Use Prism for Ruby source parsing on Ruby >= 3.3

lib/console1984.rb

@@ -55,6 +55,28 @@ class << self
     def running_protected_environment?
       protected_environments.collect(&:to_sym).include?(Rails.env.to_sym)
     end
+
+    def require_ruby_parser_dependencies
+      if RUBY_VERSION >= "3.3"
+        require 'parser'
+        require 'prism'
+      else
+        Kernel.silence_warnings do
+          require 'parser/current'
+        end
+      end
+    end
+
+    # Returns the parser class used for parsing console commands.
+    # Uses Prism on Ruby >= 3.3 for forward-compatibility with Ruby 4.0+.
+    # Falls back to the parser gem on older Rubies.
+    def ruby_parser
+      if RUBY_VERSION >= "3.3"
+        Prism::Translation::ParserCurrent
+      else
+        Parser::CurrentRuby
+      end
+    end
   end
 end
 

lib/console1984/command_validator/.command_parser.rb

@@ -1,7 +1,7 @@
 # Naming class with dot so that it doesn't get loaded eagerly by Zeitwerk. We want to load
-# only when a console session is started, when +parser+ is loaded.
-#
-# See +Console1984::Supervisor#require_dependencies+
+# only when a console session is started.
+Console1984.require_ruby_parser_dependencies
+
 class Console1984::CommandValidator::CommandParser < ::Parser::AST::Processor
   include AST::Processor::Mixin
   include Console1984::Freezeable

lib/console1984/command_validator/parsed_command.rb

@@ -1,6 +1,4 @@
 # Parses a command string and exposes different constructs to be used by validations.
-#
-# Internally, it uses the {parser}[https://github.com/whitequark/parser] gem to perform the parsing.
 class Console1984::CommandValidator::ParsedCommand
   include Console1984::Freezeable
 
@@ -15,7 +13,7 @@ def initialize(raw_command)
   private
     def command_parser
       @command_parser ||= Console1984::CommandValidator::CommandParser.new.tap do |processor|
-        ast = Parser::CurrentRuby.parse(raw_command)
+        ast = Console1984.ruby_parser.parse(raw_command)
         processor.process(ast)
       rescue Parser::SyntaxError
         # Fail open with syntax errors

lib/console1984/refrigerator.rb

@@ -27,6 +27,6 @@ def freeze_external_modules_and_classes
 
     def external_modules_and_classes_to_freeze
       # Not using a constant because we want this to run lazily (console-dependant dependencies might not be loaded).
-      [Parser::CurrentRuby]
+      [Console1984.ruby_parser]
     end
 end

lib/console1984/supervisor.rb

@@ -41,13 +41,7 @@ def current_username
 
   private
     def require_dependencies
-      Kernel.silence_warnings do
-        require 'parser/current'
-      end
       require 'rainbow'
-
-      # Explicit lazy loading because it depends on +parser+, which we want to only load
-      # in console sessions.
       require_relative "./command_validator/.command_parser"
 
       # This solves a weird class loading error where ActiveRecord dosn't resolve +Relation+ properly.

test/command_validator/forbidden_constant_reference_validation_test.rb

@@ -45,6 +45,14 @@ class ForbiddenConstantReferenceValidationTest < ActiveSupport::TestCase
     end
   end
 
+  test "validate assigning a forbidden constant to a new constant" do
+    assert_raise Console1984::Errors::ForbiddenCommandAttempted do
+      run_validation <<~RUBY, always: ["SomeClass"]
+        MyAlias = SomeClass
+      RUBY
+    end
+  end
+
   test "referencing other constants won't raise any error" do
     run_validation <<~RUBY, always: ["SomeConstant"]
       SomeNotForbiddenClass.some_method

test/command_validator/forbidden_reopening_validation_test.rb

@@ -37,6 +37,14 @@ module Some::Base::Class
     end
   end
 
+  test "validate assigning a forbidden class to a new constant" do
+    assert_raise Console1984::Errors::ForbiddenCommandAttempted do
+      run_validation <<~RUBY, ["SomeClass"]
+        MyAlias = SomeClass
+      RUBY
+    end
+  end
+
   test "doesn't prevent reopening classes when the constant is a partial match" do
     run_validation <<~RUBY, ["SomeClass"]
       class SomeClass2

test/command_validator/parsed_command_test.rb

@@ -72,6 +72,16 @@ class t::Subtopic
     end
   end
 
+  if RUBY_VERSION >= "4.0"
+    test "parse constants from Ruby 4.0 syntax" do
+      # Logical operators at line beginning is new syntax in Ruby 4.0
+      assert_constants ["Foo", "Bar"], <<~RB
+        result = Foo
+          || Bar
+      RB
+    end
+  end
+
   test "syntax errors are handled gracefully" do
     parsed_command = Console1984::CommandValidator::ParsedCommand.new <<~RB
       def 12'39u````

test/ruby_parser_test.rb

@@ -0,0 +1,11 @@
+require "test_helper"
+
+class RubyParserTest < ActiveSupport::TestCase
+  test "ruby_parser returns the appropriate parser for the current Ruby version" do
+    if RUBY_VERSION >= "3.3"
+      assert_equal Prism::Translation::ParserCurrent, Console1984.ruby_parser
+    else
+      assert_equal Parser::CurrentRuby, Console1984.ruby_parser
+    end
+  end
+end

test/test_helper.rb

@@ -8,7 +8,6 @@
 require "rails/test_help"
 require "mocha/minitest"
 require "minitest/mock"
-require "parser/current"
 require "activeresource"
 require "ostruct"