-
-
Notifications
You must be signed in to change notification settings - Fork 79
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Add new
Performance/ArraySemiInfiniteRangeSlice
cop
- Loading branch information
Showing
7 changed files
with
194 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
74 changes: 74 additions & 0 deletions
74
lib/rubocop/cop/performance/array_semi_infinite_range_slice.rb
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,74 @@ | ||
# frozen_string_literal: true | ||
|
||
module RuboCop | ||
module Cop | ||
module Performance | ||
# This cop identifies places where slicing arrays with semi-infinite ranges | ||
# can be replaced by `Array#take` and `Array#drop`. | ||
# | ||
# @example | ||
# # bad | ||
# # array[..2] | ||
# # array[...2] | ||
# # array[2..] | ||
# # array[2...] | ||
# # array.slice(..2) | ||
# | ||
# # good | ||
# array.take(3) | ||
# array.take(2) | ||
# array.drop(2) | ||
# array.drop(2) | ||
# array.take(3) | ||
# | ||
class ArraySemiInfiniteRangeSlice < Base | ||
include RangeHelp | ||
extend AutoCorrector | ||
extend TargetRubyVersion | ||
|
||
minimum_target_ruby_version 2.7 | ||
|
||
MSG = 'Use `%<prefer>s` instead of `%<current>s` with semi-infinite range.' | ||
|
||
SLICE_METHODS = Set[:[], :slice].freeze | ||
RESTRICT_ON_SEND = SLICE_METHODS | ||
|
||
def_node_matcher :endless_range_slice?, <<~PATTERN | ||
(send $_ $%SLICE_METHODS $#endless_range?) | ||
PATTERN | ||
|
||
def_node_matcher :endless_range?, <<~PATTERN | ||
{ | ||
({irange erange} nil? (int positive?)) | ||
({irange erange} (int positive?) nil?) | ||
} | ||
PATTERN | ||
|
||
def on_send(node) | ||
endless_range_slice?(node) do |receiver, method_name, range_node| | ||
prefer = range_node.begin ? :drop : :take | ||
message = format(MSG, prefer: prefer, current: method_name) | ||
|
||
add_offense(node, message: message) do |corrector| | ||
corrector.replace(node, correction(receiver, range_node)) | ||
end | ||
end | ||
end | ||
|
||
private | ||
|
||
def correction(receiver, range_node) | ||
method_call = if range_node.begin | ||
"drop(#{range_node.begin.value})" | ||
elsif range_node.irange_type? | ||
"take(#{range_node.end.value + 1})" | ||
else | ||
"take(#{range_node.end.value})" | ||
end | ||
|
||
"#{receiver.source}.#{method_call}" | ||
end | ||
end | ||
end | ||
end | ||
end |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
73 changes: 73 additions & 0 deletions
73
spec/rubocop/cop/performance/array_semi_infinite_range_slice_spec.rb
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,73 @@ | ||
# frozen_string_literal: true | ||
|
||
RSpec.describe RuboCop::Cop::Performance::ArraySemiInfiniteRangeSlice, :config do | ||
subject(:cop) { described_class.new(config) } | ||
|
||
# TODO: The following is no longer required when RuboCop 0.78 or lower support will be dropped. | ||
# https://github.com/rubocop-hq/rubocop/pull/7605 | ||
let(:ruby_version) { 2.7 } | ||
|
||
context 'TargetRubyVersion >= 2.7', :ruby27 do | ||
it 'registers an offense and corrects when using `[]` with beginless range' do | ||
expect_offense(<<~RUBY) | ||
array[..2] | ||
^^^^^^^^^^ Use `take` instead of `[]` with semi-infinite range. | ||
array[...2] | ||
^^^^^^^^^^^ Use `take` instead of `[]` with semi-infinite range. | ||
RUBY | ||
|
||
expect_correction(<<~RUBY) | ||
array.take(3) | ||
array.take(2) | ||
RUBY | ||
end | ||
|
||
it 'registers an offense and corrects when using `[]` with endless range' do | ||
expect_offense(<<~RUBY) | ||
array[2..] | ||
^^^^^^^^^^ Use `drop` instead of `[]` with semi-infinite range. | ||
array[2...] | ||
^^^^^^^^^^^ Use `drop` instead of `[]` with semi-infinite range. | ||
RUBY | ||
|
||
expect_correction(<<~RUBY) | ||
array.drop(2) | ||
array.drop(2) | ||
RUBY | ||
end | ||
|
||
it 'registers an offense and corrects when using `slice` with semi-infinite ranges' do | ||
expect_offense(<<~RUBY) | ||
array.slice(2..) | ||
^^^^^^^^^^^^^^^^ Use `drop` instead of `slice` with semi-infinite range. | ||
array.slice(..2) | ||
^^^^^^^^^^^^^^^^ Use `take` instead of `slice` with semi-infinite range. | ||
RUBY | ||
|
||
expect_correction(<<~RUBY) | ||
array.drop(2) | ||
array.take(3) | ||
RUBY | ||
end | ||
|
||
it 'does not register an offense when using `[]` with full range' do | ||
expect_no_offenses(<<~RUBY) | ||
array[0..2] | ||
RUBY | ||
end | ||
|
||
it 'does not register an offense when using `[]` with semi-infinite range with non literal' do | ||
expect_no_offenses(<<~RUBY) | ||
array[..index] | ||
array[index..] | ||
RUBY | ||
end | ||
|
||
it 'does not register an offense when using `[]` with semi-infinite range with negative int' do | ||
expect_no_offenses(<<~RUBY) | ||
array[..-2] | ||
array[-2..] | ||
RUBY | ||
end | ||
end | ||
end |