[WIP] Allow setting a target ruby version

.gitignore

@@ -9,3 +9,7 @@
 doc
 coverage
 /tmp/
+pkg/*
+.tool-versions
+.ruby-version
+.ruby_version

lib/solargraph/parser/parser_gem/class_methods.rb

@@ -14,6 +14,13 @@
 module Solargraph
   module Parser
     module ParserGem
+      FORCED_LEGACY_PARSERS = {
+        1 => (8..9),
+        2 => (0..7),
+        3 => (0..2)
+      }
+      MIN_MODERN_PARSER_VERSION = [3, 3]
+
       module ClassMethods
         # @param code [String]
         # @param filename [String, nil]
@@ -31,17 +38,67 @@ def parse_with_comments code, filename = nil
         def parse code, filename = nil, line = 0
           buffer = ::Parser::Source::Buffer.new(filename, line)
           buffer.source = code
-          parser.parse(buffer)
+          res = parser.parse(buffer)
+          parser.reset
+
+          res
         rescue ::Parser::SyntaxError, ::Parser::UnknownEncodingInMagicComment => e
+          parser.reset
+
           raise Parser::SyntaxError, e.message
         end
 
+        def parser_opts(parser)
+          parser.diagnostics.all_errors_are_fatal = true
+          parser.diagnostics.ignore_warnings      = true
+        end
+
+        # @param version [String] a presentation of the ruby version as a string
+        #   Eg. ruby 2.7.4 => 27
+        #       ruby 3.4   => 34
+        def modern_parser(version)
+          Solargraph.logger.info("Using modern ruby parser (#{version})")
+
+          Prism::Translation.const_get("Parser#{version}").new(FlawedBuilder.new).tap do |parser|
+            parser_opts(parser)
+          end
+        end
+
+        def legacy_parser(version)
+          Solargraph.logger.info("Using legacy ruby parser (#{version})")
+
+          require "parser/ruby#{version}"
+          parser = ::Parser.const_get("Ruby#{version}").new(FlawedBuilder.new)
+          parser_opts(parser)
+
+          parser
+        end
+
+        # Forces a new parser with a specified version of ruby
+        # @param ruby_version [String, :current]
         # @return [::Parser::Base]
-        def parser
-          @parser ||= Prism::Translation::Parser.new(FlawedBuilder.new).tap do |parser|
-            parser.diagnostics.all_errors_are_fatal = true
-            parser.diagnostics.ignore_warnings      = true
+        def force_new_parser(ruby_version = :current)
+          Solargraph.logger.debug("Trying to set new parser version for '#{ruby_version}'")
+
+          ruby_version = RUBY_VERSION if ruby_version == :current
+          major, minor = ruby_version.split('.').map(&:to_i)[..1]
+
+          if major >= MIN_MODERN_PARSER_VERSION[0] && minor >= MIN_MODERN_PARSER_VERSION[1]
+            # Modern parsers can be memoized, idk why legacy one can't be :/
+            @parser = modern_parser([major, minor].join)
+          elsif FORCED_LEGACY_PARSERS.key?(major) && FORCED_LEGACY_PARSERS[major].include?(minor)
+            @parser = legacy_parser([major, minor].join)
+          else
+            # Ruby < 3 is unsupported, so this shouldn't get into an infinite loop, ever
+            force_new_parser(:current)
           end
+
+          @parser
+        end
+
+        # @return [::Parser::Base]
+        def parser
+          @parser ||= force_new_parser
         end
 
         # @param source [Source]

lib/solargraph/workspace.rb

@@ -171,6 +171,8 @@ def source_hash
     # @return [void]
     def load_sources
       source_hash.clear
+      Solargraph::Parser.force_new_parser(config.ruby_version == 'current' ? :current : config.ruby_version)
+
       unless directory.empty? || directory == '*'
         size = config.calculated.length
         raise WorkspaceTooLargeError, "The workspace is too large to index (#{size} files, #{config.max_files} max)" if config.max_files > 0 and size > config.max_files

lib/solargraph/workspace/config.rb

@@ -111,6 +111,10 @@ def max_files
         raw_data['max_files']
       end
 
+      def ruby_version
+        raw_data['ruby_version']
+      end
+
       private
 
       # @return [String]
@@ -156,6 +160,7 @@ def default_config
           'require' => [],
           'domains' => [],
           'reporters' => %w[rubocop require_not_found],
+          'ruby_version' => 'current',
           'formatter' => {
             'rubocop' => {
               'cops' => 'safe',

spec/parser/node_chainer_spec.rb

@@ -163,18 +163,19 @@ class Foo
     expect(arg).to be_a(Solargraph::Source::Chain::BlockSymbol)
   end
 
