Add new Performance/UnfreezeString cop
#4586
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| # @example | ||
| # # bad | ||
| # "string".dup | ||
| # String.new |
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I think it would be good to add String.new("") to a bad case. It takes an empty string as an argument.
| # @example | ||
| # # bad | ||
| # "string".dup | ||
| # String.new |
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It seems like this isn't actually checked by the cop. 🙂
| module RuboCop | ||
| module Cop | ||
| module Performance | ||
| # In Ruby 2.3 or later, Use unary plus operator to unfreeze a string |
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"Use" with lowercase "u", since it's in the middle of a sentence. 😊
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| it 'registers an offense for a heredoc with `.dup`' do | ||
| expect_offense(<<-RUBY.strip_indent) | ||
| <<TEXT.dup |
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Hm. Where does the plus go here? 🤔
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Cool! Had no idea this worked. 🙂
| # @example | ||
| # # bad | ||
| # "string".dup | ||
| # String.new |
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Thanks!
I'll add String.new('') to bad case.
And I'll add checks for String.new, String.new('') and String.new('something').
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I added checks for |
In Ruby 2.3 or later, `String#+@` is available. This method unfreezes a string. ```ruby str = 'foo'.freeze p str.frozen? # => true p (+str).frozen? # => false ``` `String#dup` works similarly, but `+@` is faster than `dup`. See. https://gist.github.com/k0kubun/e3da77cae2c132badd386c96f2de5768 This cop recommends to use `+@` instead of `dup`.
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| def_node_matcher :string_new?, <<-PATTERN | ||
| { | ||
| (send (const nil :String) :new {str dstr}) |
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Good reminder that I should look at adding an "optional" operator. 😅
In Ruby 2.3 or later,
String#+@is available.This method unfreezes a string.
String#dupworks similarly, but+@is faster thandup.See. https://gist.github.com/k0kubun/e3da77cae2c132badd386c96f2de5768
This cop recommends to use
+@instead ofdup.Before submitting the PR make sure the following are checked:
[Fix #issue-number](if the related issue exists).master(if not - rebase it).rake spec) are passing.rake internal_investigation.and description in grammatically correct, complete sentences.
rake generate_cops_documentation(required only when you've added a new cop or changed the configuration/documentation of an existing cop).