default.yml

# This is the default configuration file.

Performance:
  Enabled: true
  DocumentationBaseURL: https://docs.rubocop.org/rubocop-performance

Performance/AncestorsInclude:
  Description: 'Use `A <= B` instead of `A.ancestors.include?(B)`.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#ancestorsinclude-vs--code'
  Enabled: 'pending'
  Safe: false
  VersionAdded: '1.7'

Performance/ArraySemiInfiniteRangeSlice:
  Description: 'Identifies places where slicing arrays with semi-infinite ranges can be replaced by `Array#take` and `Array#drop`.'
  # This cop was created due to a mistake in microbenchmark.
  # Refer https://github.com/rubocop/rubocop-performance/pull/175#issuecomment-731892717
  Enabled: false
  # Unsafe for string slices because strings do not have `#take` and `#drop` methods.
  Safe: false
  VersionAdded: '1.9'

Performance/BigDecimalWithNumericArgument:
  Description: 'Convert numeric literal to string and pass it to `BigDecimal`.'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/BindCall:
  Description: 'Use `bind_call(obj, args, ...)` instead of `bind(obj).call(args, ...)`.'
  Enabled: true
  VersionAdded: '1.6'

Performance/BlockGivenWithExplicitBlock:
  Description: 'Check block argument explicitly instead of using `block_given?`.'
  Enabled: pending
  VersionAdded: '1.9'

Performance/Caller:
  Description: >-
             Use `caller(n..n)` instead of `caller`.
  Enabled: true
  VersionAdded: '0.49'
  VersionChanged: '1.9'

Performance/CaseWhenSplat:
  Description: >-
                 Reordering `when` conditions with a splat to the end
                 of the `when` branches can improve performance.
  Enabled: false
  SafeAutoCorrect: false
  VersionAdded: '0.34'
  VersionChanged: '1.13'

Performance/Casecmp:
  Description: >-
             Use `casecmp` rather than `downcase ==`, `upcase ==`, `== downcase`, or `== upcase`..
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#stringcasecmp-vs-stringdowncase---code'
  Enabled: true
  Safe: false
  VersionAdded: '0.36'

Performance/ChainArrayAllocation:
  Description: >-
                  Instead of chaining array methods that allocate new arrays, mutate an
                  existing array.
  Reference: 'https://twitter.com/schneems/status/1034123879978029057'
  Enabled: false
  VersionAdded: '0.59'

Performance/CollectionLiteralInLoop:
  Description: 'Extract Array and Hash literals outside of loops into local variables or constants.'
  Enabled: 'pending'
  VersionAdded: '1.8'
  # Min number of elements to consider an offense
  MinSize: 1

Performance/CompareWithBlock:
  Description: 'Use `sort_by(&:foo)` instead of `sort { |a, b| a.foo <=> b.foo }`.'
  Enabled: true
  VersionAdded: '0.46'

Performance/ConcurrentMonotonicTime:
  Description: 'Use `Process.clock_gettime(Process::CLOCK_MONOTONIC)` instead of `Concurrent.monotonic_time`.'
  Reference: 'https://github.com/rails/rails/pull/43502'
  Enabled: pending
  VersionAdded: '1.12'

Performance/ConstantRegexp:
  Description: 'Finds regular expressions with dynamic components that are all constants.'
  Enabled: pending
  VersionAdded: '1.9'
  VersionChanged: '1.10'

Performance/Count:
  Description: >-
                  Use `count` instead of `{select,find_all,filter,reject}...{size,count,length}`.
  # This cop has known compatibility issues with `ActiveRecord` and other
  # frameworks. ActiveRecord's `count` ignores the block that is passed to it.
  # For more information, see the documentation in the cop itself.
  SafeAutoCorrect: false
  Enabled: true
  VersionAdded: '0.31'
  VersionChanged: '1.8'

Performance/DeletePrefix:
  Description: 'Use `delete_prefix` instead of `gsub`.'
  Enabled: true
  Safe: false
  SafeMultiline: true
  VersionAdded: '1.6'
  VersionChanged: '1.11'

Performance/DeleteSuffix:
  Description: 'Use `delete_suffix` instead of `gsub`.'
  Enabled: true
  Safe: false
  SafeMultiline: true
  VersionAdded: '1.6'
  VersionChanged: '1.11'

