Cops

Bundler 7

• Bundler/DuplicatedGemChecks for duplicate gem entries in Gemfile.on-a0.46
• Bundler/DuplicatedGroupChecks for duplicate group entries in Gemfile.on-a1.56
• Bundler/GemCommentAdd a comment describing each gem.opt-in-a0.59
• Bundler/GemFilenameEnforces the filename for managing gems.on-a1.20
• Bundler/GemVersionRequires or forbids specifying gem versions.opt-in-a1.14
• Bundler/InsecureProtocolSourceThe source :gemcutter, :rubygems and :rubyforge are deprecated because HTTP requests are insecure. Please change your source to 'https://rubygems.org' if possible, or 'http://rubygems.org' if not.on-a0.50
• Bundler/OrderedGemsGems within groups in the Gemfile should be alphabetically sorted.on-a0.46

Gemspec 10

• Gemspec/AddRuntimeDependencyPrefer add_dependency over add_runtime_dependency.pending-a1.65
• Gemspec/AttributeAssignmentUse consistent style for Gemspec attributes assignment.pending-a1.77
• Gemspec/DependencyVersionRequires or forbids specifying gem dependency versions.opt-in-a1.29
• Gemspec/DeprecatedAttributeAssignmentChecks that deprecated attribute assignments are not set in a gemspec file.pending-a1.30
• Gemspec/DevelopmentDependenciesChecks that development dependencies are specified in Gemfile rather than gemspec.pending-a1.44
• Gemspec/DuplicatedAssignmentAn attribute assignment method calls should be listed only once in a gemspec.on-a0.52
• Gemspec/OrderedDependenciesDependencies in the gemspec should be alphabetically sorted.on-a0.51
• Gemspec/RequireMFAChecks that the gemspec has metadata to require Multi-Factor Authentication from RubyGems.pending-a1.23
• Gemspec/RequiredRubyVersionChecks that required_ruby_version of gemspec is specified and equal to TargetRubyVersion of .rubocop.yml.on-a0.52
• Gemspec/RubyVersionGlobalsUsageChecks usage of RUBY_VERSION in gemspec.on-a0.72

Layout 100

• Layout/AccessModifierIndentationChecks indentation of private/protected visibility modifiers.on-a0.49
• Layout/ArgumentAlignmentAlign the arguments of a method call if they span more than one line.on-a0.68
• Layout/ArrayAlignmentAlign the elements of an array literal if they span more than one line.on-a0.49
• Layout/AssignmentIndentationChecks the indentation of the first line of the right-hand-side of a multi-line assignment.on-a0.49
• Layout/BeginEndAlignmentAlign ends corresponding to begins correctly.on-a0.91
• Layout/BlockAlignmentAlign block ends correctly.on-a0.53
• Layout/BlockEndNewlinePut end statement of multiline block on its own line.on-a0.49
• Layout/CaseIndentationChecks how the when and in clauses of a case expression are indented.on-a0.49
• Layout/ClassStructureEnforces a configured order of definitions within a class body.opt-in-A0.52
• Layout/ClosingHeredocIndentationChecks the indentation of here document closings.on-a0.57
• Layout/ClosingParenthesisIndentationChecks the indentation of hanging closing parentheses.on-a0.49
• Layout/CommentIndentationChecks the indentation of comments.on-a0.49
• Layout/ConditionPositionChecks for condition placed in a confusing position relative to the keyword.on-a0.53
• Layout/DefEndAlignmentAlign ends corresponding to defs correctly.on-a0.53
• Layout/DotPositionChecks the position of the dot in multi-line method calls.on-a0.49
• Layout/ElseAlignmentAlign elses and elsifs correctly.on-a0.49
• Layout/EmptyCommentChecks empty comment.on-a0.53
• Layout/EmptyLineAfterGuardClauseAdd empty line after guard clause.on-a0.56
• Layout/EmptyLineAfterMagicCommentAdd an empty line after magic comments to separate them from code.on-a0.49
• Layout/EmptyLineAfterMultilineConditionEnforces empty line after multiline condition.opt-in-a0.90
• Layout/EmptyLineBetweenDefsUse empty lines between class/module/method defs.on-a0.49
• Layout/EmptyLinesDon't use several empty lines in a row.on-a0.49
• Layout/EmptyLinesAfterModuleInclusionKeeps track of empty lines after module inclusion methods.pending-a1.79
• Layout/EmptyLinesAroundAccessModifierKeep blank lines around access modifiers.on-a0.49
• Layout/EmptyLinesAroundArgumentsKeeps track of empty lines around method arguments.on-a0.52
• Layout/EmptyLinesAroundAttributeAccessorKeep blank lines around attribute accessors.on-a0.83
• Layout/EmptyLinesAroundBeginBodyKeeps track of empty lines around begin-end bodies.on-a0.49
• Layout/EmptyLinesAroundBlockBodyKeeps track of empty lines around block bodies.on-a0.49
• Layout/EmptyLinesAroundClassBodyKeeps track of empty lines around class bodies.on-a0.49
• Layout/EmptyLinesAroundExceptionHandlingKeywordsKeeps track of empty lines around exception handling keywords.on-a0.49
• Layout/EmptyLinesAroundMethodBodyKeeps track of empty lines around method bodies.on-a0.49
• Layout/EmptyLinesAroundModuleBodyKeeps track of empty lines around module bodies.on-a0.49
• Layout/EndAlignmentAlign ends correctly.on-a0.53
• Layout/EndOfLineUse Unix-style line endings.on-a0.49
• Layout/ExtraSpacingDo not use unnecessary spacing.on-a0.49
• Layout/FirstArgumentIndentationChecks the indentation of the first argument in a method call.on-a0.68
• Layout/FirstArrayElementIndentationChecks the indentation of the first element in an array literal.on-a0.68
• Layout/FirstArrayElementLineBreakChecks for a line break before the first element in a multi-line array.opt-in-a0.49
• Layout/FirstHashElementIndentationChecks the indentation of the first key in a hash literal.on-a0.68
• Layout/FirstHashElementLineBreakChecks for a line break before the first element in a multi-line hash.opt-in-a0.49
• Layout/FirstMethodArgumentLineBreakChecks for a line break before the first argument in a multi-line method call.opt-in-a0.49
• Layout/FirstMethodParameterLineBreakChecks for a line break before the first parameter in a multi-line method parameter definition.opt-in-a0.49
• Layout/FirstParameterIndentationChecks the indentation of the first parameter in a method definition.on-a0.49
• Layout/HashAlignmentAlign the elements of a hash literal if they span more than one line.on-a0.49
• Layout/HeredocArgumentClosingParenthesisChecks for the placement of the closing parenthesis in a method call that passes a HEREDOC string as an argument.opt-in-a0.68
• Layout/HeredocIndentationChecks the indentation of the here document bodies.on-a0.49
• Layout/IndentationConsistencyKeep indentation straight.on-a0.49
• Layout/IndentationStyleConsistent indentation either with tabs only or spaces only.on-a0.49
• Layout/IndentationWidthUse 2 spaces for indentation.on-a0.49
• Layout/InitialIndentationChecks the indentation of the first non-blank non-comment line in a file.on-a0.49
• Layout/LeadingCommentSpaceComments should start with a space.on-a0.49
• Layout/LeadingEmptyLinesChecks for unnecessary blank lines at the beginning of a file.on-a0.57
• Layout/LineContinuationLeadingSpaceUse trailing spaces instead of leading spaces in strings broken over multiple lines (by a backslash).pending-a1.31
• Layout/LineContinuationSpacingChecks the spacing in front of backslash in line continuations.pending-a1.31
• Layout/LineEndStringConcatenationIndentationChecks the indentation of the next line after a line that ends with a string literal and a backslash.pending-a1.18
• Layout/LineLengthChecks that line length does not exceed the configured limit.on-a0.25
• Layout/MultilineArrayBraceLayoutChecks that the closing brace in an array literal is either on the same line as the last array element, or a new line.on-a0.49
• Layout/MultilineArrayLineBreaksChecks that each item in a multi-line array literal starts on a separate line.opt-in-a0.67
• Layout/MultilineAssignmentLayoutChecks for a newline after the assignment operator in multi-line assignments.opt-in-a0.49
• Layout/MultilineBlockLayoutEnsures newlines after multiline block do statements.on-a0.49
• Layout/MultilineHashBraceLayoutChecks that the closing brace in a hash literal is either on the same line as the last hash element, or a new line.on-a0.49
• Layout/MultilineHashKeyLineBreaksChecks that each item in a multi-line hash literal starts on a separate line.opt-in-a0.67
• Layout/MultilineMethodArgumentLineBreaksChecks that each argument in a multi-line method call starts on a separate line.opt-in-a0.67
• Layout/MultilineMethodCallBraceLayoutChecks that the closing brace in a method call is either on the same line as the last method argument, or a new line.on-a0.49
• Layout/MultilineMethodCallIndentationChecks indentation of method calls with the dot operator that span more than one line.on-a0.49
• Layout/MultilineMethodDefinitionBraceLayoutChecks that the closing brace in a method definition is either on the same line as the last method parameter, or a new line.on-a0.49
• Layout/MultilineMethodParameterLineBreaksChecks that each parameter in a multi-line method definition starts on a separate line.opt-in-a1.32
• Layout/MultilineOperationIndentationChecks indentation of binary operations that span more than one line.on-a0.49
• Layout/ParameterAlignmentAlign the parameters of a method definition if they span more than one line.on-a0.49
• Layout/RedundantLineBreakDo not break up an expression into multiple lines when it fits on a single line.opt-in-a1.13
• Layout/RescueEnsureAlignmentAlign rescues and ensures correctly.on-a0.49
• Layout/SingleLineBlockChainPut method call on a separate line if chained to a single line block.opt-in-a1.14
• Layout/SpaceAfterColonUse spaces after colons.on-a0.49
• Layout/SpaceAfterCommaUse spaces after commas.on-a0.49
• Layout/SpaceAfterMethodNameDo not put a space between a method name and the opening parenthesis in a method definition.on-a0.49
• Layout/SpaceAfterNotTracks redundant space after the ! operator.on-a0.49
• Layout/SpaceAfterSemicolonUse spaces after semicolons.on-a0.49
• Layout/SpaceAroundBlockParametersChecks the spacing inside and after block parameters pipes.on-a0.49
• Layout/SpaceAroundEqualsInParameterDefaultChecks that the equals signs in parameter default assignments have or don't have surrounding space depending on configuration.on-a0.49
• Layout/SpaceAroundKeywordUse a space around keywords if appropriate.on-a0.49
• Layout/SpaceAroundMethodCallOperatorChecks method call operators to not have spaces around them.on-a0.82
• Layout/SpaceAroundOperatorsUse a single space around operators.on-a0.49
• Layout/SpaceBeforeBlockBracesChecks that the left block brace has or doesn't have space before it.on-a0.49
• Layout/SpaceBeforeBracketsChecks for receiver with a space before the opening brackets.pending-a1.7
• Layout/SpaceBeforeCommaNo spaces before commas.on-a0.49
• Layout/SpaceBeforeCommentChecks for missing space between code and a comment on the same line.on-a0.49
• Layout/SpaceBeforeFirstArgChecks that exactly one space is used between a method name and the first argument for method calls without parentheses.on-a0.49
• Layout/SpaceBeforeSemicolonNo spaces before semicolons.on-a0.49
• Layout/SpaceInLambdaLiteralChecks for spaces in lambda literals.on-a0.49
• Layout/SpaceInsideArrayLiteralBracketsChecks the spacing inside array literal brackets.on-a0.52
• Layout/SpaceInsideArrayPercentLiteralNo unnecessary additional spaces between elements in %i/%w literals.on-a0.49
• Layout/SpaceInsideBlockBracesChecks that block braces have or don't have surrounding space. For blocks taking parameters, checks that the left brace has or doesn't have trailing space.on-a0.49
• Layout/SpaceInsideHashLiteralBracesUse spaces inside hash literal braces - or don't.on-a0.49
• Layout/SpaceInsideParensNo spaces after ( or before ).on-a0.49
• Layout/SpaceInsidePercentLiteralDelimitersNo unnecessary spaces inside delimiters of %i/%w/%x literals.on-a0.49
• Layout/SpaceInsideRangeLiteralNo spaces inside range literals.on-a0.49
• Layout/SpaceInsideReferenceBracketsChecks the spacing inside referential brackets.on-a0.52
• Layout/SpaceInsideStringInterpolationChecks for padding/surrounding spaces inside string interpolation.on-a0.49
• Layout/TrailingEmptyLinesChecks trailing blank lines and final newline.on-a0.49
• Layout/TrailingWhitespaceAvoid trailing whitespace.on-a0.49