-  # feature added in Ruby 3.1
-  if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.1')
-    it 'tracks anonymous block forwarding' do
-      source = Solargraph::Source.load_string(%(
+  it 'tracks anonymous block forwarding' do
+    Solargraph::Parser.force_new_parser('3.1') # (added in ruby 3.1)
+
+    source = Solargraph::Source.load_string(%(
       def foo(&)
         bar(&)
       end
     ))
-      anonymous_block_pass = source.node.children[2].children[2]
-      chain = Solargraph::Parser.chain(anonymous_block_pass)
-      block_variable_node = chain.links.first
-      expect(block_variable_node.word).to be_nil
-    end
+    anonymous_block_pass = source.node.children[2].children[2]
+    chain = Solargraph::Parser.chain(anonymous_block_pass)
+    block_variable_node = chain.links.first
+    expect(block_variable_node.word).to be_nil
+
+    Solargraph::Parser.force_new_parser(:current)
   end
 end

spec/parser_spec.rb

@@ -8,4 +8,53 @@
     code = "# encoding: utf-\nx = 'y'"
     expect { Solargraph::Parser.parse(code) }.to raise_error(Solargraph::Parser::SyntaxError)
   end
+
+  describe '#force_new_parser' do
+    after do
+      Solargraph::Parser.force_new_parser :current
+    end
+
+    it 'should handle :current' do
+      Solargraph::Parser.force_new_parser :current
+      expect(Solargraph::Parser.version).to eql(RUBY_VERSION.split('.')[..1].join.to_i)
+    end
+
+    it 'should fall back to using :current in case of bad input' do
+      Solargraph::Parser.force_new_parser 'not a version string'
+      expect(Solargraph::Parser.version).to eql(RUBY_VERSION.split('.')[..1].join.to_i)
+    end
+
+    it 'should use modern parser for supported versions' do
+      Solargraph::Parser.force_new_parser '3.4.4'
+      expect(Solargraph::Parser.version).to eql(34)
+      expect(Solargraph::Parser.parser).to be_a(Prism::Translation::Parser)
+    end
+
+    it 'should use legacy parser for when modern parser cannot be used' do
+      Solargraph::Parser.force_new_parser '2.7.4'
+      expect(Solargraph::Parser.version).to eql(27)
+      expect(Solargraph::Parser.parser).to be_a(Parser::Ruby27)
+    end
+  end
+
+  describe 'different versions' do
+    after do
+      Solargraph::Parser.force_new_parser :current
+    end
+
+    it 'fails to parser ruby 3 syntax when using ruby 2 parsing' do
+      Solargraph::Parser.force_new_parser('2.7')
+
+      expect(Solargraph::Parser.version).to eql(27)
+      expect { Solargraph::Parser.parse('def available? = !@internal.any?') }.to raise_error(Solargraph::Parser::SyntaxError)
+    end
+
+    it 'succeeds in parsing ruby 3 syntax when using ruby 3 parsing' do
+      Solargraph::Parser.force_new_parser('3.3')
+
+      expect(Solargraph::Parser.version).to eql(33)
+      node = Solargraph::Parser.parse('def available? = !@internal.any?', 'test.rb')
+      expect(Solargraph::Parser.is_ast_node?(node)).to be(true)
+    end
+  end
 end

spec/workspace_spec.rb

@@ -50,7 +50,7 @@
   end
 
   it "raises an exception for workspace size limits" do
-    config = double(:config, calculated: Array.new(Solargraph::Workspace::Config::MAX_FILES + 1), max_files: Solargraph::Workspace::Config::MAX_FILES)
+    config = double(:config, calculated: Array.new(Solargraph::Workspace::Config::MAX_FILES + 1), max_files: Solargraph::Workspace::Config::MAX_FILES, ruby_version: 'current')
 
     expect {
       Solargraph::Workspace.new('.', config)
@@ -62,7 +62,7 @@
     File.write(gemspec_file, '')
     calculated = Array.new(Solargraph::Workspace::Config::MAX_FILES + 1) { gemspec_file }
     # @todo Mock reveals tight coupling
-    config = double(:config, calculated: calculated, max_files: 0, allow?: true, require_paths: [], plugins: [])
+    config = double(:config, calculated: calculated, max_files: 0, allow?: true, require_paths: [], plugins: [], ruby_version: 'current')
     expect {
       Solargraph::Workspace.new('.', config)
     }.not_to raise_error
@@ -134,7 +134,7 @@
   end
 
   it 'rescues errors loading files into sources' do
-    config = double(:Config, directory: './path', calculated: ['./path/does_not_exist.rb'], max_files: 5000, require_paths: [], plugins: [])
+    config = double(:config, directory: './path', calculated: ['./path/does_not_exist.rb'], max_files: 5000, require_paths: [], plugins: [], ruby_version: 'current')
     expect {
       Solargraph::Workspace.new('./path', config)
     }.not_to raise_error