Performance/Detect:
  Description: >-
                  Use `detect` instead of `select.first`, `find_all.first`, `filter.first`,
                  `select.last`, `find_all.last`, and `filter.last`.
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#enumerabledetect-vs-enumerableselectfirst-code'
  # This cop has known compatibility issues with `ActiveRecord` and other
  # frameworks. `ActiveRecord` does not implement a `detect` method and `find`
  # has its own meaning. Correcting `ActiveRecord` methods with this cop
  # should be considered unsafe.
  SafeAutoCorrect: false
  Enabled: true
  VersionAdded: '0.30'
  VersionChanged: '1.8'

Performance/DoubleStartEndWith:
  Description: >-
                  Use `str.{start,end}_with?(x, ..., y, ...)`
                  instead of `str.{start,end}_with?(x, ...) || str.{start,end}_with?(y, ...)`.
  Enabled: true
  VersionAdded: '0.36'
  VersionChanged: '0.48'
  # Used to check for `starts_with?` and `ends_with?`.
  # These methods are defined by Active Support.
  IncludeActiveSupportAliases: false

Performance/EndWith:
  Description: 'Use `end_with?` instead of a regex match anchored to the end of a string.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#stringmatch-vs-stringstart_withstringend_with-code-start-code-end'
  # This will change to a new method call which isn't guaranteed to be on the
  # object. Switching these methods has to be done with knowledge of the types
  # of the variables which rubocop doesn't have.
  SafeAutoCorrect: false
  Enabled: true
  SafeMultiline: true
  VersionAdded: '0.36'
  VersionChanged: '1.10'

Performance/FixedSize:
  Description: 'Do not compute the size of statically sized objects except in constants.'
  Enabled: true
  VersionAdded: '0.35'

Performance/FlatMap:
  Description: >-
                  Use `Enumerable#flat_map`
                  instead of `Enumerable#map...Array#flatten(1)`
                  or `Enumerable#collect..Array#flatten(1)`.
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#enumerablemaparrayflatten-vs-enumerableflat_map-code'
  Enabled: true
  VersionAdded: '0.30'
  EnabledForFlattenWithoutParams: false
  # If enabled, this cop will warn about usages of
  # `flatten` being called without any parameters.
  # This can be dangerous since `flat_map` will only flatten 1 level, and
  # `flatten` without any parameters can flatten multiple levels.

Performance/InefficientHashSearch:
  Description: 'Use `key?` or `value?` instead of `keys.include?` or `values.include?`.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#hashkey-instead-of-hashkeysinclude-code'
  Enabled: true
  VersionAdded: '0.56'
  Safe: false

Performance/IoReadlines:
  Description: 'Use `IO.each_line` (`IO#each_line`) instead of `IO.readlines` (`IO#readlines`).'
  Reference: 'https://docs.gitlab.com/ee/development/performance.html#reading-from-files-and-other-data-sources'
  Enabled: false
  VersionAdded: '1.7'

Performance/MapCompact:
  Description: 'Use `filter_map` instead of `collection.map(&:do_something).compact`.'
  Enabled: pending
  SafeAutoCorrect: false
  VersionAdded: '1.11'

Performance/MethodObjectAsBlock:
  Description: 'Use block explicitly instead of block-passing a method object.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#normal-way-to-apply-method-vs-method-code'
  Enabled: pending
  VersionAdded: '1.9'

Performance/OpenStruct:
  Description: 'Use `Struct` instead of `OpenStruct`.'
  Enabled: false
  VersionAdded: '0.61'
  Safe: false

Performance/RangeInclude:
  Description: 'Use `Range#cover?` instead of `Range#include?` (or `Range#member?`).'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#cover-vs-include-code'
  Enabled: true
  VersionAdded: '0.36'
  VersionChanged: '1.7'
  Safe: false

Performance/RedundantBlockCall:
  Description: 'Use `yield` instead of `block.call`.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#proccall-and-block-arguments-vs-yieldcode'
  Enabled: true
  VersionAdded: '0.36'

Performance/RedundantEqualityComparisonBlock:
  Description: >-
                  Checks for uses `Enumerable#all?`, `Enumerable#any?`, `Enumerable#one?`,
                  or `Enumerable#none?` are compared with `===` or similar methods in block.
  Reference: 'https://github.com/rails/rails/pull/41363'
  Enabled: pending
  Safe: false
  VersionAdded: '1.10'

Performance/RedundantMatch:
  Description: >-
                  Use `=~` instead of `String#match` or `Regexp#match` in a context where the
                  returned `MatchData` is not needed.
  Enabled: true
  VersionAdded: '0.36'