Lint 160

• Lint/AmbiguousAssignmentChecks for mistyped shorthand assignments.pending-a1.7
• Lint/AmbiguousBlockAssociationChecks for ambiguous block association with method when param passed without parentheses.on-a0.48
• Lint/AmbiguousOperatorChecks for ambiguous operators in the first argument of a method invocation without parentheses.on-a0.17
• Lint/AmbiguousOperatorPrecedenceChecks for expressions containing multiple binary operations with ambiguous precedence.pending-a1.21
• Lint/AmbiguousRangeChecks for ranges with ambiguous boundaries.pending-A1.19
• Lint/AmbiguousRegexpLiteralChecks for ambiguous regexp literals in the first argument of a method invocation without parentheses.on-a0.17
• Lint/ArgumentMismatchChecks for calls that pass the wrong number of positional arguments to a method, using the project index.pending-a1.90
• Lint/ArrayLiteralInRegexpChecks for an array literal interpolated inside a regexp.pending-A1.71
• Lint/AssignmentInConditionDon't use assignment in conditions.on-A0.9
• Lint/BigDecimalNewBigDecimal.new() is deprecated. Use BigDecimal() instead.on-a0.53
• Lint/BinaryOperatorWithIdenticalOperandsChecks for places where binary operator has identical operands.on-a0.89
• Lint/BooleanSymbolChecks for :true and :false symbols.on-A0.50
• Lint/CircularArgumentReferenceDefault values in optional keyword arguments and optional ordinal arguments should not refer back to the name of the argument.on-a0.33
• Lint/ConstantDefinitionInBlockDo not define constants within a block.on-a0.91
• Lint/ConstantOverwrittenInRescueChecks for overwriting an exception with an exception result by use rescue =>.pending-a1.31
• Lint/ConstantReassignmentChecks for constant reassignments.pending-a1.70
• Lint/ConstantResolutionChecks that constants are fully qualified with ::.opt-in-a0.86
• Lint/CopDirectiveSyntaxChecks that # rubocop: directives are strictly formatted.on-a1.72
• Lint/DataDefineOverrideDisallow overriding the Data built-in methods via Data.define.pending-a1.85
• Lint/DebuggerChecks for debugger calls.on-a0.14
• Lint/DeprecatedClassMethodsChecks for deprecated class method calls.on-a0.19
• Lint/DeprecatedConstantsChecks for deprecated constants.pending-a1.8
• Lint/DeprecatedOpenSSLConstantDon't use algorithm constants for OpenSSL::Cipher and OpenSSL::Digest.on-a0.84
• Lint/DeprecatedReferenceChecks for references to methods and constants documented as deprecated with a YARD @deprecated tag. Requires AllCops/UseProjectIndex to be enabled.pending-a1.89
• Lint/DisjunctiveAssignmentInConstructorIn constructor, plain assignment is preferred over disjunctive.on-A0.62
• Lint/DuplicateBranchChecks that there are no repeated bodies within if/unless, case-when and rescue constructs.pending-a1.3
• Lint/DuplicateCaseConditionDo not repeat values in case conditionals.on-a0.45
• Lint/DuplicateElsifConditionDo not repeat conditions used in if elsif.on-a0.88
• Lint/DuplicateHashKeyChecks for duplicate keys in hash literals.on-a0.34
• Lint/DuplicateMagicCommentChecks for duplicated magic comments.pending-a1.37
• Lint/DuplicateMatchPatternDo not repeat patterns in in keywords.pending-a1.50
• Lint/DuplicateMethodsChecks for duplicate method definitions.on-a0.29
• Lint/DuplicateRegexpCharacterClassElementChecks for duplicate elements in Regexp character classes.pending-a1.1
• Lint/DuplicateRequireChecks for duplicate requires and require_relatives.on-A0.90
• Lint/DuplicateRescueExceptionChecks that there are no repeated exceptions used in rescue expressions.on-a0.89
• Lint/DuplicateSetElementChecks for duplicate elements in Set.pending-a1.67
• Lint/EachWithObjectArgumentChecks for immutable argument given to each_with_object.on-a0.31
• Lint/ElseLayoutChecks for odd code arrangement in an else block.on-a0.17
• Lint/EmptyBlockChecks for blocks without a body.pending-a1.1
• Lint/EmptyClassChecks for classes and metaclasses without a body.pending-a1.3
• Lint/EmptyConditionalBodyChecks for the presence of if, elsif and unless branches without a body.on-a0.89
• Lint/EmptyEnsureChecks for empty ensure block.on-a0.10
• Lint/EmptyExpressionChecks for empty expressions.on-a0.45
• Lint/EmptyFileEnforces that Ruby source files are not empty.on-a0.90
• Lint/EmptyInPatternChecks for the presence of in pattern branches without a body.pending-a1.16
• Lint/EmptyInterpolationChecks for empty string interpolation.on-a0.20
• Lint/EmptyWhenChecks for when branches with empty bodies.on-a0.45
• Lint/EnsureReturnDo not use return in an ensure block.on-a0.9
• Lint/ErbNewArgumentsUse :trim_mode and :eoutvar keyword arguments to ERB.new.on-a0.56
• Lint/FlipFlopChecks for flip-flops.on-a0.16
• Lint/FloatComparisonChecks for the presence of precise comparison of floating point numbers.on-a0.89
• Lint/FloatOutOfRangeCatches floating-point literals too large or small for Ruby to represent.on-a0.36
• Lint/FormatParameterMismatchChecks for a mismatch between the format fields and the arguments to format/sprintf/%.on-a0.33
• Lint/HashCompareByIdentityPrefer using Hash#compare_by_identity than using object_id for keys.on-a0.93
• Lint/HashNewWithKeywordArgumentsAsDefaultChecks for the deprecated use of keyword arguments for hash default in Hash.new.pending-a1.69
• Lint/HeredocMethodCallPositionChecks for the ordering of a method call where the receiver of the call is a HEREDOC.opt-in-a0.68
• Lint/IdentityComparisonPrefer equal? over == when comparing object_id.on-a0.91
• Lint/ImplicitStringConcatenationChecks for adjacent string literals on the same line, which could better be represented as a single string literal.on-a0.36
• Lint/IncompatibleIoSelectWithFiberSchedulerChecks for IO.select that is incompatible with Fiber Scheduler.pending-A1.21
• Lint/IneffectiveAccessModifierChecks for attempts to use private or protected to set the visibility of a class method, which does not work.on-a0.36
• Lint/InheritExceptionAvoid inheriting from the Exception class.on-A0.41
• Lint/InterpolationCheckChecks for interpolation in a single quoted string.on-A0.50
• Lint/ItWithoutArgumentsInBlockChecks uses of it calls without arguments in block.pending-a1.59
• Lint/LambdaWithoutLiteralBlockChecks uses of lambda without a literal block.pending-a1.8
• Lint/LiteralAsConditionChecks of literals used in conditions.on-a0.51
• Lint/LiteralAssignmentInConditionChecks for literal assignments in the conditions.pending-a1.58
• Lint/LiteralInInterpolationChecks for literals used in interpolation.on-a0.19
• Lint/LoopUse Kernel#loop with break rather than begin/end/until or begin/end/while for post-loop tests.on-A0.9
• Lint/MisplacedMagicCommentChecks for magic comments placed where Ruby silently ignores them.pending-A1.91
• Lint/MissingCopEnableDirectiveChecks for a # rubocop:enable after # rubocop:disable.on-a0.52
• Lint/MissingSuperChecks for the presence of constructors and lifecycle callbacks without calls to super.on-a0.89
• Lint/MixedCaseRangeChecks for mixed-case character ranges since they include likely unintended characters.pending-A1.53
• Lint/MixedRegexpCaptureTypesDo not mix named captures and numbered captures in a Regexp literal.on-a0.85
• Lint/MultipleComparisonUse && operator to compare multiple values.on-a0.47
• Lint/NameTypoChecks for probable typos in constant and method names, using the project index.pending-a1.89
• Lint/NestedMethodDefinitionDo not use nested method definitions.on-a0.32
• Lint/NestedPercentLiteralChecks for nested percent literals.on-a0.52
• Lint/NextWithoutAccumulatorDo not omit the accumulator when calling next in a reduce/inject block.on-a0.36
• Lint/NoReturnInBeginEndBlocksDo not return inside begin..end blocks in assignment contexts.pending-a1.2
• Lint/NonAtomicFileOperationChecks for non-atomic file operations.pending-A1.31
• Lint/NonDeterministicRequireOrderAlways sort arrays returned by Dir.glob when requiring files.on-A0.78
• Lint/NonLocalExitFromIteratorDo not use return in iterator to cause non-local exit.on-a0.30
• Lint/NumberConversionChecks unsafe usage of number conversion methods.opt-in-A0.53
• Lint/NumberedParameterAssignmentChecks for uses of numbered parameter assignment.pending-a1.9
• Lint/NumericOperationWithConstantResultChecks for numeric operations with constant results.pending-A1.69
• Lint/OrAssignmentToConstantChecks unintended or-assignment to constant.pending-A1.9
• Lint/OrderedMagicCommentsChecks the proper ordering of magic comments and whether a magic comment is not placed before a shebang.on-A0.53
• Lint/OutOfRangeRegexpRefChecks for out of range reference for Regexp because it always returns nil.on-a0.89
• Lint/ParenthesesAsGroupedExpressionChecks for method calls with a space before the opening parenthesis.on-a0.12
• Lint/PercentStringArrayChecks for unwanted commas and quotes in %w/%W literals.on-A0.41
• Lint/PercentSymbolArrayChecks for unwanted commas and colons in %i/%I literals.on-a0.41
• Lint/RaiseExceptionChecks for raise or fail statements which are raising Exception class.on-A0.81
• Lint/RandOneChecks for rand(1) calls. Such calls always return 0 and most likely a mistake.on-a0.36
• Lint/RedundantCopDisableDirectiveChecks for rubocop:disable comments that can be removed. Note: this cop is not disabled when disabling all cops. It must be explicitly disabled.on-a0.76
• Lint/RedundantCopEnableDirectiveChecks for rubocop:enable comments that can be removed.on-a0.76
• Lint/RedundantDirGlobSortChecks for redundant sort method to Dir.glob and Dir[].pending-A1.8
• Lint/RedundantRegexpQuantifiersChecks for redundant quantifiers in Regexps.pending-a1.53
• Lint/RedundantRequireStatementChecks for unnecessary require statement.on-a0.76
• Lint/RedundantSafeNavigationChecks for redundant safe navigation calls.on-A0.93
• Lint/RedundantSplatExpansionChecks for splat unnecessarily being called on literals.on-a0.76
• Lint/RedundantStringCoercionChecks for Object#to_s usage in string interpolation.on-a0.19
• Lint/RedundantTypeConversionChecks for redundantly converting a literal to the same type.pending-a1.72
• Lint/RedundantWithIndexChecks for redundant with_index.on-a0.50
• Lint/RedundantWithObjectChecks for redundant with_object.on-A0.51
• Lint/RefinementImportMethodsUse Refinement#import_methods when using include or prepend in refine block.pending-A1.27
• Lint/RegexpAsConditionDo not use regexp literal as a condition. The regexp literal matches $_ implicitly.on-a0.51
• Lint/RequireParenthesesUse parentheses in the method call to avoid confusion about precedence.on-a0.18
• Lint/RequireRangeParenthesesChecks that a range literal is enclosed in parentheses when the end of the range is at a line break.pending-a1.32
• Lint/RequireRelativeSelfPathChecks for uses a file requiring itself with require_relative.pending-a1.22
• Lint/RescueExceptionAvoid rescuing the Exception class.on-a0.9
• Lint/RescueTypeAvoid rescuing from non constants that could result in a TypeError.on-a0.49
• Lint/ReturnInVoidContextChecks for return in void context.on-a0.50
• Lint/SafeNavigationChainDo not chain ordinary method call after safe navigation operator.on-A0.47
• Lint/SafeNavigationConsistencyCheck to make sure that if safe navigation is used in an && or || condition, consistent and appropriate safe navigation, without excess or deficiency, is used for all method calls on the same object.on-A0.55
• Lint/SafeNavigationWithEmptyAvoid foo&.empty? in conditionals.on-a0.62
• Lint/ScriptPermissionGrant script file execute permission.on-a0.49
• Lint/SelfAssignmentChecks for self-assignments.on-a0.89
• Lint/SendWithMixinArgumentChecks for send method when using mixin.on-a0.75
• Lint/ShadowedArgumentAvoid reassigning arguments before they were used.on-a0.52
• Lint/ShadowedExceptionAvoid rescuing a higher level exception before a lower level exception.on-a0.41
• Lint/ShadowingOuterLocalVariableDo not use the same name as outer local variable for block arguments or block local variables.opt-in-a0.9
• Lint/SharedMutableDefaultChecks for mutable literals used as default arguments during Hash initialization.pending-a1.70
• Lint/StructNewOverrideDisallow overriding the Struct built-in methods via Struct.new.on-a0.81
• Lint/SuperArgumentMismatchChecks for super calls that pass the wrong number of positional arguments to the overridden implementation, using the project index.pending-a1.90
• Lint/SuppressedExceptionDon't suppress exceptions.on-a0.9
• Lint/SuppressedExceptionInNumberConversionChecks for cases where exceptions unrelated to the numeric constructors may be unintentionally swallowed.pending-A1.72
• Lint/SymbolConversionChecks for unnecessary symbol conversions.pending-a1.9
• Lint/SyntaxChecks for syntax errors.on-a0.9
• Lint/ToEnumArgumentsEnsures that to_enum/enum_for, called for the current method, has correct arguments.pending-a1.1
• Lint/ToJSONEnsure #to_json includes an optional argument.on-a0.66
• Lint/TopLevelReturnWithArgumentDetects top level return statements with argument.on-a0.89
• Lint/TrailingCommaInAttributeDeclarationChecks for trailing commas in attribute declarations.on-a0.90
• Lint/TripleQuotesChecks for useless triple quote constructs.pending-a1.9
• Lint/UnderscorePrefixedVariableNameDo not use prefix _ for a variable that is used.on-a0.21
• Lint/UnescapedBracketInRegexpChecks for unescaped literal ] in Regexp.pending-a1.68
• Lint/UnexpectedBlockArityLooks for blocks that have fewer arguments that the calling method expects.pending-a1.5
• Lint/UnifiedIntegerUse Integer instead of Fixnum or Bignum.on-a0.43
• Lint/UnmodifiedReduceAccumulatorChecks for reduce or inject blocks that do not update the accumulator each iteration.pending-a1.1
• Lint/UnreachableCodeChecks for unreachable code.on-a0.9
• Lint/UnreachableLoopChecks for loops that will have at most one iteration.on-a0.89
• Lint/UnreachablePatternBranchChecks for unreachable in pattern branches after an unconditional catch-all pattern.pending-a1.85
• Lint/UnusedBlockArgumentChecks for unused block arguments.on-a0.21
• Lint/UnusedMethodArgumentChecks for unused method arguments.on-a0.21
• Lint/UnusedPrivateMethodChecks for private instance methods that are not referenced anywhere in the project. Requires AllCops/UseProjectIndex to be enabled.opt-in-a1.89
• Lint/UriEscapeUnescapeURI.escape method is obsolete and should not be used. Instead, use CGI.escape, URI.encode_www_form or URI.encode_www_form_component depending on your specific use case. Also URI.unescape method is obsolete and should not be used. Instead, use CGI.unescape, URI.decode_www_form or URI.decode_www_form_component depending on your specific use case.on-a0.50
• Lint/UriRegexpUse URI::DEFAULT_PARSER.make_regexp instead of URI.regexp.on-a0.50
• Lint/UselessAccessModifierChecks for useless access modifiers.on-a0.20
• Lint/UselessAssignmentChecks for useless assignment to a local variable.on-a0.11
• Lint/UselessConstantScopingChecks for useless constant scoping.pending-a1.72
• Lint/UselessDefaultValueArgumentChecks for usage of fetch or Array.new with default value argument and block.pending-A1.76
• Lint/UselessDefinedChecks for calls to defined? with strings and symbols. The result of such a call will always be truthy.pending-a1.69
• Lint/UselessElseWithoutRescueChecks for useless else in begin..end without rescue.on-a0.17
• Lint/UselessMethodDefinitionChecks for useless method definitions.on-A0.90
• Lint/UselessNumericOperationChecks for useless numeric operations.pending-a1.66
• Lint/UselessOrChecks for useless OR expressions.pending-A1.76
• Lint/UselessRescueChecks for useless rescues.pending-a1.43
• Lint/UselessRuby2KeywordsFinds unnecessary uses of ruby2_keywords.pending-a1.23
• Lint/UselessSetterCallChecks for useless setter call to a local variable.on-A0.13
• Lint/UselessTimesChecks for useless Integer#times calls.on-A0.91
• Lint/VoidChecks for operators, literals, lambdas, and procs used in void context.on-a0.9

