Add a rubocop config

Author: kddnewton

.rubocop.yml

@@ -0,0 +1,85 @@
+inherit_from: config/rubocop.yml
+
+AllCops:
+  DisplayCopNames: true
+  DisplayStyleGuide: true
+  NewCops: enable
+  SuggestExtensions: false
+  TargetRubyVersion: 2.7
+  Exclude:
+  - '{bin,coverage,pkg,test/fixtures,vendor,tmp}/**/*'
+  - test.rb
+
+Layout/LineLength:
+  Max: 80
+  AllowedPatterns:
+  - '^\s*in '
+  - '^\s*location: Location'
+
+Lint/DuplicateBranch:
+  Enabled: false
+
+Lint/InterpolationCheck:
+  Enabled: false
+
+Lint/MissingSuper:
+  Enabled: false
+
+Metrics:
+  Enabled: false
+
+Naming/MethodName:
+  Enabled: false
+
+Naming/MethodParameterName:
+  Enabled: false
+
+Naming/RescuedExceptionsVariableName:
+  PreferredName: error
+
+Style/ExplicitBlockArgument:
+  Enabled: false
+
+Style/FormatString:
+  EnforcedStyle: percent
+
+Style/GuardClause:
+  Enabled: false
+
+Style/IdenticalConditionalBranches:
+  Enabled: false
+
+Style/KeywordParametersOrder:
+  Enabled: false
+
+Style/MutableConstant:
+  Enabled: false
+
+Style/NegatedIfElseCondition:
+  Enabled: false
+
+Style/NumericPredicate:
+  Enabled: false
+
+Style/ParallelAssignment:
+  Enabled: false
+
+Style/PerlBackrefs:
+  Enabled: false
+
+Style/SpecialGlobalVars:
+  Enabled: false
+
+###
+
+Lint/AssignmentInCondition:
+  Enabled: false
+
+Lint/UnusedMethodArgument:
+  Enabled: false
+
+Style/Documentation:
+  Enabled: false
+
+Style/StringLiterals:
+  Enabled: false

Gemfile

@@ -3,3 +3,5 @@
 source "https://rubygems.org"
 
 gemspec
+
+gem "rubocop"

Gemfile.lock

@@ -6,15 +6,35 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
+    ast (2.4.2)
     docile (1.4.0)
     minitest (5.15.0)
+    parallel (1.22.1)
+    parser (3.1.2.0)
+      ast (~> 2.4.1)
+    rainbow (3.1.1)
     rake (13.0.6)
+    regexp_parser (2.3.1)
+    rexml (3.2.5)
+    rubocop (1.28.2)
+      parallel (~> 1.10)
+      parser (>= 3.1.0.0)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml
+      rubocop-ast (>= 1.17.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.17.0)
+      parser (>= 3.1.1.0)
+    ruby-progressbar (1.11.0)
     simplecov (0.21.2)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
       simplecov_json_formatter (~> 0.1)
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
+    unicode-display_width (2.1.0)
 
 PLATFORMS
   arm64-darwin-21
@@ -27,6 +47,7 @@ DEPENDENCIES
   bundler
   minitest
   rake
+  rubocop
   simplecov
   syntax_tree!
 

config/rubocop.yml

@@ -0,0 +1,69 @@
+# Disabling all Layout/* rules, as they're unnecessary when the user is using
+# Syntax Tree to handle all of the formatting.
+Layout:
+  Enabled: false
+
+# Re-enable Layout/LineLength because certain cops that most projects use
+# (e.g. Style/IfUnlessModifier) require Layout/LineLength to be enabled.
+# By leaving it disabled, those rules will mis-fire.
+#
+# Users can always override these defaults in their own rubocop.yml files.
+# https://github.com/prettier/plugin-ruby/issues/825
+#
+# We're also explicitly allowing pattern matching to extend beyond the maximum
+# line length, since SyntaxTree prefers putting patterns on a single line.
+Layout/LineLength:
+  Enabled: true
+  AllowedPatterns:
+  - '^\s*in '
+
+Style/MultilineIfModifier:
+  Enabled: false
+
+# Syntax Tree will expand empty methods to put the end keyword on the subsequent
+# line to reduce git diff noise.
+Style/EmptyMethod:
+  EnforcedStyle: expanded
+
+# lambdas that are constructed with the lambda method call cannot be safely
+# turned into lambda literals without removing a method call.
+Style/Lambda:
+  Enabled: false
+
+# When method chains with multiple blocks are chained together, rubocop will let
+# them pass if they're using braces but not if they're using do and end
+# keywords. Because we will break individual blocks down to using keywords if
+# they are multiline, this conflicts with rubocop.
+Style/MultilineBlockChain:
+  Enabled: false
+
+# Syntax Tree by default uses double quotes, so changing the configuration here
+# to match that.
+Style/StringLiterals:
+  EnforcedStyle: double_quotes
+
+Style/StringLiteralsInInterpolation:
+  EnforcedStyle: double_quotes
+
+Style/QuotedSymbols:
+  EnforcedStyle: double_quotes
+
+# We let users have a little more freedom with symbol and words arrays. If the
+# user only has an individual item like ["value"] then we don't bother
+# converting it because it ends up being just noise.
+Style/SymbolArray:
+  Enabled: false
+
+Style/WordArray:
+  Enabled: false
+
+# We don't support trailing commas in Syntax Tree by default, so just turning
+# these off for now.
+Style/TrailingCommaInArguments:
+  Enabled: false
+
+Style/TrailingCommaInArrayLiteral:
+  Enabled: false
+
+Style/TrailingCommaInHashLiteral:
+  Enabled: false

lib/syntax_tree/cli.rb

@@ -242,7 +242,7 @@ def run(argv)
 