Performance/RedundantMerge:
  Description: 'Use Hash#[]=, rather than Hash#merge! with a single key-value pair.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#hashmerge-vs-hash-code'
  Enabled: true
  Safe: false
  VersionAdded: '0.36'
  VersionChanged: '1.11'
  # Max number of key-value pairs to consider an offense
  MaxKeyValuePairs: 2

Performance/RedundantSortBlock:
  Description: 'Use `sort` instead of `sort { |a, b| a <=> b }`.'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/RedundantSplitRegexpArgument:
  Description: 'Identifies places where `split` argument can be replaced from a deterministic regexp to a string.'
  Enabled: pending
  VersionAdded: '1.10'

Performance/RedundantStringChars:
  Description: 'Checks for redundant `String#chars`.'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/RegexpMatch:
  Description: >-
                  Use `match?` instead of `Regexp#match`, `String#match`, `Symbol#match`,
                  `Regexp#===`, or `=~` when `MatchData` is not used.
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#regexp-vs-stringmatch-vs-string-vs-stringmatch-code-'
  Enabled: true
  VersionAdded: '0.47'

Performance/ReverseEach:
  Description: 'Use `reverse_each` instead of `reverse.each`.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#enumerablereverseeach-vs-enumerablereverse_each-code'
  Enabled: true
  VersionAdded: '0.30'

Performance/ReverseFirst:
  Description: 'Use `last(n).reverse` instead of `reverse.first(n)`.'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/SelectMap:
  Description: 'Use `filter_map` instead of `ary.select(&:foo).map(&:bar)`.'
  Enabled: false
  VersionAdded: '1.11'

Performance/Size:
  Description: >-
                  Use `size` instead of `count` for counting
                  the number of elements in `Array` and `Hash`.
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#arraylength-vs-arraysize-vs-arraycount-code'
  Enabled: true
  VersionAdded: '0.30'

Performance/SortReverse:
  Description: 'Use `sort.reverse` instead of `sort { |a, b| b <=> a }`.'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/Squeeze:
  Description: "Use `squeeze('a')` instead of `gsub(/a+/, 'a')`."
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#remove-extra-spaces-or-other-contiguous-characters-code'
  Enabled: 'pending'
  VersionAdded: '1.7'

Performance/StartWith:
  Description: 'Use `start_with?` instead of a regex match anchored to the beginning of a string.'
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#stringmatch-vs-stringstart_withstringend_with-code-start-code-end'
  # This will change to a new method call which isn't guaranteed to be on the
  # object. Switching these methods has to be done with knowledge of the types
  # of the variables which rubocop doesn't have.
  SafeAutoCorrect: false
  Enabled: true
  SafeMultiline: true
  VersionAdded: '0.36'
  VersionChanged: '1.10'

Performance/StringIdentifierArgument:
  Description: 'Use symbol identifier argument instead of string identifier argument.'
  Enabled: pending
  VersionAdded: '1.13'

Performance/StringInclude:
  Description: 'Use `String#include?` instead of a regex match with literal-only pattern.'
  Enabled: 'pending'
  SafeAutoCorrect: false
  VersionAdded: '1.7'
  VersionChanged: '1.12'

Performance/StringReplacement:
  Description: >-
                  Use `tr` instead of `gsub` when you are replacing the same
                  number of characters. Use `delete` instead of `gsub` when
                  you are deleting characters.
  Reference: 'https://github.com/JuanitoFatas/fast-ruby#stringgsub-vs-stringtr-code'
  Enabled: true
  VersionAdded: '0.33'

Performance/Sum:
  Description: 'Use `sum` instead of a custom array summation.'
  SafeAutoCorrect: false
  Reference: 'https://blog.bigbinary.com/2016/11/02/ruby-2-4-introduces-enumerable-sum.html'
  Enabled: 'pending'
  VersionAdded: '1.8'
  VersionChanged: '1.13'
  OnlySumOrWithInitialValue: false

Performance/TimesMap:
  Description: 'Checks for .times.map calls.'
  Enabled: true
  # See https://github.com/rubocop/rubocop/issues/4658
  SafeAutoCorrect: false
  VersionAdded: '0.36'
  VersionChanged: '1.13'

Performance/UnfreezeString:
  Description: 'Use unary plus to get an unfrozen string literal.'
  Enabled: true
  SafeAutoCorrect: false
  VersionAdded: '0.50'
  VersionChanged: '1.9'

Performance/UriDefaultParser:
  Description: 'Use `URI::DEFAULT_PARSER` instead of `URI::Parser.new`.'
  Enabled: true
  VersionAdded: '0.50'