Metrics 10

• Metrics/AbcSizeChecks that the ABC size of methods is not higher than the configured maximum.on-a0.27
• Metrics/BlockLengthAvoid long blocks with many lines.on-a0.44
• Metrics/BlockNestingAvoid excessive block nesting.on-a0.25
• Metrics/ClassLengthAvoid classes longer than 100 lines of code.on-a0.25
• Metrics/CollectionLiteralLengthChecks for Array or Hash literals with many entries.pending-a1.47
• Metrics/CyclomaticComplexityChecks that the cyclomatic complexity of methods is not higher than the configured maximum.on-a0.25
• Metrics/MethodLengthAvoid methods longer than 10 lines of code.on-a0.25
• Metrics/ModuleLengthAvoid modules longer than 100 lines of code.on-a0.31
• Metrics/ParameterListsAvoid parameter lists longer than three or four parameters.on-a0.25
• Metrics/PerceivedComplexityChecks that the perceived complexity of methods is not higher than the configured maximum.on-a0.25

Migration 1

• Migration/DepartmentNameChecks that cop names in rubocop:disable (etc.) comments are given with a department name.on-a0.75

Naming 19

• Naming/AccessorMethodNameChecks the naming of accessor methods for get_/set_.on-a0.50
• Naming/AsciiIdentifiersUse only ascii symbols in identifiers and constants.on-a0.50
• Naming/BinaryOperatorParameterNameChecks that the sole parameter of binary operator methods is named other.on-a0.50
• Naming/BlockForwardingUse anonymous block forwarding.pending-a1.24
• Naming/BlockParameterNameChecks for block parameter names that contain capital letters, end in numbers, or do not meet a minimal length.on-a0.53
• Naming/ClassAndModuleCamelCaseUse CamelCase for classes and modules.on-a0.50
• Naming/ConstantNameConstants should use SCREAMING_SNAKE_CASE.on-a0.50
• Naming/FileNameUse snake_case for source file names.on-a0.50
• Naming/HeredocDelimiterCaseUse configured case for heredoc delimiters.on-a0.50
• Naming/HeredocDelimiterNamingUse descriptive heredoc delimiters.on-a0.50
• Naming/InclusiveLanguageRecommend the use of inclusive language instead of problematic terms.opt-in-a1.18
• Naming/MemoizedInstanceVariableNameMemoized method name should match memo instance variable name.on-A0.53
• Naming/MethodNameUse the configured style when naming methods.on-a0.50
• Naming/MethodParameterNameChecks for method parameter names that contain capital letters, end in numbers, or do not meet a minimal length.on-a0.53
• Naming/PredicateMethodChecks that predicate methods end with ? and non-predicate methods do not.pending-a1.76
• Naming/PredicatePrefixChecks that predicate method names end with a question mark and do not start with a forbidden prefix.on-a0.50
• Naming/RescuedExceptionsVariableNameUse consistent rescued exceptions variables naming.on-a0.67
• Naming/VariableNameUse the configured style when naming variables.on-a0.50
• Naming/VariableNumberUse the configured style when numbering symbols, methods and variables.on-a0.50

Security 7

• Security/CompoundHashChecks for hash implementations that combine values manually instead of delegating to Array#hash.pending-a1.28
• Security/EvalChecks for the use of Kernel#eval and Binding#eval with dynamic arguments.on-a0.47
• Security/IoMethodsChecks for the first argument to IO.read, IO.binread, IO.write, IO.binwrite, IO.foreach, and IO.readlines.pending-A1.22
• Security/JSONLoadPrefer usage of JSON.parse over JSON.load due to potential security issues. See reference for more information.on-A0.43
• Security/MarshalLoadAvoid using of Marshal.load or Marshal.restore due to potential security issues. See reference for more information.on-a0.47
• Security/OpenChecks for the use of Kernel#open and URI.open with dynamic data.on-a0.53
• Security/YAMLLoadPrefer usage of YAML.safe_load over YAML.load due to potential security issues. See reference for more information.on-A0.47

