RuboCop: Modularity and AST Insights

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Support OSS community

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$POUFOUT **3VCZ-41"EEPO *1MVHJO4ZTUFN ***"45*OTJHIUT

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rubocop/rubocop#13792 *1MVHJO4ZTUFN

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50%0Ϋϥεਤʁ MJCSVCPDPQFYBNQMFSC require 'rubocop' require_relative 'rubocop/example' require_relative 'rubocop/example/version' require_relative 'rubocop/example/inject' RuboCop::Example::Inject.defaults! require_relative 'rubocop/cop/example_cops' #.rubocop.yml require: - rubocop-example Extension gem require 'rubocop-example' *UJTF ff FDUJWFMZFRVJWBMFOUUP require 'rubocop-example' User's configuration *OKFDUIBDL

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*OKFDUIBDLT1SPCMFNT w 50%0Ϋϥεਤʁ class RuboCop::Example::Inject def self.default! path = CONFIG_DEFAULT.to_s h = ConfigLoader.load_yaml_configuration(path) conf = Config.new(h, path).tap(&:make_excludes_absolute) puts "configuration from..." if ConfigLoader.debug? new_conf = ConfigLoader.merge_with_default(conf, path) ConfigLoader.instance_variable_set( :@default_configuration, new_conf ) end -BUFSBEEFECVH fi Y #SPLFOFODBQTVMBUJPO 3FEVOEBOUEFCVHMPHHJOH

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*OKFDUIBDLJT/05 BOPG fi DJBMXBZ⚠

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MJOU@SPMMFS A plugin specification for linters "Depend on Abstractions" Agile Software Development: Principles, Patterns, and Practices Robert C. Martin

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w 0MEQMVHJODPO fi HTZOUBY USJHHFSXBSOJOHT w /FXQMVHJODPO fi HTZOUBY TVQQSFTTUIFXBSOJOHT 6TFplugins*OTUFBE # .rubocop.yml require: rubocop-example # .rubocop.yml plugins: rubocop-example

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*OIFSJU-JOU3PMMFS1MVHJO require 'lint_roller' module RuboCop module Example class Plugin < LintRoller::Plugin def about def supported?(context) def rules(_context) end end end *OIFSJUGSPN-JOU3PMMFS1MVHJO Define a plugin class RuboCop::Example::Plugin

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$SFBUF-JOU3PMMFS"CPVU class Plugin < LintRoller::Plugin def about LintRoller::About.new( name: 'rubocop-example', version: Version::STRING, homepage: 'https://github.com/...', description: '...' ) end def supported?(context) def rules(_context) %F fi OFBCPVUNFUIPEUIBU SFUVSOTB-JOU3PMMFS"CPVUXJUI QMVHJONFUBEBUB3BJTFTBO FYDFQUJPOJGOPUEF fi OFE 1MVHJOOBNFVTFEJOUIF QMVHJOTTFDUJPOPGUIF VTFSTSVCPDPQZNM SFDPHOJ[FECZ3VCP$PQ

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%F fi OF1MVHJOTVQQPSUFE class Plugin < LintRoller::Plugin def about def supported?(context) context.engine == :rubocop end def rules(_context) "'", POMZ3VCP$PQTVQQPSUT MJOU@SPMMFSGPSOPX CVUPUIFSMJOUFST MJLF3VGPBSFBMTPCFJOHDPOTJEFSFE %FGBVMUJTUSVF

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$SFBUF-JOU3PMMFS3VMFT class Plugin < LintRoller::Plugin def about def supported?(context) def rules(_context) LintRoller::Rules.new( type: :path, config_format: :rubocop, value: "#{__dir__}/../../../config/default.yml" ) end end NOTE: There are no dependencies on RuboCop's API like those seen in the "Inject" hack %F fi OFSVMFTNFUIPEUIBUSFUVSOTB -JOU3PMMFS3VMFTXJUIUIFJOGP3VCP$PQ OFFETUPMPDBUFUIFQMVHJODPO fi H 3BJTFTBOFYDFQUJPOJGOPUEF fi OFE

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HFNTQFD ,FZUP"CTUSBDUJPO Gem::Specification.new do |spec| # snip spec.metadata = { 'default_lint_roller_plugin' => 'RuboCop::Example::Plugin' } spec.add_dependency('lint_roller', '~> 1.1') end 💡Setting default_lint_roller_plugin key allows RuboCop engine and user's .rubocop.yml to avoid needing to know the plugin's custom name. 4FUUIFQMVHJOOBNFJOUIFHFNTQFD TP3VCP$PQDBOEJTDPWFSJU