         # If we're not reading from stdin and the user didn't supply and
         # filepaths to be read, then we exit with the usage message.
-        if STDIN.tty? && arguments.empty?
+        if $stdin.tty? && arguments.empty?
           warn(HELP)
           return 1
         end
@@ -280,7 +280,7 @@ def run(argv)
           errored = true
         rescue Check::UnformattedError, Debug::NonIdempotentFormatError
           errored = true
-        rescue => error
+        rescue StandardError => error
           warn(error.message)
           warn(error.backtrace)
           errored = true
@@ -298,7 +298,7 @@ def run(argv)
       private
 
       def each_file(arguments)
-        if STDIN.tty?
+        if $stdin.tty?
           arguments.each do |pattern|
             Dir.glob(pattern).each do |filepath|
               next unless File.file?(filepath)
@@ -309,7 +309,7 @@ def each_file(arguments)
             end
           end
         else
-          yield HANDLERS[".rb"], :stdin, STDIN.read
+          yield HANDLERS[".rb"], :stdin, $stdin.read
         end
       end
 

lib/syntax_tree/language_server.rb

@@ -10,7 +10,7 @@ module SyntaxTree
   class LanguageServer
     attr_reader :input, :output
 
-    def initialize(input: STDIN, output: STDOUT)
+    def initialize(input: $stdin, output: $stdout)
       @input = input.binmode
       @output = output.binmode
     end
@@ -88,6 +88,8 @@ def inlay_hints(source)
         after: inlay_hints.after.map(&serialize)
       }
     rescue Parser::ParseError
+      # If there is a parse error, then we're not going to return any inlay
+      # hints for this source.
     end
 
     def write(value)

lib/syntax_tree/node.rb

@@ -761,7 +761,7 @@ def format(q)
               if part.is_a?(StringLiteral)
                 q.format(part.parts.first)
               else
-                q.text(part.value[1..-1])
+                q.text(part.value[1..])
               end
             end
           end
@@ -1190,7 +1190,7 @@ def deconstruct_keys(keys)
     end
 
     def format(q)
-      if value&.is_a?(HashLiteral)
+      if value.is_a?(HashLiteral)
         format_contents(q)
       else
         q.group { format_contents(q) }
@@ -2301,7 +2301,7 @@ def format(q)
 
       # First, walk down the chain until we get to the point where we're not
       # longer at a chainable node.
-      while true
+      loop do
         case children.last
         in Call[receiver: Call]
           children << children.last.receiver
@@ -3079,7 +3079,7 @@ def trailing?
     end
 
     def ignore?
-      value[1..-1].strip == "stree-ignore"
+      value[1..].strip == "stree-ignore"
     end
 
     def comments
@@ -3917,7 +3917,7 @@ def quotes(q)
         end
       elsif Quotes.locked?(self)
         if quote.start_with?(":")
-          [hash_key ? quote[1..-1] : quote, quote[1..-1]]
+          [hash_key ? quote[1..] : quote, quote[1..]]
         else
           [hash_key ? quote : ":#{quote}", quote]
         end
@@ -4967,7 +4967,7 @@ def format(q)
 
   # The list of nodes that represent patterns inside of pattern matching so that
   # when a pattern is being printed it knows if it's nested.
-  PATTERNS = [AryPtn, Binary, FndPtn, HshPtn, RAssign]
+  PATTERNS = [AryPtn, Binary, FndPtn, HshPtn, RAssign].freeze
 
   # Ident represents an identifier anywhere in code. It can represent a very
   # large number of things, depending on where it is in the syntax tree.
@@ -5587,7 +5587,7 @@ def format(q)
         # the values, then we're going to insert them every 3 characters
         # starting from the right.
         index = (value.length + 2) % 3
-        q.text("  #{value}"[index..-1].scan(/.../).join("_").strip)
+        q.text("  #{value}"[index..].scan(/.../).join("_").strip)
       else
         q.text(value)
       end
@@ -6475,7 +6475,7 @@ def skip_indent?
   # This approach maintains the nice conciseness of the inline version, while
   # keeping the correct semantic meaning.
   module Parentheses
-    NODES = [Args, Assign, Assoc, Binary, Call, Defined, MAssign, OpAssign]
+    NODES = [Args, Assign, Assoc, Binary, Call, Defined, MAssign, OpAssign].freeze
 
     def self.flat(q)
       return yield unless NODES.include?(q.parent.class)
@@ -6686,7 +6686,7 @@ def format(q)
 
       contents = -> do
         q.seplist(parts) { |part| q.format(part) }
-        q.format(rest) if rest && rest.is_a?(ExcessedComma)
+        q.format(rest) if rest&.is_a?(ExcessedComma)
       end
 
       if ![Def, Defs, DefEndless].include?(q.parent.class) || parts.empty?
@@ -7323,14 +7323,14 @@ def format(q)
           end
 
           q.text("}")
-          q.text(ending[1..-1])
+          q.text(ending[1..])
         end
       else
         q.group do
           q.text("/")
           q.format_each(parts)
           q.text("/")
-          q.text(ending[1..-1])
+          q.text(ending[1..])
         end
       end
     end