Style 299

• Style/AccessModifierDeclarationsChecks style of how access modifiers are used.on-A0.57
• Style/AccessorGroupingChecks for grouping of accessors in class and module bodies.on-a0.87
• Style/AliasUse alias instead of alias_method.on-a0.9
• Style/AmbiguousEndlessMethodDefinitionChecks for endless methods inside operators of lower precedence.pending-a1.68
• Style/AndOrUse &&/|| instead of and/or.on-A0.9
• Style/ArgumentsForwardingUse arguments forwarding.pending-a1.1
• Style/ArrayCoercionUse Array() instead of explicit Array check or [*var], when dealing with a variable you want to treat as an Array, but you're not certain it's an array.opt-in-A0.88
• Style/ArrayFirstLastUse arr.first and arr.last instead of arr[0] and arr[-1].opt-in-A1.58
• Style/ArrayIntersectUse array1.intersect?(array2) instead of (array1 & array2).any?.pending-A1.40
• Style/ArrayIntersectWithSingleElementUse include?(element) instead of intersect?([element]).pending-A1.81
• Style/ArrayJoinUse Array#join instead of Array#*.on-a0.20
• Style/AsciiCommentsUse only ascii symbols in comments.opt-in-a0.9
• Style/AttrChecks for uses of Module#attr.on-a0.9
• Style/AutoResourceCleanupSuggests the usage of an auto resource cleanup version of a method (if available).opt-in-a0.30
• Style/BarePercentLiteralsChecks if usage of %() or %Q() matches configuration.on-a0.25
• Style/BeginBlockAvoid the use of BEGIN blocks.on-a0.9
• Style/BisectedAttrAccessorChecks for places where attr_reader and attr_writer for the same method can be combined into single attr_accessor.on-a0.87
• Style/BitwisePredicatePrefer bitwise predicate methods over direct comparison operations.pending-A1.68
• Style/BlockCommentsDo not use block comments.on-a0.9
• Style/BlockDelimitersAvoid using {...} for multi-line blocks (multiline chaining is always ugly). Prefer {...} over do...end for single-line blocks.on-a0.30
• Style/CaseEqualityAvoid explicit use of the case equality operator (===).on-a0.9
• Style/CaseLikeIfIdentifies places where if-elsif constructions can be replaced with case-when.on-A0.88
• Style/CharacterLiteralChecks for uses of character literals.on-a0.9
• Style/ClassAndModuleChildrenChecks style of children classes and modules.on-A0.19
• Style/ClassCheckEnforces consistent use of Object#is_a? or Object#kind_of?.on-a0.24
• Style/ClassEqualityComparisonEnforces the use of Object#instance_of? instead of class comparison for equality.on-A0.93
• Style/ClassMethodsUse self when defining module/class methods.on-a0.9
• Style/ClassMethodsDefinitionsEnforces using def self.method_name or class << self to define class methods.opt-in-a0.89
• Style/ClassVarsAvoid the use of class variables.on-a0.13
• Style/CollectionCompactUse {Array,Hash}#{compact,compact!} instead of custom logic to reject nils.pending-A1.2
• Style/CollectionMethodsEnforces the use of consistent method names from the Enumerable module.opt-in-A0.9
• Style/CollectionQueryingPrefer Enumerable predicate methods over expressions with count.pending-A1.77
• Style/ColonMethodCallDo not use :: for method call.on-a0.9
• Style/ColonMethodDefinitionDo not use :: for defining class methods.on-a0.52
• Style/CombinableDefinedChecks successive defined? calls that can be combined into a single call.pending-a1.68
• Style/CombinableLoopsChecks for places where multiple consecutive loops over the same data can be combined into a single loop.on-A0.90
• Style/CommandLiteralUse `` or %x around command literals.on-a0.30
• Style/CommentAnnotationChecks formatting of special comments (TODO, FIXME, OPTIMIZE, HACK, REVIEW, NOTE).on-a0.10
• Style/CommentedKeywordDo not place comments on the same line as certain keywords.on-A0.51
• Style/ComparableBetweenEnforces the use of Comparable#between? instead of logical comparison.pending-A1.74
• Style/ComparableClampEnforces the use of Comparable#clamp instead of comparison by minimum and maximum.pending-a1.44
• Style/ConcatArrayLiteralsEnforces the use of Array#push(item) instead of Array#concat([item]) to avoid redundant array literals.pending-A1.41
• Style/ConditionalAssignmentUse the return value of if and case statements for assignment to a variable and variable comparison instead of assigning that variable inside of each branch.on-a0.36
• Style/ConstantVisibilityCheck that class- and module constants have visibility declarations.opt-in-a0.66
• Style/CopyrightInclude a copyright notice in each file before any code.opt-in-a0.30
• Style/DataInheritanceChecks for inheritance from Data.define.pending-A1.49
• Style/DateTimeUse Time over DateTime.opt-in-A0.51
• Style/DefWithParenthesesUse def with parentheses when there are arguments.on-a0.9
• Style/DigChainUse dig with multiple parameters instead of chaining multiple calls.pending-A1.69
• Style/DirUse the __dir__ method to retrieve the canonicalized absolute path to the current file.on-a0.50
• Style/DirEmptyPrefer to use Dir.empty?('path/to/dir') when checking if a directory is empty.pending-a1.48
• Style/DirectiveScopeChecks for directive scopes that can be expressed with the tighter disable-next form.pending-A1.90
• Style/DisableCopsWithinSourceCodeDirectiveForbids disabling/enabling cops within source code.opt-in-a0.82
• Style/DocumentDynamicEvalDefinitionWhen using class_eval (or other eval) with string interpolation, add a comment block showing its appearance if interpolated.pending-a1.1
• Style/DocumentationDocument classes and non-namespace modules.on-a0.9
• Style/DocumentationMethodChecks for missing documentation comment for public methods.opt-in-a0.43
• Style/DoubleNegationChecks for uses of double negation (!!).on-A0.19
• Style/EachForSimpleLoopUse Integer#times for a simple loop which iterates a fixed number of times.on-a0.41
• Style/EachWithObjectPrefer each_with_object over inject or reduce.on-a0.22
• Style/EmptyBlockParameterOmit pipes for empty block parameters.on-a0.52
• Style/EmptyCaseConditionAvoid empty condition in case statements.on-a0.40
• Style/EmptyClassDefinitionEnforces consistent style for empty class definitions.pending-a1.84
• Style/EmptyElseAvoid empty else-clauses.on-a0.28
• Style/EmptyHeredocChecks for using empty heredoc to reduce redundancy.pending-a1.32
• Style/EmptyLambdaParameterOmit parens for empty lambda parameters.on-a0.52
• Style/EmptyLiteralPrefer literals to Array.new/Hash.new/String.new.on-a0.9
• Style/EmptyMethodChecks the formatting of empty method definitions.on-a0.46
• Style/EmptyStringInsideInterpolationChecks for empty strings being assigned inside string interpolation.pending-a1.76
• Style/EncodingUse UTF-8 as the source file encoding.on-a0.9
• Style/EndBlockAvoid the use of END blocks.on-a0.9
• Style/EndlessMethodAvoid the use of multi-lined endless method definitions.pending-a1.8
• Style/EnvHomeChecks for consistent usage of ENV['HOME'].pending-A1.29
• Style/EvalWithLocationPass __FILE__ and __LINE__ to eval method, as they are used by backtraces.on-a0.52
• Style/EvenOddFavor the use of Integer#even? && Integer#odd?.on-a0.12
• Style/ExactRegexpMatchChecks for exact regexp match inside Regexp literals.pending-a1.51
• Style/ExpandPathArgumentsUse expand_path(__dir__) instead of expand_path('..', __FILE__).on-a0.53
• Style/ExplicitBlockArgumentConsider using explicit block argument to avoid writing block literal that just passes its arguments to another block.on-a0.89
• Style/ExponentialNotationEnforces consistency in the use of exponential (scientific) notation.on-a0.82
• Style/FetchEnvVarSuggests ENV.fetch for the replacement of ENV[].pending-a1.28
• Style/FileEmptyPrefer to use File.empty?('path/to/file') when checking if a file is empty.pending-A1.48
• Style/FileNullUse File::NULL instead of hardcoding "dev/null".pending-A1.69
• Style/FileOpenChecks for File.open without a block, which can leak file descriptors.pending-a1.85
• Style/FileReadFavor File.(bin)read convenience methods.pending-a1.24
• Style/FileTouchFavor FileUtils.touch for touching files.pending-A1.69
• Style/FileWriteFavor File.(bin)write convenience methods.pending-a1.24
• Style/FloatDivisionFor performing float division, coerce one side only.on-A0.72
• Style/ForChecks use of for or each in multiline loops.on-A0.13
• Style/FormatStringEnforce the use of Kernel#sprintf, Kernel#format or String#%.on-a0.19
• Style/FormatStringTokenUse a consistent style for format string tokens.on-a0.49
• Style/FrozenStringLiteralCommentAdd the frozen_string_literal comment to the top of files to help transition to frozen string literals by default.on-A0.36
• Style/GlobalStdStreamEnforces the use of $stdout/$stderr/$stdin instead of STDOUT/STDERR/STDIN.on-A0.89
• Style/GlobalVarsDo not introduce global variables.on-a0.13
• Style/GuardClauseChecks for conditionals that can be replaced with guard clauses.on-a0.20
• Style/HashAsLastArrayItemChecks for presence or absence of braces around hash literal as a last array item depending on configuration.on-a0.88
• Style/HashConversionAvoid Hash[] in favor of ary.to_h or literal hashes.pending-A1.10
• Style/HashEachMethodsUse Hash#each_key and Hash#each_value.on-A0.80
• Style/HashExceptChecks for usages of Hash#reject, Hash#select, and Hash#filter methods that can be replaced with Hash#except method.pending-A1.7
• Style/HashFetchChainUse Hash#dig instead of chained fetch calls.pending-A1.75
• Style/HashLikeCaseChecks for places where case-when represents a simple 1:1 mapping and can be replaced with a hash lookup.on-a0.88
• Style/HashLookupMethodEnforces the use of either Hash#[] or Hash#fetch for hash lookup.opt-in-A1.84
• Style/HashSliceChecks for usages of Hash#reject, Hash#select, and Hash#filter methods that can be replaced with Hash#slice method.pending-A1.71
• Style/HashSyntaxPrefer Ruby 1.9 hash syntax { a: 1, b: 2 } over 1.8 syntax { :a => 1, :b => 2 }.on-a0.9
• Style/HashTransformKeysPrefer transform_keys over each_with_object, map, or to_h.on-A0.80
• Style/HashTransformValuesPrefer transform_values over each_with_object, map, or to_h.on-A0.80
• Style/IdenticalConditionalBranchesChecks that conditional statements do not have an identical line at the end of each branch, which can validly be moved out of the conditional.on-A0.36
• Style/IfInsideElseFinds if nodes inside else, which can be converted to elsif.on-a0.36
• Style/IfUnlessModifierFavor modifier if/unless usage when you have a single-line body.on-a0.9
• Style/IfUnlessModifierOfIfUnlessAvoid modifier if/unless usage on conditionals.on-a0.39
• Style/IfWithBooleanLiteralBranchesChecks for redundant if with boolean literal branches.pending-A1.9
• Style/IfWithSemicolonDo not use if x; .... Use the ternary operator instead.on-a0.9
• Style/ImplicitRuntimeErrorUse raise or fail with an explicit exception class and message, rather than just a message.opt-in-a0.41
• Style/InPatternThenChecks for in; uses in case expressions.pending-a1.16
• Style/InfiniteLoopUse Kernel#loop for infinite loops. This cop is unsafe if the body may raise a StopIteration exception.on-A0.26
• Style/InlineCommentAvoid trailing inline comments.opt-in-a0.23
• Style/InverseMethodsUse the inverse method instead of !.method if an inverse method is defined.on-A0.48
• Style/InvertibleUnlessConditionFavor if with inverted condition over unless.opt-in-A1.44
• Style/IpAddressesDon't include literal IP addresses in code.opt-in-a0.58
• Style/ItAssignmentChecks for local variables and method parameters named it.pending-a1.70
• Style/ItBlockParameterChecks for blocks with one argument where it block parameter can be used.pending-a1.75
• Style/KeywordArgumentsMergingWhen passing an existing hash as keyword arguments, provide additional arguments directly rather than using merge.pending-a1.68
• Style/KeywordParametersOrderEnforces that optional keyword parameters are placed at the end of the parameters list.on-a0.90
• Style/LambdaUse the new lambda literal syntax for single-line blocks.on-a0.9
• Style/LambdaCallUse lambda.call(...) instead of lambda.(...).on-a0.13
• Style/LineEndConcatenationUse \ instead of + or << to concatenate two string literals at line end.on-A0.18
• Style/MagicCommentFormatUse a consistent style for magic comments.pending-a1.35
• Style/MapCompactWithConditionalBlockPrefer select or reject over map { ... }.compact.pending-A1.30
• Style/MapIntoArrayChecks for usages of each with <<, push, or append which can be replaced by map.pending-A1.63
• Style/MapJoinChecks for redundant map(&:to_s) before join.pending-A1.85
• Style/MapToHashPrefer to_h with a block over map.to_h.pending-A1.24
• Style/MapToSetPrefer to_set with a block over map.to_set.pending-A1.42
• Style/MethodCallWithArgsParenthesesUse parentheses for method calls with arguments.opt-in-a0.47
• Style/MethodCallWithoutArgsParenthesesDo not use parentheses for method calls with no arguments.on-a0.47
• Style/MethodCalledOnDoEndBlockAvoid chaining a method call on a do...end block.opt-in-a0.14
• Style/MethodDefParenthesesChecks if the method definitions have or don't have parentheses.on-a0.16
• Style/MinMaxUse Enumerable#minmax instead of Enumerable#min and Enumerable#max in conjunction.on-a0.50
• Style/MinMaxComparisonEnforces the use of max or min instead of comparison for greater or less.pending-A1.42
• Style/MissingElseRequire if/case expressions to have an else branches. If enabled, it is recommended that Style/UnlessElse and Style/EmptyElse be enabled. This will conflict with Style/EmptyElse if Style/EmptyElse is configured to style "both".opt-in-a0.30
• Style/MissingRespondToMissingChecks if method_missing is implemented without implementing respond_to_missing.on-a0.56
• Style/MixinGroupingChecks for grouping of mixins in class and module bodies.on-a0.48
• Style/MixinUsageChecks that include, extend and prepend exists at the top level.on-a0.51
• Style/ModuleFunctionChecks for usage of extend self in modules.on-A0.11
• Style/ModuleMemberExistenceCheckChecks for usage of Module methods returning arrays that can be replaced with equivalent predicates.pending-a1.82
• Style/MultilineBlockChainAvoid multi-line chains of blocks.on-a0.13
• Style/MultilineIfModifierChecks for uses of if/unless modifiers with multiline bodies.on-a0.45
• Style/MultilineIfThenDo not use then for multi-line if/unless.on-a0.9
• Style/MultilineInPatternThenDo not use then for multi-line in statement.pending-a1.16
• Style/MultilineMemoizationWrap multiline memoizations in a begin and end block.on-a0.44
• Style/MultilineMethodSignatureAvoid multi-line method signatures.opt-in-a0.59
• Style/MultilineTernaryOperatorAvoid multi-line ?: (the ternary operator); use if/unless instead.on-a0.9
• Style/MultilineWhenThenDo not use then for multi-line when statement.on-a0.73
• Style/MultipleComparisonAvoid comparing a variable with multiple items in a conditional, use Array#include? instead.on-a0.49
• Style/MutableConstantDo not assign mutable objects to constants.on-A0.34
• Style/NegatedIfFavor unless over if for negative conditions (or control flow or).on-a0.20
• Style/NegatedIfElseConditionChecks for uses of if-else and ternary operators with a negated condition which can be simplified by inverting condition and swapping branches.pending-a1.2
• Style/NegatedUnlessFavor if over unless for negative conditions.on-a0.69
• Style/NegatedWhileFavor until over while for negative conditions.on-a0.20
• Style/NegativeArrayIndexUse negative array indices instead of calculating array length minus a value. Also handles range patterns with length calculations. Recognizes preserving methods and their combinations, allowing safe replacement when the receiver matches.pending-a1.84
• Style/NestedFileDirnameChecks for nested File.dirname.pending-a1.26
• Style/NestedModifierAvoid using nested modifiers.on-a0.35
• Style/NestedParenthesizedCallsParenthesize method calls which are nested inside the argument list of another parenthesized method call.on-a0.36
• Style/NestedTernaryOperatorUse one expression per branch in a ternary operator.on-a0.9
• Style/NextUse next to skip iteration instead of a condition at the end.on-a0.22
• Style/NilComparisonPrefer x.nil? to x == nil.on-a0.12
• Style/NilLambdaPrefer -> {} to -> { nil }.pending-a1.3
• Style/NonNilCheckChecks for redundant nil checks.on-a0.20
• Style/NotUse ! instead of not.on-a0.9
• Style/NumberedParametersRestrict the usage of numbered parameters.pending-a1.22
• Style/NumberedParametersLimitAvoid excessive numbered params in a single block.pending-a1.22
• Style/NumericLiteralPrefixUse smallcase prefixes for numeric literals.on-a0.41
• Style/NumericLiteralsAdd underscores to large numeric literals to improve their readability.on-a0.9
• Style/NumericPredicateChecks for the use of predicate- or comparison methods for numeric comparisons.on-A0.42
• Style/ObjectThenEnforces the use of consistent method names Object#yield_self or Object#then.pending-a1.28
• Style/OneClassPerFileChecks that each source file defines at most one top-level class or module.pending-a1.85
• Style/OneLineConditionalFavor the ternary operator (?:) or multi-line constructs over single-line if/then/else/end constructs.on-a0.9
• Style/OpenStructUseAvoid using OpenStruct. As of Ruby 3.0, use is officially discouraged due to performance, version compatibility, and potential security issues.pending-a1.23
• Style/OperatorMethodCallChecks for redundant dot before operator method call.pending-a1.37
• Style/OptionHashDon't use option hashes when you can use keyword arguments.opt-in-a0.33
• Style/OptionalArgumentsChecks for optional arguments that do not appear at the end of the argument list.on-a0.33
• Style/OptionalBooleanParameterUse keyword arguments when defining method with boolean argument.on-a0.89
• Style/OrAssignmentRecommend usage of double pipe equals (||=) where applicable.on-a0.50
• Style/ParallelAssignmentCheck for simple usages of parallel assignment. It will only warn when the number of variables matches on both sides of the assignment.on-a0.32
• Style/ParenthesesAroundConditionDon't use parentheses around the condition of an if/unless/while.on-a0.9
• Style/PartitionInsteadOfDoubleSelectChecks for consecutive select/filter/find_all and reject calls on the same receiver with the same block body.pending-A1.85
• Style/PercentLiteralDelimitersUse %-literal delimiters consistently.on-a0.19
• Style/PercentQLiteralsChecks if uses of %Q/%q match the configured preference.on-a0.25
• Style/PerlBackrefsAvoid Perl-style regex back references.on-a0.13
• Style/PredicateWithKindPrefer any?(Klass) to any? { |x| x.is_a?(Klass) }.pending-A1.85
• Style/PreferredHashMethodsChecks use of has_key? and has_value? Hash methods.on-A0.41
• Style/ProcUse proc instead of Proc.new.on-a0.9
• Style/QuotedSymbolsUse a consistent style for quoted symbols.pending-a1.16
• Style/RaiseArgsChecks the arguments passed to raise/fail.on-A0.14
• Style/RandomWithOffsetPrefer to use ranges when generating random numbers instead of integers with offsets.on-a0.52
• Style/ReduceToHashUse to_h { ... } instead of each_with_object, inject, or reduce to build a hash.pending-A1.85
• Style/RedundantArgumentChecks for a redundant argument passed to certain methods.pending-A1.4
• Style/RedundantArrayConstructorChecks for the instantiation of array using redundant Array constructor.pending-a1.52
• Style/RedundantArrayFlattenChecks for redundant calls of Array#flatten.pending-A1.76
• Style/RedundantAssignmentChecks for redundant assignment before returning.on-a0.87
• Style/RedundantBeginDon't use begin blocks when they are not needed.on-a0.10
• Style/RedundantCapitalWChecks for %W when interpolation is not needed.on-a0.76
• Style/RedundantConditionChecks for unnecessary conditional expressions.on-a0.76
• Style/RedundantConditionalDon't return true/false from a conditional.on-a0.50
• Style/RedundantConstantBaseAvoid redundant :: prefix on constant.pending-a1.40
• Style/RedundantCurrentDirectoryInPathChecks for a redundant current directory in a path given to require_relative.pending-a1.53
• Style/RedundantDoubleSplatHashBracesChecks for redundant uses of double splat hash braces.pending-a1.41
• Style/RedundantEachChecks for redundant each.pending-A1.38
• Style/RedundantExceptionChecks for an obsolete RuntimeException argument in raise/fail.on-a0.14
• Style/RedundantFetchBlockUse fetch(key, value) instead of fetch(key) { value } when value has Numeric, Rational, Complex, Symbol or String type, false, true, nil or is a constant.on-A0.86
• Style/RedundantFileExtensionInRequireChecks for the presence of superfluous .rb extension in the filename provided to require and require_relative.on-a0.88
• Style/RedundantFilterChainIdentifies usages of any?, empty?, none? or one? predicate methods chained to select/filter/find_all and change them to use predicate method instead.pending-A1.52
• Style/RedundantFormatChecks for usages of Kernel#format or Kernel#sprintf with only a single argument.pending-A1.72
• Style/RedundantFreezeChecks usages of Object#freeze on immutable objects.on-a0.34
• Style/RedundantHeredocDelimiterQuotesChecks for redundant heredoc delimiter quotes.pending-a1.45
• Style/RedundantInitializeChecks for redundant initialize methods.pending-A1.27
• Style/RedundantInterpolationChecks for strings that are just an interpolated expression.on-A0.76
• Style/RedundantInterpolationUnfreezeChecks for redundant unfreezing of interpolated strings.pending-a1.66
• Style/RedundantLineContinuationChecks for redundant line continuation.pending-a1.49
• Style/RedundantMinMaxByIdentifies places where max_by/min_by can be replaced by max/min.pending-a1.85
• Style/RedundantParenthesesChecks for parentheses that seem not to serve any purpose.on-a0.36
• Style/RedundantPercentQChecks for %q/%Q when single quotes or double quotes would do.on-a0.76
• Style/RedundantRegexpArgumentIdentifies places where argument can be replaced from a deterministic regexp to a string.pending-a1.53
• Style/RedundantRegexpCharacterClassChecks for unnecessary single-element Regexp character classes.on-a0.85
• Style/RedundantRegexpConstructorChecks for the instantiation of regexp using redundant Regexp.new or Regexp.compile.pending-a1.52
• Style/RedundantRegexpEscapeChecks for redundant escapes in Regexps.on-a0.85
• Style/RedundantReturnDon't use return where it's not required.on-a0.10
• Style/RedundantSelfDon't use self where it's not needed.on-a0.10
• Style/RedundantSelfAssignmentChecks for places where redundant assignments are made for in place modification methods.on-A0.90
• Style/RedundantSelfAssignmentBranchChecks for places where conditional branch makes redundant self-assignment.pending-a1.19
• Style/RedundantSortUse min instead of sort.first, max_by instead of sort_by...last, etc.on-A0.76
• Style/RedundantSortByUse sort instead of sort_by { |x| x }.on-a0.36
• Style/RedundantStringEscapeChecks for redundant escapes in string literals.pending-a1.37
• Style/RedundantStructKeywordInitChecks for redundant keyword_init option for Struct.new.opt-in-A1.85
• Style/RegexpLiteralUse / or %r around regular expressions.on-a0.9
• Style/RequireOrderSort require and require_relative in alphabetical order.opt-in-A1.40
• Style/RescueModifierAvoid using rescue in its modifier form.on-a0.9
• Style/RescueStandardErrorAvoid rescuing without specifying an error class.on-a0.52
• Style/ReturnNilUse return instead of return nil.opt-in-a0.50
• Style/ReturnNilInPredicateMethodDefinitionChecks if uses of return or return nil in predicate method definition.pending-A1.53
• Style/ReverseFindUse array.rfind instead of array.reverse.find.pending-A1.84
• Style/SafeNavigationTransforms usages of a method call safeguarded by a check for the existence of the object to safe navigation (&.). Autocorrection is unsafe as it assumes the object will be nil or truthy, but never false.on-A0.43
• Style/SafeNavigationChainLengthEnforces safe navigation chains length to not exceed the configured maximum.pending-a1.68
• Style/SampleUse sample instead of shuffle.first, shuffle.last, and shuffle[Integer].on-a0.30
• Style/SelectByKindPrefer grep/grep_v to select/reject/find/detect with a kind check.pending-A1.85
• Style/SelectByRangePrefer grep/grep_v to select/reject/find/detect with a range check.pending-A1.85
• Style/SelectByRegexpPrefer grep/grep_v to select/reject/find/detect with a regexp match.pending-A1.22
• Style/SelfAssignmentChecks for places where self-assignment shorthand should have been used.on-a0.19
• Style/SemicolonDon't use semicolons to terminate expressions.on-a0.9
• Style/SendPrefer Object#__send__ or Object#public_send to send, as send may overlap with existing methods.opt-in-a0.33
• Style/SendWithLiteralMethodNameDetects the use of the public_send method with a static method name argument.pending-A1.64
• Style/SignalExceptionChecks for proper usage of fail and raise.on-a0.11
• Style/SingleArgumentDigAvoid using single argument dig method.on-A0.89
• Style/SingleLineBlockParamsEnforces the names of some block params.opt-in-a0.16
• Style/SingleLineDoEndBlockChecks for single-line do...end blocks.pending-a1.57
• Style/SingleLineMethodsAvoid single-line methods.on-a0.9
• Style/SlicingWithRangeChecks array slicing is done with redundant, endless, and beginless ranges when suitable.on-A0.83
• Style/SoleNestedConditionalFinds sole nested conditional nodes which can be merged into outer conditional node.on-a0.89
• Style/SpecialGlobalVarsAvoid Perl-style global variables.on-A0.13
• Style/StabbyLambdaParenthesesChecks for the usage of parentheses around stabby lambda arguments.on-a0.35
• Style/StaticClassPrefer modules to classes with only class methods.opt-in-A1.3
• Style/StderrPutsUse warn instead of $stderr.puts.on-a0.51
• Style/StringCharsChecks for uses of String#split with empty string or regexp literal argument.pending-A1.12
• Style/StringConcatenationChecks for places where string concatenation can be replaced with string interpolation.on-A0.89
• Style/StringHashKeysPrefer symbols instead of strings as hash keys.opt-in-A0.52
• Style/StringLiteralsChecks if uses of quotes match the configured preference.on-a0.9
• Style/StringLiteralsInInterpolationChecks if uses of quotes inside expressions in interpolated strings match the configured preference.on-a0.27
• Style/StringMethodsChecks if configured preferred methods are used over non-preferred.opt-in-a0.34
• Style/StripUse strip instead of lstrip.rstrip.on-a0.36
• Style/StructInheritanceChecks for inheritance from Struct.new.on-A0.29
• Style/SuperArgumentsCall super without arguments and parentheses when the signature is identical.pending-a1.64
• Style/SuperWithArgsParenthesesUse parentheses for super with arguments.pending-a1.58
• Style/SwapValuesEnforces the use of shorthand-style swapping of 2 variables.pending-A1.1
• Style/SymbolArrayUse %i or %I for arrays of symbols.on-a0.9
• Style/SymbolLiteralUse plain symbols instead of string symbols when possible.on-a0.30
• Style/SymbolProcUse symbols as procs instead of blocks when possible.on-A0.26
• Style/TallyMethodPrefer Enumerable#tally over manual counting patterns.pending-A1.85
• Style/TernaryParenthesesChecks for use of parentheses around ternary conditions.on-a0.42
• Style/TimeNowPrefer Time.now over Time.new when retrieving the current system time.pending-a1.90
• Style/TopLevelMethodDefinitionLooks for top-level method definitions.opt-in-a1.15
• Style/TrailingBodyOnClassClass body goes below class statement.on-a0.53
• Style/TrailingBodyOnMethodDefinitionChecks for trailing code after the method definition.on-a0.52
• Style/TrailingBodyOnModuleChecks for trailing code after the module definition.on-a0.53
• Style/TrailingCommaInArgumentsChecks for trailing comma in argument lists.on-a0.36
• Style/TrailingCommaInArrayLiteralChecks for trailing comma in array literals.on-a0.53
• Style/TrailingCommaInBlockArgsChecks for useless trailing commas in block arguments.opt-in-A0.81
• Style/TrailingCommaInHashLiteralChecks for trailing comma in hash literals.on-a0.53
• Style/TrailingMethodEndStatementChecks for trailing end statement on line of method body.on-a0.52
• Style/TrailingUnderscoreVariableChecks for the usage of unneeded trailing underscores at the end of parallel variable assignment.on-a0.31
• Style/TrivialAccessorsPrefer attr_* methods to trivial readers/writers.on-a0.9
• Style/UnlessElseDo not use unless with else. Rewrite these with the positive case first.on-a0.9
• Style/UnlessLogicalOperatorsChecks for use of logical operators in an unless condition.opt-in-a1.11
• Style/UnpackFirstChecks for accessing the first element of String#unpack instead of using unpack1.on-a0.54
• Style/VariableInterpolationDon't interpolate global, instance and class variables directly in strings.on-a0.9
• Style/WhenThenUse when x then ... for one-line cases.on-a0.9
• Style/WhileUntilDoChecks for redundant do after while or until.on-a0.9
• Style/WhileUntilModifierFavor modifier while/until usage when you have a single-line body.on-a0.9
• Style/WordArrayUse %w or %W for arrays of words.on-a0.9
• Style/YAMLFileReadChecks for the use of YAML.load, YAML.safe_load, and YAML.parse with File.read argument.pending-a1.53
• Style/YodaConditionForbid or enforce yoda conditions.on-A0.49
• Style/YodaExpressionForbid the use of yoda expressions.opt-in-A1.42
• Style/ZeroLengthPredicateUse #empty? when testing for objects of length 0.on-A0.37