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3VCP$PQ1MVHJO module RuboCop module Plugin class << self def integrate_plugins(rubocop_config, plugins) plugins = Plugin::Loader.load(plugins) ConfigurationIntegrator. integrate_plugins_into_rubocop_config( rubocop_config, plugins ) plugins end end end *OUFSOBM"1*XIFSF3VCP$PQMPBETQMVHJOT BOENFSHFTDPO fi HT

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module RuboCop::Plugin class Loader def self.load(plugins) plugin_configs = normalize(plugins) plugin_configs.filter_map do |name, config| next unless plugin_config['enabled'] plugin_class = constantize_plugin_from(name, config) plugin_class.new(plugin_config) end end name = Gem.loaded_specs[plugin_name].metadata[ 'default_lint_roller_plugin' ] Kernel.const_get(name) Implementation Details 3VCP$PQ1MVHJO-PBEFS (FUTUIFQMVHJODPOTUGSPN QMVHJOTHFNTQFDNFUBEBUB

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3VCP$PQ1MVHJO$PO fi HVSBUJPO*OUFHSBUPS module RuboCop::Plugin class ConfigurationIntegrator def self.integrate_plugins_into_rubocop_config( rubocop_config, plugins ) default_config = ConfigLoader.default_configuration runner_context = create_context(rubocop_config) validate_plugins!(plugins, runner_context) # snip (Merging of configurations) end end &OHJOFDPMMBCPSBUFTXJUI QMVHJOGPSQSPDFTTJOH

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$SFBUF-JOU3PMMFS$POUFYU module RuboCop::Plugin class ConfigurationIntegrator def self.create_context(rubocop_config) LintRoller::Context.new( runner: :rubocop, runner_version: Version.version, engine: :rubocop, engine_version: Version.version, target_ruby_version: rubocop_config.target_ruby_version ) end end 3FUVSOTB-JOU3PMMFS$POUFYUXJUISVOUJNFJOGP MJLFUIFMJOUFSFOHJOFBOEBOBMZTJT3VCZWFSTJPO QBTTFEUPQMVHJOT

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7BMJEBUJPO module RuboCop::Plugin class ConfigurationIntegrator def self.validate_plugins!(plugins, runner_context) unsupported_plugins = plugins.reject { |plugin| plugin.supported?(runner_context) } return if unsupported_plugins.none? raise NotSupportedError, unsupported_plugins end end class Plugin < LintRoller::Plugin def supported?(context) context.engine == :rubocop end Plugin's Implementation

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rubocop/rubocop#13628 **3VCZ-41"EEPO GPS3VCP$PQ

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3VCP$PQTCVJMEJO-41 Built-in LSP Request (JSON-RPC) 3VCP$PQ 3VOOFS SVO DBMM SFRVFTU EFMFHBUF 3VCP$PQ$-* $PNNBOE -41 rubocop --lsp 3VCP$PQ-41 4FSWFS 1MVHJO &EJUPS*%& 3VCP$PQ-41 3PVUFT 3VCP$PQ-41 3VOUJNF P ff FOTFT GPSNBU XSJUF TUBSU IUUQTSVCZLBJHJPSHQSFTFOUBUJPOTLPJDIUNMEBZ

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3VCZ-413VCP$PQ"EEPO w 50%0Ϋϥεਤʁ module RubyLSP::RuboCop class Addon < RubyLSP::Addon def activate(global_state, message_queue) @runtime_adapter = RuntimeAdapter.new global_state.register_formatter( 'rubocop', @runtime_adapter ) # snip end def deactivate @runtime_adapter = nil end *OIFSJUGSPN3VCZ-41"EEPO *OUIFBDUJWBUFDBMMCBDLNFUIPEGSPN 3VCZ-41 SFHJTUFSBOBEBQUFSUP UIF3VCP$PQCVJMUJO-41SVOUJNF

