RuboCopFormatter.new,
     )
 
     stdout, _ = capture_io do

test/requests/diagnostics_test.rb

@@ -9,7 +9,7 @@ def setup
     @global_state.formatter = "rubocop"
     @global_state.register_formatter(
       "rubocop",
-      RubyLsp::Requests::Support::RuboCopFormatter.instance,
+      RubyLsp::Requests::Support::RuboCopFormatter.new,
     )
   end
 
@@ -78,7 +78,6 @@ def foo
     RUBY
 
     formatter_class = Class.new do
-      include Singleton
       include RubyLsp::Requests::Support::Formatter
 
       def run_diagnostic(uri, document)
@@ -96,7 +95,7 @@ def run_diagnostic(uri, document)
       end
     end
 
-    @global_state.register_formatter("my-custom-formatter", T.unsafe(formatter_class).instance)
+    @global_state.register_formatter("my-custom-formatter", T.unsafe(formatter_class).new)
     @global_state.formatter = "my-custom-formatter"
 
     diagnostics = T.must(RubyLsp::Requests::Diagnostics.new(@global_state, document).perform)

test/requests/formatting_expectations_test.rb

@@ -12,7 +12,7 @@ def run_expectations(source)
     global_state.formatter = "rubocop"
     global_state.register_formatter(
       "rubocop",
-      RubyLsp::Requests::Support::RuboCopFormatter.instance,
+      RubyLsp::Requests::Support::RuboCopFormatter.new,
     )
     document = RubyLsp::RubyDocument.new(source: source, version: 1, uri: URI::Generic.from_path(path: __FILE__))
     RubyLsp::Requests::Formatting.new(global_state, document).perform&.first&.new_text

test/requests/formatting_test.rb

@@ -9,11 +9,11 @@ def setup
     @global_state.formatter = "rubocop"
     @global_state.register_formatter(
       "rubocop",
-      RubyLsp::Requests::Support::RuboCopFormatter.instance,
+      RubyLsp::Requests::Support::RuboCopFormatter.new,
     )
     @global_state.register_formatter(
       "syntax_tree",
-      RubyLsp::Requests::Support::SyntaxTreeFormatter.instance,
+      RubyLsp::Requests::Support::SyntaxTreeFormatter.new,
     )
     @document = RubyLsp::RubyDocument.new(source: +<<~RUBY, version: 1, uri: URI::Generic.from_path(path: __FILE__))
       class Foo
@@ -141,17 +141,15 @@ def test_returns_nil_when_formatter_is_invalid
   end
 
   def test_using_a_custom_formatter
-    require "singleton"
     formatter_class = Class.new do
-      include Singleton
       include RubyLsp::Requests::Support::Formatter
 
       def run_formatting(uri, document)
         "#{document.source}\n# formatter by my-custom-formatter"
       end
     end
 
-    @global_state.register_formatter("my-custom-formatter", T.unsafe(formatter_class).instance)
+    @global_state.register_formatter("my-custom-formatter", T.unsafe(formatter_class).new)
     assert_includes(formatted_document("my-custom-formatter"), "# formatter by my-custom-formatter")
   end
 
@@ -181,10 +179,9 @@ def with_syntax_tree_config_file(contents)
   def clear_syntax_tree_runner_singleton_instance
     return unless defined?(RubyLsp::Requests::Support::SyntaxTreeFormatter)
 
-    Singleton.__init__(RubyLsp::Requests::Support::SyntaxTreeFormatter)
     @global_state.register_formatter(
       "syntax_tree",
-      RubyLsp::Requests::Support::SyntaxTreeFormatter.instance,
+      RubyLsp::Requests::Support::SyntaxTreeFormatter.new,
     )
   end
 end

test/server_test.rb

@@ -410,31 +410,31 @@ def test_sets_formatter_to_none_if_neither_rubocop_or_syntax_tree_are_present
   end
 
   def test_shows_error_if_formatter_set_to_rubocop_but_rubocop_not_available
-    capture_subprocess_io do
-      @server.process_message(id: 1, method: "initialize", params: {
-        initializationOptions: { formatter: "rubocop" },
-      })
+    # capture_subprocess_io do
+    @server.process_message(id: 1, method: "initialize", params: {
+      initializationOptions: { formatter: "rubocop" },
+    })
 
-      @server.global_state.register_formatter("rubocop", RubyLsp::Requests::Support::RuboCopFormatter.instance)
-      with_uninstalled_rubocop do
-        @server.process_message({ method: "initialized" })
-      end
+    @server.global_state.register_formatter("rubocop", RubyLsp::Requests::Support::RuboCopFormatter.new)
+    with_uninstalled_rubocop do
+      @server.process_message({ method: "initialized" })
+    end
 
-      assert_equal("none", @server.global_state.formatter)
+    assert_equal("none", @server.global_state.formatter)
 
-      # Remove the initialization notifications
-      @server.pop_response
-      @server.pop_response
-      @server.pop_response
+    # Remove the initialization notifications
+    @server.pop_response
+    @server.pop_response
+    @server.pop_response
 
-      notification = @server.pop_response
+    notification = @server.pop_response
 
-      assert_equal("window/showMessage", notification.method)
-      assert_equal(
-        "Ruby LSP formatter is set to `rubocop` but RuboCop was not found in the Gemfile or gemspec.",
-        T.cast(notification.params, RubyLsp::Interface::ShowMessageParams).message,
-      )
-    end
+    assert_equal("window/showMessage", notification.method)
+    assert_equal(
+      "Ruby LSP formatter is set to `rubocop` but RuboCop was not found in the Gemfile or gemspec.",
+      T.cast(notification.params, RubyLsp::Interface::ShowMessageParams).message,
+    )
+    # end
   end
 
   def test_initialize_sets_client_name
@@ -480,20 +480,25 @@ def with_uninstalled_rubocop(&block)
     rubocop_paths = $LOAD_PATH.select { |path| path.include?("gems/rubocop") }
     rubocop_paths.each { |path| $LOAD_PATH.delete(path) }
 
-    $LOADED_FEATURES.delete_if { |path| path.include?("ruby_lsp/requests/support/rubocop_runner") }
+    $LOADED_FEATURES.delete_if do |path|
+      path.include?("ruby_lsp/requests/support/rubocop_runner") ||
+        path.include?("ruby_lsp/requests/support/rubocop_formatter")
+    end
 
     unload_rubocop_runner
     block.call
   ensure
     $LOAD_PATH.unshift(*rubocop_paths)
     unload_rubocop_runner
     require "ruby_lsp/requests/support/rubocop_runner"
+    require "ruby_lsp/requests/support/rubocop_formatter"
   end
 
   def unload_rubocop_runner
     RubyLsp::Requests::Support.send(:remove_const, :RuboCopRunner)
+    RubyLsp::Requests::Support.send(:remove_const, :RuboCopFormatter)
   rescue NameError
-    # Depending on which tests have run prior to this one, `RuboCopRunner` may or may not be defined
+    # Depending on which tests have run prior to this one, the classes may or may not be defined
   end
 
   def stub_dependencies(rubocop:, syntax_tree:)