Capybara 6 rubocop-capybara 3.0.0

• Capybara/AmbiguousClickSpecify the exact target to click on.opt-in-a2.22
• Capybara/AssertStyleChecks for usage of deprecated assert style method.on-a2.23
• Capybara/FindAllFirstEnforces use of first instead of all with first or [0].on-A2.22
• Capybara/RedundantWithinFindChecks for redundant within find(...) calls.on-a2.20
• Capybara/SpecificActionsChecks for there is a more specific actions offered by Capybara.on-a2.14
• Capybara/SpecificFindersChecks if there is a more specific finder offered by Capybara.on-a2.13

Capybara/RSpec 9 rubocop-capybara 3.0.0

• Capybara/RSpec/CurrentPathExpectationChecks that no expectations are set on Capybara's current_path.on-a1.18
• Capybara/RSpec/HaveContentChecks for usage of have_content and have_no_content.on-a2.23
• Capybara/RSpec/HaveSelectorUse have_css or have_xpath instead of have_selector.on-a2.19
• Capybara/RSpec/MatchStyleChecks for usage of deprecated style methods in RSpec matchers.on-a2.23
• Capybara/RSpec/NegationMatcherEnforces use of have_no_* or not_to for negated expectations.on-a2.14
• Capybara/RSpec/NegationMatcherAfterVisitDo not allow negative matchers to be used immediately after visit.on-a2.22
• Capybara/RSpec/PredicateMatcherPrefer using predicate matcher over using predicate method directly.on-a2.19
• Capybara/RSpec/SpecificMatcherChecks for there is a more specific matcher offered by Capybara.on-a2.12
• Capybara/RSpec/VisibilityMatcherChecks for boolean visibility in Capybara finders.on-a1.39

FactoryBot 11 rubocop-factory_bot 2.28.0

• FactoryBot/AssociationStyleUse a consistent style to define associations.pending-A2.23
• FactoryBot/AttributeDefinedStaticallyAlways declare attribute values as blocks.on-a1.28
• FactoryBot/ConsistentParenthesesStyleUse a consistent style for parentheses in factory_bot calls.pending-a2.14
• FactoryBot/CreateListChecks for create_list usage.on-A1.25
• FactoryBot/ExcessiveCreateListCheck for excessive model creation in a list.pending-a2.25
• FactoryBot/FactoryAssociationWithStrategyUse definition in factory association instead of hard coding a strategy.pending-a2.23
• FactoryBot/FactoryClassNameUse string value when setting the class attribute explicitly.on-a1.37
• FactoryBot/FactoryNameStyleChecks for name style for argument of FactoryBot::Syntax::Methods.pending-a2.16
• FactoryBot/IdSequenceDo not create a FactoryBot sequence for an id column.pending-a2.24
• FactoryBot/RedundantFactoryOptionChecks for redundant factory option.pending-a2.23
• FactoryBot/SyntaxMethodsUse shorthands from FactoryBot::Syntax::Methods in your specs.pending-A2.7