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3VCZ-413VCP$PQ3VOUJNF"EBQUFS w 50%0Ϋϥεਤʁ module RubyLSP::RuboCop class RuntimeAdapter def initialize @runtime = RuboCop::LSP::Runtime.new(config) end def run_diagnostic(uri, document) @runtime.offenses(uri_to_path(uri), document.source, document.encoding) end def run_formatting(uri, document) @runtime.format(uri_to_path(uri), document.source, command: '...') end $SFBUFTUIF3VOUJNFDMBTTUPIBOEMFDBMMCBDLTGSPN3VCZ-41 %F fi OFTEFMFHBUJPOGSPNUIFSVO@EJBHOPTUJDDBMMCBDL %F fi OFTEFMFHBUJPOGSPNUIFSVO@GPSNBUUJOHDBMMCBDL

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#FGPSF3VCZ,BJHJ

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w 4UBSUJOHJO3VCP$PQ 1SJTNDBOCF VTFEBTBOPQUJPOBMCBDLFOE w *UVTFTPrism::Translation::Parser UPDPOWFSU1SJTNT"45UPUIFQBSTFS HFNJOUFSGBDF 3FVTJOH"45JO3VCZ-41 AllCops: ParserEngine: parser_prism # Ruby 3.3+ Syntax

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class Prism::Translation::Parser < ::Parser::Base def initialize(builder = Parser::Builder.new, parser: Prism) @parser = parser super(builder) end def tokenize(source_buffer, recover = false) # snip result = unwrap( @parser.parse_lex(source, **prism_options), offset_cache) # snip end SVCZQSJTN 5IFEFGBVMUQBSTFSDMBTTJT1SJTN JUDBOCFTXJUDIFE "OZSFDFJWFSUIBUSFTQPOETUPQBSTFS@MFYXPSLT

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SVCPDPQSVCPDPQBTU w 50%0Ϋϥεਤʁ module RuboCop::AST class PrismParsed # Internal API def initialized(prism_result) @prism_result = prism_result end def parse_lex(_source, **_prism_options) @prism_result end end end 💡An internal class for duck typing with parse_lex. 4UPSFUIFQBSTFESFTVMUGSPN1SJTN 3FUVSOUIFQBSTFESFTVMUGSPN1SJTNXJUIPVUQBSTJOH

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SVCPDPQSVCPDPQBTU w 50%0Ϋϥεਤʁ class RuboCop::AST::ProcessedSource def create_parser( ruby_version, parser_engine, prism_result ) # The parser_class is chosen by version and engine. parser_class = Prism::Translation::Parser34 ... prism_parsed = PrismParsed.new(prism_result) parser_instance = parser_class.new( builder, parser: prism_parsed ) ... end $SFBUFBDVTUPNQBSTFS VTJOHB1SJTNSFTVMU 3FQMBDFXJUIBQBSTFSJOUFSGBDFDMBTTUIBU SFVTFTUIFHJWFO1SJTNSFTVMU

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In the near future ***"45*OTJHIUT

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.PUJWBUJPO#BDLHSPVOE Two years earlier than expected :-)

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%FTJHOPGUIF1BSTFSHFN generate QBSTFZ 3VCZ1BSTFS QBSTFD QBSTFTP GPS3VCZ 3VCZ1BSTFS QBSTFD QBSTFTP GPS3VCZ $ lrama QBSTFZ read read generate ruby/ruby <> SVCZZ 3VCZ1BSTFS SVCZSC 3VCZ1BSTFS SVCZSC $ racc SVCZZ read read <> whitequark/parser *OIFSJUTGSPNParser::Base

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QBSTFS@QSJTNCZ%FGBVMUGPS3VCZ "OBMZTJTDPEFXJUI3VCP$PQ 3VOOJOH3VCP$PQXJUI3VCZ AllCops: # Use parser_prism parser by default TargetRubyVersion: 3.4 $ bundle exec rubocop Use the same parser in Ruby and RuboCop!

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*TUIFOFYUTUFQGPS 3VCP$PQUPTVQQPSU OBUJWF1SJTN"45🤔

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IUUQTXXXZPVUVCFDPNXBUDI W),@-G8E/3: On considering the potential of Lrama

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class Prism::Translation::Parser < ::Parser::Base def initialize(builder = Parser::Builder.new, parser: Prism) @parser = parser super(builder) end def tokenize(source_buffer, recover = false) # snip result = unwrap( @parser.parse_lex(source, **prism_options), offset_cache) # snip end SVCZQSJTN "HBJO 5IFEFGBVMUQBSTFSDMBTTJT1SJTN JUDBOCFTXJUDIFE "OZSFDFJWFSUIBUSFTQPOETUPQBSTFS@MFYXPSLT

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