Minitest 55 rubocop-minitest 0.41.0

• Minitest/AssertEmptyThis cop enforces the test to use assert_empty instead of using assert(object.empty?).on-a0.2
• Minitest/AssertEmptyLiteralThis cop enforces the test to use assert_empty instead of using assert_equal([], object).opt-in-a0.5
• Minitest/AssertEqualThis cop enforces the test to use assert_equal instead of using assert(expected == actual).on-a0.4
• Minitest/AssertInDeltaThis cop enforces the test to use assert_in_delta instead of using assert_equal to compare floats.pending-a0.10
• Minitest/AssertIncludesThis cop enforces the test to use assert_includes instead of using assert(collection.include?(object)).on-a0.2
• Minitest/AssertInstanceOfThis cop enforces the test to use assert_instance_of(Class, object) over assert(object.instance_of?(Class))on-a0.4
• Minitest/AssertKindOfThis cop enforces the test to use assert_kind_of(Class, object) over assert(object.kind_of?(Class))pending-a0.10
• Minitest/AssertMatchThis cop enforces the test to use assert_match instead of using assert(matcher.match(object)).on-a0.6
• Minitest/AssertNilThis cop enforces the test to use assert_nil instead of using assert_equal(nil, something) or assert(something.nil?).on-a0.1
• Minitest/AssertOperatorThis cop enforces the use of assert_operator(expected, :<, actual) over assert(expected < actual).pending-a0.32
• Minitest/AssertOutputThis cop checks for opportunities to use assert_output.pending-a0.10
• Minitest/AssertPathExistsThis cop enforces the test to use assert_path_exists instead of using assert(File.exist?(path)).pending-a0.10
• Minitest/AssertPredicateThis cop enforces the test to use assert_predicate instead of using assert(obj.a_predicate_method?).pending-a0.18
• Minitest/AssertRaisesCompoundBodyThis cop enforces the block body of assert_raises { ... } to be reduced to only the raising code.pending-a0.21
• Minitest/AssertRaisesWithRegexpArgumentThis cop enforces checks for regular expression literals passed to assert_raises.pending-a0.22
• Minitest/AssertRespondToThis cop enforces the test to use assert_respond_to(object, :do_something) over assert(object.respond_to?(:do_something)).on-a0.3
• Minitest/AssertSameEnforces the use of assert_same(expected, actual) over assert(expected.equal?(actual)).pending-a0.26
• Minitest/AssertSilentThis cop enforces the test to use assert_silent { ... } instead of using assert_output('', '') { ... }.pending-a0.10
• Minitest/AssertTruthyThis cop enforces the test to use assert(actual) instead of using assert_equal(true, actual).on-A0.2
• Minitest/AssertWithExpectedArgumentThis cop tries to detect when a user accidentally used assert when they meant to use assert_equal.pending-a0.11
• Minitest/AssertionInLifecycleHookThis cop checks for usage of assertions in lifecycle hooks.pending-a0.10
• Minitest/DuplicateTestRunThis cop detects duplicate test runs caused by one test class inheriting from another.pending-a0.19
• Minitest/EmptyLineBeforeAssertionMethodsAdd empty line before assertion methods.pending-a0.23
• Minitest/FocusChecks for focused tests.pending-a0.35
• Minitest/GlobalExpectationsThis cop checks for deprecated global expectations.on-a0.7
• Minitest/LifecycleHooksOrderChecks that lifecycle hooks are declared in the order in which they will be executed.pending-a0.28
• Minitest/LiteralAsActualArgumentThis cop enforces correct order of expected and actual arguments for assert_equal.pending-a0.10
• Minitest/MultipleAssertionsThis cop checks if test cases contain too many assertion calls.pending-a0.10
• Minitest/NoAssertionsThis cop checks for at least one assertion (or flunk) in tests.opt-in-a0.12
• Minitest/NoTestCasesChecks if test class contains any test cases.opt-in-a0.30
• Minitest/NonExecutableTestMethodChecks uses of test methods outside test class.pending-a0.34
• Minitest/NonPublicTestMethodDetects non public (marked as private or protected) test methods.pending-a0.27
• Minitest/RedundantMessageArgumentDetects redundant message argument in assertion methods.pending-a0.34
• Minitest/RefuteEmptyThis cop enforces to use refute_empty instead of using refute(object.empty?).on-a0.3
• Minitest/RefuteEqualCheck if your test uses refute_equal instead of assert(expected != object) or assert(! expected == object)).on-a0.3
• Minitest/RefuteFalseCheck if your test uses refute(actual) instead of assert_equal(false, actual).on-A0.3
• Minitest/RefuteInDeltaThis cop enforces the test to use refute_in_delta instead of using refute_equal to compare floats.pending-a0.10
• Minitest/RefuteIncludesThis cop enforces the test to use refute_includes instead of using refute(collection.include?(object)).on-a0.3
• Minitest/RefuteInstanceOfThis cop enforces the test to use refute_instance_of(Class, object) over refute(object.instance_of?(Class)).on-a0.4
• Minitest/RefuteKindOfThis cop enforces the test to use refute_kind_of(Class, object) over refute(object.kind_of?(Class)).pending-a0.10
• Minitest/RefuteMatchThis cop enforces the test to use refute_match instead of using refute(matcher.match(object)).on-a0.6
• Minitest/RefuteNilThis cop enforces the test to use refute_nil instead of using refute_equal(nil, something) or refute(something.nil?).on-a0.2
• Minitest/RefuteOperatorThis cop enforces the use of refute_operator(expected, :<, actual) over refute(expected < actual).pending-a0.32
• Minitest/RefutePathExistsThis cop enforces the test to use refute_path_exists instead of using refute(File.exist?(path)).pending-a0.10
• Minitest/RefutePredicateThis cop enforces the test to use refute_predicate instead of using refute(obj.a_predicate_method?).pending-a0.18
• Minitest/RefuteRespondToThis cop enforces the test to use refute_respond_to(object, :do_something) over refute(object.respond_to?(:do_something)).on-a0.4
• Minitest/RefuteSameEnforces the use of refute_same(expected, actual) over refute(expected.equal?(actual)).pending-a0.26
• Minitest/ReturnInTestMethodEnforces the use of skip instead of return in test methods.pending-a0.31
• Minitest/SkipEnsureChecks that ensure call even if skip.pending-a0.20
• Minitest/SkipWithoutReasonChecks for skipped tests missing the skipping reason.pending-a0.24
• Minitest/TestFileNameChecks if test file names start with test_ or end with _test.rb.pending-a0.26
• Minitest/TestMethodNameThis cop enforces that test method names start with test_ prefix.pending-a0.10
• Minitest/UnreachableAssertionThis cop checks for an assert_raises block containing any unreachable assertions.pending-a0.14
• Minitest/UnspecifiedExceptionThis cop checks for a specified error in assert_raises.pending-a0.10
• Minitest/UselessAssertionDetects useless assertions (assertions that either always pass or always fail).pending-a0.26

Performance 52 rubocop-performance 1.27.0

• Performance/AncestorsIncludeUse A <= B instead of A.ancestors.include?(B).pending-A1.7
• Performance/ArraySemiInfiniteRangeSliceIdentifies places where slicing arrays with semi-infinite ranges can be replaced by Array#take and Array#drop.opt-in-A1.9
• Performance/BigDecimalWithNumericArgumentConvert numeric literal to string and pass it to BigDecimal.opt-in-a1.7
• Performance/BindCallUse bind_call(obj, args, ...) instead of bind(obj).call(args, ...).on-a1.6
• Performance/BlockGivenWithExplicitBlockCheck block argument explicitly instead of using block_given?.opt-in-a1.9
• Performance/CallerUse caller(n..n) instead of caller.on-a0.49
• Performance/CaseWhenSplatReordering when conditions with a splat to the end of the when branches can improve performance.opt-in-A0.34
• Performance/CasecmpUse casecmp rather than downcase ==, upcase ==, == downcase, or == upcase..opt-in-A0.36
• Performance/ChainArrayAllocationInstead of chaining array methods that allocate new arrays, mutate an existing array.opt-in-a0.59
• Performance/CollectionLiteralInLoopExtract Array and Hash literals outside of loops into local variables or constants.pending-a1.8
• Performance/CompareWithBlockUse sort_by(&:foo) instead of sort { |a, b| a.foo <=> b.foo }.on-a0.46
• Performance/ConcurrentMonotonicTimeUse Process.clock_gettime(Process::CLOCK_MONOTONIC) instead of Concurrent.monotonic_time.pending-a1.12
• Performance/ConstantRegexpFinds regular expressions with dynamic components that are all constants.pending-a1.9
• Performance/CountUse count instead of {select,find_all,filter,reject}...{size,count,length}.on-A0.31
• Performance/DeletePrefixUse delete_prefix instead of gsub.on-A1.6
• Performance/DeleteSuffixUse delete_suffix instead of gsub.on-A1.6
• Performance/DetectUse detect instead of select.first, find_all.first, filter.first, select.last, find_all.last, and filter.last.on-A0.30
• Performance/DoubleStartEndWithUse str.{start,end}_with?(x, ..., y, ...) instead of str.{start,end}_with?(x, ...) || str.{start,end}_with?(y, ...).on-a0.36
• Performance/EndWithUse end_with? instead of a regex match anchored to the end of a string.on-A0.36
• Performance/FixedSizeDo not compute the size of statically sized objects except in constants.on-a0.35
• Performance/FlatMapUse Enumerable#flat_map instead of Enumerable#map...Array#flatten(1) or Enumerable#collect..Array#flatten(1).on-a0.30
• Performance/InefficientHashSearchUse key? or value? instead of keys.include? or values.include?.on-A0.56
• Performance/IoReadlinesUse IO.each_line (IO#each_line) instead of IO.readlines (IO#readlines).opt-in-a1.7
• Performance/MapCompactUse filter_map instead of collection.map(&:do_something).compact.pending-A1.11
• Performance/MapMethodChainChecks if the map method is used in a chain.pending-a1.19
• Performance/MethodObjectAsBlockUse block explicitly instead of block-passing a method object.pending-a1.9
• Performance/OpenStructUse Struct instead of OpenStruct.opt-in-a0.61
• Performance/RangeIncludeUse Range#cover? instead of Range#include? (or Range#member?).on-A0.36
• Performance/RedundantBlockCallUse yield instead of block.call.on-a0.36
• Performance/RedundantEqualityComparisonBlockChecks for uses Enumerable#all?, Enumerable#any?, Enumerable#one?, or Enumerable#none? are compared with === or similar methods in block.pending-A1.10
• Performance/RedundantMatchUse =~ instead of String#match or Regexp#match in a context where the returned MatchData is not needed.on-a0.36
• Performance/RedundantMergeUse Hash#[]=, rather than Hash#merge! with a single key-value pair.on-A0.36
• Performance/RedundantSortBlockUse sort instead of sort { |a, b| a <=> b }.pending-a1.7
• Performance/RedundantSplitRegexpArgumentIdentifies places where split argument can be replaced from a deterministic regexp to a string.pending-a1.10
• Performance/RedundantStringCharsChecks for redundant String#chars.pending-a1.7
• Performance/RegexpMatchUse match? instead of Regexp#match, String#match, Symbol#match, Regexp#===, or =~ when MatchData is not used.on-a0.47
• Performance/ReverseEachUse reverse_each instead of reverse.each.on-a0.30
• Performance/ReverseFirstUse last(n).reverse instead of reverse.first(n).pending-a1.7
• Performance/SelectMapUse filter_map instead of ary.select(&:foo).map(&:bar).opt-in-a1.11
• Performance/SizeUse size instead of count for counting the number of elements in Array and Hash.on-a0.30
• Performance/SortReverseUse sort.reverse instead of sort { |a, b| b <=> a }.pending-a1.7
• Performance/SqueezeUse squeeze('a') instead of gsub(/a+/, 'a').pending-a1.7
• Performance/StartWithUse start_with? instead of a regex match anchored to the beginning of a string.on-A0.36
• Performance/StringBytesizeUse String#bytesize instead of calculating the size of the bytes array.pending-A1.23
• Performance/StringIdentifierArgumentUse symbol identifier argument instead of string identifier argument.pending-a1.13
• Performance/StringIncludeUse String#include? instead of a regex match with literal-only pattern.pending-A1.7
• Performance/StringReplacementUse tr instead of gsub when you are replacing the same number of characters. Use delete instead of gsub when you are deleting characters.on-a0.33
• Performance/SumUse sum instead of a custom array summation.pending-A1.8
• Performance/TimesMapChecks for .times.map calls.on-A0.36
• Performance/UnfreezeStringUse unary plus to get an unfrozen string literal.on-A0.50
• Performance/UriDefaultParserUse URI::DEFAULT_PARSER instead of URI::Parser.new.on-a0.50
• Performance/ZipWithoutBlockChecks for map { |id| [id] } and suggests replacing it with zip.pending-A1.24

RSpec 115 rubocop-rspec 3.10.2

• RSpec/AlignLeftLetBraceChecks that left braces for adjacent single line lets are aligned.opt-in-a1.16
• RSpec/AlignRightLetBraceChecks that right braces for adjacent single line lets are aligned.opt-in-a1.16
• RSpec/AnyInstanceCheck that instances are not being stubbed globally.on-a1.4
• RSpec/AroundBlockChecks that around blocks actually run the test.on-a1.11
• RSpec/BeCheck for expectations where be is used without argument.on-a1.25
• RSpec/BeEmptyPrefer using be_empty when checking for an empty array.on-a2.20
• RSpec/BeEqCheck for expectations where be(...) can replace eq(...).on-A2.9.0
• RSpec/BeEqlCheck for expectations where be(...) can replace eql(...).on-A1.7
• RSpec/BeNilEnsures a consistent style is used when matching nil.on-a2.9.0
• RSpec/BeforeAfterAllCheck that before/after(:all/:context) isn't being used.on-a1.12
• RSpec/ChangeByZeroPrefer negated matchers over to change.by(0).on-a2.11
• RSpec/ClassCheckEnforces consistent use of be_a or be_kind_of.on-a2.13
• RSpec/ContainExactlyChecks where contain_exactly is used.on-a2.19
• RSpec/ContextMethodcontext should not be used for specifying methods.on-a1.36
• RSpec/ContextWordingChecks that context docstring starts with an allowed prefix.on-a1.20
• RSpec/DescribeClassCheck that the first argument to the top-level describe is a constant.on-a1.0
• RSpec/DescribeMethodChecks that the second argument to describe specifies a method.on-a1.0
• RSpec/DescribeSymbolAvoid describing symbols.on-a1.15
• RSpec/DescribedClassChecks that tests use described_class.on-A1.0
• RSpec/DescribedClassModuleWrappingAvoid opening modules and defining specs within them.opt-in-a1.37
• RSpec/DialectEnforces custom RSpec dialects.opt-in-a1.33
• RSpec/DiscardedMatcherChecks for matchers that are used in void context.pending-a3.10
• RSpec/DuplicatedMetadataAvoid duplicated metadata.on-a2.16
• RSpec/EmptyExampleGroupChecks if an example group does not include any tests.on-A1.7
• RSpec/EmptyHookChecks for empty before and after hooks.on-a1.39
• RSpec/EmptyLineAfterExampleChecks if there is an empty line after example blocks.on-a1.36
• RSpec/EmptyLineAfterExampleGroupChecks if there is an empty line after example group blocks.on-a1.27
• RSpec/EmptyLineAfterFinalLetChecks if there is an empty line after the last let block.on-a1.14
• RSpec/EmptyLineAfterHookChecks if there is an empty line after hook blocks.on-a1.27
• RSpec/EmptyLineAfterSubjectChecks if there is an empty line after subject block.on-a1.14
• RSpec/EmptyMetadataAvoid empty metadata hash.on-a2.24
• RSpec/EmptyOutputCheck that the output matcher is not called with an empty string.on-a2.29
• RSpec/EqUse eq instead of be == to compare objects.on-a2.24
• RSpec/ExampleLengthChecks for long examples.on-a1.5
• RSpec/ExampleWithoutDescriptionChecks for examples without a description.on-a1.22
• RSpec/ExampleWordingChecks for common mistakes in example descriptions.on-a1.0
• RSpec/ExcessiveDocstringSpacingChecks for excessive whitespace in example descriptions.on-a2.5
• RSpec/ExpectActualChecks for expect(...) calls containing literal values.on-a1.7
• RSpec/ExpectChangeChecks for consistent style of change matcher.on-A1.22
• RSpec/ExpectInHookDo not use expect in hooks such as before.on-a1.16
• RSpec/ExpectInLetDo not use expect in let.on-a2.30
• RSpec/ExpectOutputChecks for opportunities to use expect { ... }.to output.on-a1.10
• RSpec/FocusChecks if examples are focused.on-a1.5
• RSpec/HookArgumentChecks the arguments passed to before, around, and after.on-a1.7
• RSpec/HooksBeforeExamplesChecks for before/around/after hooks that come after an example.on-a1.29
• RSpec/IdenticalEqualityAssertionChecks for equality assertions with identical expressions on both sides.on-a2.4
• RSpec/ImplicitBlockExpectationCheck that implicit block expectation syntax is not used.on-a1.35
• RSpec/ImplicitExpectCheck that a consistent implicit expectation style is used.on-a1.8
• RSpec/ImplicitSubjectChecks for usage of implicit subject (is_expected / should).on-a1.29
• RSpec/IncludeExamplesChecks for usage of include_examples.pending-A3.6
• RSpec/IndexedLetDo not set up test data using indexes (e.g., item_1, item_2).on-a2.20
• RSpec/InstanceSpyChecks for instance_double used with have_received.on-a1.12
• RSpec/InstanceVariableChecks for instance variable usage in specs.on-a1.0
• RSpec/IsExpectedSpecifyCheck for specify with is_expected and one-liner expectations.on-a2.27
• RSpec/ItBehavesLikeChecks that only one it_behaves_like style is used.on-a1.13
• RSpec/IteratedExpectationCheck that all matcher is used instead of iterating over an array.on-a1.14
• RSpec/LeadingSubjectEnforce that subject is the first definition in the test.on-a1.7
• RSpec/LeakyConstantDeclarationChecks that no class, module, or constant is declared.on-a1.35
• RSpec/LeakyLocalVariableChecks for local variables from outer scopes used inside examples.pending-a3.8
• RSpec/LetBeforeExamplesChecks for let definitions that come after an example.on-a1.16
• RSpec/LetSetupChecks unreferenced let! calls being used for test setup.on-a1.7
• RSpec/MatchArrayChecks where match_array is used.on-a2.19
• RSpec/MatchWithSimpleRegexEnforces the use of include matcher instead of match when the matcher is a simple string literal without regex-specific features.pending-a3.10
• RSpec/MessageChainCheck that chains of messages are not being stubbed.on-a1.7
• RSpec/MessageExpectationChecks for consistent message expectation style.opt-in-a1.7
• RSpec/MessageSpiesChecks that message expectations are set using spies.on-a1.9
• RSpec/MetadataStyleUse consistent metadata style.on-a2.24
• RSpec/MissingExampleGroupArgumentChecks that the first argument to an example group is not empty.on-a1.28
• RSpec/MissingExpectationTargetMethodChecks if .to, not_to or to_not are used.on-a3.0
• RSpec/MultipleDescribesChecks for multiple top-level example groups.on-a1.0
• RSpec/MultipleExpectationsChecks if examples contain too many expect calls.on-a1.7
• RSpec/MultipleMemoizedHelpersChecks if example groups contain too many let and subject calls.on-a1.43
• RSpec/MultipleSubjectsChecks if an example group defines subject multiple times.on-a1.16
• RSpec/NamedSubjectChecks for explicitly referenced test subjects.on-a1.5.3
• RSpec/NestedGroupsChecks for nested example groups.on-a1.7
• RSpec/NoExpectationExampleChecks if an example contains any expectation.on-a2.13
• RSpec/NotToNotChecks for consistent method usage for negating expectations.on-a1.4
• RSpec/OutputChecks for the use of output calls like puts and print in specs.pending-A3.9
• RSpec/OverwritingSetupChecks if there is a let/subject that overwrites an existing one.on-a1.14
• RSpec/PendingChecks for any pending or skipped examples.opt-in-a1.25
• RSpec/PendingWithoutReasonChecks for pending or skipped examples without reason.on-a2.16
• RSpec/PredicateMatcherPrefer using predicate matcher over using predicate method directly.on-A1.16
• RSpec/ReceiveCountsCheck for once and twice receive counts matchers usage.on-a1.26
• RSpec/ReceiveMessagesPrefer receive_messages over multiple receives on the same object.on-A2.23
• RSpec/ReceiveNeverPrefer not_to receive(...) over receive(...).never.on-a1.28
• RSpec/RedundantAroundRemove redundant around hook.on-a2.19
• RSpec/RedundantPredicateMatcherChecks for redundant predicate matcher.on-a2.26
• RSpec/RemoveConstChecks that remove_const is not used in specs.on-a2.26
• RSpec/RepeatedDescriptionCheck for repeated description strings in example groups.on-a1.9
• RSpec/RepeatedExampleCheck for repeated examples within example groups.on-a1.10
• RSpec/RepeatedExampleGroupBodyCheck for repeated describe and context block body.on-a1.38
• RSpec/RepeatedExampleGroupDescriptionCheck for repeated example group descriptions.on-a1.38
• RSpec/RepeatedIncludeExampleCheck for repeated include of shared examples.on-a1.44
• RSpec/RepeatedSubjectCallChecks for repeated calls to subject missing that it is memoized.on-a2.27
• RSpec/ReturnFromStubChecks for consistent style of stub's return setting.on-a1.16
• RSpec/ScatteredLetChecks for let scattered across the example group.on-a1.14
• RSpec/ScatteredSetupChecks for setup scattered across multiple hooks in an example group.on-a1.10
• RSpec/SharedContextChecks for proper shared_context and shared_examples usage.on-a1.13
• RSpec/SharedExamplesChecks for consistent style for shared example names.on-a1.25
• RSpec/SingleArgumentMessageChainChecks that chains of messages contain more than one element.on-a1.9
• RSpec/SkipBlockInsideExampleChecks for passing a block to skip within examples.on-a2.19
• RSpec/SortMetadataSort RSpec metadata alphabetically.on-a2.14
• RSpec/SpecFilePathFormatChecks that spec file paths are consistent and well-formed.on-a2.24
• RSpec/SpecFilePathSuffixChecks that spec file paths suffix are consistent and well-formed.on-a2.24
• RSpec/StubbedMockChecks that message expectations do not have a configured response.on-a1.44
• RSpec/SubjectDeclarationEnsure that subject is defined using subject helper.on-a2.5
• RSpec/SubjectStubChecks for stubbed test subjects.on-a1.7
• RSpec/UndescriptiveLiteralsDescriptionDescription should be descriptive.on-a2.29
• RSpec/UnspecifiedExceptionChecks for a specified error in checking raised errors.on-a1.30
• RSpec/VariableDefinitionChecks that memoized helpers names are symbols or strings.on-a1.40
• RSpec/VariableNameChecks that memoized helper names use the configured style.on-a1.40
• RSpec/VerifiedDoubleReferenceChecks for consistent verified double reference style.on-A2.10.0
• RSpec/VerifiedDoublesPrefer using verifying doubles over normal doubles.on-a1.2.1
• RSpec/VoidExpectChecks void expect().on-a1.16
• RSpec/YieldChecks for calling a block within a stub.on-a1.32

RSpecRails 10 rubocop-rspec_rails 2.33.0

• RSpecRails/AvoidSetupHookChecks that tests use RSpec before instead of Rails setup.pending-a2.4
• RSpecRails/FileFixturePrefer file_fixture over hardcoded paths into spec/fixtures.pending-a2.33
• RSpecRails/HaveHttpStatusChecks that tests use have_http_status instead of equality matchers.pending-A2.12
• RSpecRails/HttpStatusEnforces use of symbolic or numeric value to describe HTTP status.on-a1.23
• RSpecRails/HttpStatusNameConsistencyEnforces consistency by using the current HTTP status names.pending-a2.32
• RSpecRails/InferredSpecTypeIdentifies redundant spec type.pending-A2.14
• RSpecRails/MinitestAssertionsDetects Minitest-like matchers.pending-a2.17
• RSpecRails/NegationBeValidEnforces use of be_invalid or not_to for negated be_valid.pending-A2.23
• RSpecRails/ReceivePerformLaterPrefer have_enqueued_job over receive(:perform_later).pending-a2.33
• RSpecRails/TravelAroundChecks for time travel helpers in around hooks.pending-A2.19

Rails 138 rubocop-rails 2.38.0

• Rails/ActionControllerFlashBeforeRenderUse flash.now instead of flash before render.pending-A2.16
• Rails/ActionControllerTestCaseUse ActionDispatch::IntegrationTest instead of ActionController::TestCase.pending-A2.14
• Rails/ActionFilterEnforces consistent use of action filter methods.opt-in-a0.19
• Rails/ActionOrderEnforce consistent ordering of controller actions.pending-a2.17
• Rails/ActiveRecordAliasesAvoid Active Record aliases: Use update instead of update_attributes. Use update! instead of update_attributes!.on-A0.53
• Rails/ActiveRecordCallbacksOrderOrder callback declarations in the order in which they will be executed.pending-a2.7
• Rails/ActiveRecordOverrideCheck for overriding Active Record methods instead of using callbacks.on-a0.67
• Rails/ActiveSupportAliasesAvoid ActiveSupport aliases of standard ruby methods: String#starts_with?, String#ends_with?, Array#append, Array#prepend.on-a0.48
• Rails/ActiveSupportOnLoadUse ActiveSupport.on_load(...) to patch Rails framework classes.pending-A2.16
• Rails/AddColumnIndexRails migrations don't make use of a given index key, but also doesn't given an error when it's used, so it makes it seem like an index might be used.pending-a2.11
• Rails/AfterCommitOverrideEnforces that there is only one call to after_commit (and its aliases - after_create_commit, after_update_commit, and after_destroy_commit) with the same callback name per model.pending-a2.8
• Rails/ApplicationControllerCheck that controllers subclass ApplicationController.on-A2.4
• Rails/ApplicationJobCheck that jobs subclass ApplicationJob.on-A0.49
• Rails/ApplicationMailerCheck that mailers subclass ApplicationMailer.on-A2.4
• Rails/ApplicationRecordCheck that models subclass ApplicationRecord.on-A0.49
• Rails/ArelStarEnforces Arel.star instead of "*" for expanded columns.on-A2.9
• Rails/AssertNotUse assert_not instead of assert !.on-a0.56
• Rails/AttributeDefaultBlockValuePass method call in block for attribute option default.pending-a2.9
• Rails/BelongsToUse optional: true instead of required: false for belongs_to relations.on-a0.62
• Rails/BlankEnforces use of blank?.on-A0.48
• Rails/BulkChangeTableCheck whether alter queries are combinable.on-a0.57
• Rails/CompactBlankChecks if collection can be blank-compacted with compact_blank.pending-A2.13
• Rails/ContentTagUse tag.something instead of tag(:something).on-a2.6
• Rails/CreateTableWithTimestampsChecks the migration for which timestamps are not included when creating a new table.on-a0.52
• Rails/DangerousColumnNamesAvoid dangerous column names.pending-a2.21
• Rails/DateChecks the correct usage of date aware methods, such as Date.today, Date.current etc.on-A0.30
• Rails/DefaultScopeAvoid use of default_scope.opt-in-a2.7
• Rails/DelegatePrefer delegate method for delegations.on-a0.21
• Rails/DelegateAllowBlankDo not use allow_blank as an option to delegate.on-a0.44
• Rails/DeprecatedActiveModelErrorsMethodsAvoid manipulating ActiveModel errors hash directly.pending-A2.14
• Rails/DotSeparatedKeysEnforces the use of dot-separated keys instead of :scope options in I18n translation methods.pending-a2.15
• Rails/DuplicateAssociationDon't repeat associations in a model.pending-a2.14
• Rails/DuplicateScopeMultiple scopes share this same expression.pending-a2.14
• Rails/DurationArithmeticDo not use duration as arithmetic operand with Time.current.pending-a2.13
• Rails/DynamicFindByUse find_by instead of dynamic find_by_*.on-A0.44
• Rails/EagerEvaluationLogMessageChecks that blocks are used for interpolated strings passed to Rails.logger.debug.pending-a2.11
• Rails/EnumHashPrefer hash syntax over array syntax when defining enums.on-a2.3
• Rails/EnumSyntaxUse positional arguments over keyword arguments when defining enums.pending-a2.26
• Rails/EnumUniquenessAvoid duplicate integers in hash-syntax enum declaration.on-a0.46
• Rails/EnvUse Feature Flags or config instead of Rails.env.opt-in-a2.34
• Rails/EnvLocalUse Rails.env.local? instead of Rails.env.development? || Rails.env.test?.pending-a2.22
• Rails/EnvironmentComparisonFavor Rails.env.production? over Rails.env == 'production'.on-a0.52
• Rails/EnvironmentVariableAccessDo not access ENV directly after initialization.opt-in-a2.10
• Rails/ExitFavor fail, break, return, etc. over exit in application or library code outside of Rake files to avoid exits during unit testing or running in production.on-a0.41
• Rails/ExpandedDateRangeChecks for expanded date range.pending-a2.11
• Rails/FilePathUse Rails.root.join for file path joining.on-a0.47
• Rails/FindByPrefer find_by over where.first.on-a0.30
• Rails/FindByIdFavor the use of find over where.take!, find_by!, and find_by_id! when you need to retrieve a single record by primary key when you expect it to be found.pending-a2.7
• Rails/FindByOrAssignmentMemoizationAvoid memoizing find_by results with ||=.pending-A2.33
• Rails/FindEachPrefer all.find_each over all.each.on-A0.30
• Rails/FreezeTimePrefer freeze_time over travel_to with an argument of the current time.pending-A2.16
• Rails/HasAndBelongsToManyPrefer has_many :through to has_and_belongs_to_many.on-a0.12
• Rails/HasManyOrHasOneDependentDefine the dependent option to the has_many and has_one associations.on-a0.50
• Rails/HelperInstanceVariableDo not use instance variables in helpers.on-a2.0
• Rails/HttpPositionalArgumentsUse keyword arguments instead of positional arguments in http method calls.on-a0.44
• Rails/HttpStatusEnforces use of symbolic or numeric value to define HTTP status.on-a0.54
• Rails/HttpStatusNameConsistencyEnforces consistency by using the current HTTP status names.pending-a2.34
• Rails/I18nLazyLookupChecks for places where I18n "lazy" lookup can be used.pending-a2.14
• Rails/I18nLocaleAssignmentPrefer the usage of I18n.with_locale instead of manually updating I18n.locale value.pending-a2.11
• Rails/I18nLocaleTextsEnforces use of I18n and locale files instead of locale specific strings.pending-a2.14
• Rails/IgnoredColumnsAssignmentLooks for assignments of ignored_columns that override previous assignments.pending-A2.17
• Rails/IgnoredSkipActionFilterOptionChecks that if and only (or except) are not used together as options of skip_* action filter.on-a0.63
• Rails/IndexByPrefer index_by over each_with_object, to_h, or map.on-a2.5
• Rails/IndexWithPrefer index_with over each_with_object, to_h, or map.on-A2.5
• Rails/InquiryPrefer Ruby's comparison operators over Active Support's Array#inquiry and String#inquiry.pending-a2.7
• Rails/InverseOfChecks for associations where the inverse cannot be determined automatically.on-a0.52
• Rails/LexicallyScopedActionFilterChecks that methods specified in the filter's only or except options are explicitly defined in the class.on-a0.52
• Rails/LinkToBlankChecks that link_to with a target: "_blank" have a rel: "noopener" option passed to them.on-a0.62
• Rails/MailerNameMailer should end with Mailer suffix.pending-A2.7
• Rails/MatchRouteDon't use match to define any routes unless there is a need to map multiple request types among [:get, :post, :patch, :put, :delete] to a single action using the :via option.pending-a2.7
• Rails/MigrationClassNameThe class name of the migration should match its file name.pending-a2.14
• Rails/MultipleRoutePathsChecks for mapping a route with multiple paths, which is deprecated and will be removed in Rails 8.1.pending-a2.29
• Rails/NegateIncludePrefer collection.exclude?(obj) over !collection.include?(obj).pending-A2.7
• Rails/NotNullColumnDo not add a NOT NULL column without a default value to existing tables.on-a0.43
• Rails/OrderArgumentsPrefer symbol arguments over strings in order method.pending-A2.33
• Rails/OrderByIdDo not use the id column for ordering. Use a timestamp column to order chronologically.opt-in-a2.8
• Rails/OutputChecks for calls to puts, print, etc.on-A0.15
• Rails/OutputSafetyThe use of html_safe or raw may be a security risk.on-a0.41
• Rails/PickPrefer pick over pluck(...).first.on-A2.6
• Rails/PluckPrefer pluck over map { ... }.pending-A2.7
• Rails/PluckIdUse ids instead of pluck(:id) or pluck(primary_key).opt-in-A2.7
• Rails/PluckInWhereUse select instead of pluck in where query methods.pending-A2.7
• Rails/PluralizationGrammarChecks for incorrect grammar when using methods like 3.day.ago.on-a0.35
• Rails/PresenceChecks code that can be written more easily using Object#presence defined by Active Support.on-a0.52
• Rails/PresentEnforces use of present?.on-a0.48
• Rails/RakeEnvironmentInclude :environment as a dependency for all Rake tasks.on-A2.4
• Rails/ReadWriteAttributeChecks for read_attribute(:attr) and write_attribute(:attr, val).on-a0.20
• Rails/RedirectBackOrToUse redirect_back_or_to instead of redirect_back with fallback_location option.pending-a2.34
• Rails/RedundantActiveRecordAllMethodDetect redundant all used as a receiver for Active Record query methods.pending-A2.21
• Rails/RedundantAllowNilFinds redundant use of allow_nil when allow_blank is set to certain values in model validations.on-a0.67
• Rails/RedundantForeignKeyChecks for associations where the :foreign_key option is redundant.on-a2.6
• Rails/RedundantPresenceValidationOnBelongsToChecks for redundant presence validation on belongs_to association.pending-A2.13
• Rails/RedundantReceiverInWithOptionsChecks for redundant receiver in with_options.on-a0.52
• Rails/RedundantTravelBackChecks for redundant travel_back calls.pending-a2.12
• Rails/ReflectionClassNameUse a string for class_name option value in the definition of a reflection.on-A0.64
• Rails/RefuteMethodsUse assert_not methods instead of refute methods.on-a0.56
• Rails/RelativeDateConstantDo not assign relative date to constants.on-A0.48
• Rails/RenderInlinePrefer using a template over inline rendering.pending-a2.7
• Rails/RenderPlainTextPrefer render plain: over render text:.pending-a2.7
• Rails/RequestRefererUse consistent syntax for request.referer.on-a0.41
• Rails/RequireDependencyDo not use require_dependency when running in Zeitwerk mode. require_dependency is for autoloading in classic mode.opt-in-a2.10
• Rails/ResponseParsedBodyPrefer response.parsed_body to custom parsing logic for response.body.pending-A2.18
• Rails/ReversibleMigrationChecks whether the change method of the migration file is reversible.on-a0.47
• Rails/ReversibleMigrationMethodDefinitionChecks whether the migration implements either a change method or both an up and a down method.opt-in-a2.10
• Rails/RootJoinChainUse a single #join instead of chaining on Rails.root or Rails.public_path.pending-a2.13
• Rails/RootPathnameMethodsUse Rails.root IO methods instead of passing it to File.pending-A2.16
• Rails/RootPublicPathFavor Rails.public_path over Rails.root with 'public'.pending-a2.15
• Rails/SafeNavigationUse Ruby's safe navigation operator (&.) instead of try!.on-a0.43
• Rails/SafeNavigationWithBlankAvoid foo&.blank? in conditionals.on-A2.4
• Rails/SaveBangIdentifies possible cases where Active Record save! or related should be used.opt-in-A0.42
• Rails/SchemaCommentEnforces the use of the comment option when adding a new table or column to the database during a migration.opt-in-a2.13
• Rails/ScopeArgsChecks the arguments of ActiveRecord scopes.on-a0.19
• Rails/SelectMapChecks for uses of select(:column_name) with map(&:column_name).pending-A2.21
• Rails/ShortI18nUse the short form of the I18n methods: t instead of translate and l instead of localize.pending-a2.7
• Rails/SkipsModelValidationsUse methods that skips model validations with caution. See reference for more information.on-a0.47
• Rails/SquishedSQLHeredocsChecks SQL heredocs to use .squish.pending-A2.8
• Rails/StripHeredocEnforces the use of squiggly heredoc over strip_heredoc.pending-a2.15
• Rails/StrongParametersExpectEnforces the use of ActionController::Parameters#expect as a method for strong parameter handling.pending-A2.29
• Rails/TableNameAssignmentDo not use self.table_name =. Use Inflections or table_name_prefix instead.opt-in-a2.14
• Rails/ThreeStateBooleanColumnAdd a default value and a NOT NULL constraint to boolean columns.pending-a2.19
• Rails/TimeZoneChecks the correct usage of time zone aware methods.on-A0.30
• Rails/TimeZoneAssignmentPrefer the usage of Time.use_zone instead of manually updating Time.zone value.pending-a2.10
• Rails/ToFormattedSChecks for consistent uses of to_fs or to_formatted_s.pending-a2.15
• Rails/ToSWithArgumentIdentifies passing any argument to #to_s.pending-A2.16
• Rails/TopLevelHashWithIndifferentAccessIdentifies top-level HashWithIndifferentAccess.pending-a2.16
• Rails/TransactionExitStatementAvoid the usage of return, break and throw in transaction blocks.pending-a2.14
• Rails/UniqBeforePluckPrefer the use of uniq or distinct before pluck.on-A0.40
• Rails/UniqueValidationWithoutIndexUniqueness validation should have a unique index on the database column.on-a2.5
• Rails/UnknownEnvUse correct environment name.on-a0.51
• Rails/UnusedIgnoredColumnsRemove a column that does not exist from ignored_columns.opt-in-a2.11
• Rails/UnusedRenderContentDo not specify body content for a response with a non-content status code.pending-a2.21
• Rails/ValidationUse validates :attribute, hash of validations.on-a0.9
• Rails/WhereEqualsPass conditions to where and where.not as a hash instead of manually constructing SQL.pending-A2.9
• Rails/WhereExistsPrefer exists?(...) over where(...).exists?.pending-A2.7
• Rails/WhereMissingUse where.missing(...) to find missing relationship records.pending-a2.16
• Rails/WhereNotUse where.not(...) instead of manually constructing negated SQL in where.pending-a2.8
• Rails/WhereNotWithMultipleConditionsDo not use where.not(...) with multiple conditions.pending-a2.17
• Rails/WhereRangeUse ranges in where instead of manually constructing SQL.pending-A2.25

ThreadSafety 10 rubocop-thread_safety 0.8.0

• ThreadSafety/ActiveSupportCallbacksAvoid mutating ActiveSupport callback chains at runtime.pending-a0.8
• ThreadSafety/ClassAndModuleAttributesAvoid mutating class and module attributes.on-a
• ThreadSafety/ClassInstanceVariableAvoid class instance variables.on-a
• ThreadSafety/DirChdirAvoid using Dir.chdir due to its process-wide effect.on-a
• ThreadSafety/EnvMutationAvoid mutating ENV due to its process-wide effect.opt-in-a0.8
• ThreadSafety/LazySynchronizationPrimitiveDo not lazily initialize synchronization primitives with ||=.pending-a0.8
• ThreadSafety/MethodRedefinitionDo not use remove_method followed by method definition.pending-a0.8
• ThreadSafety/MutableClassInstanceVariableDo not assign mutable objects to class instance variables.on-A
• ThreadSafety/NewThreadAvoid starting new threads. Let a framework like Sidekiq handle the threads.on-a
• ThreadSafety/RackMiddlewareInstanceVariableAvoid instance variables in Rack middleware.on-a