rubocop/rubocop-performance

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An extension of RuboCop focused on code performance checks.

Stars: 743
Forks: 96
Open beginner issues: 0
Indexed issues: 58
Avg merge: 2d 2h
Merged PRs (30d): 3

Dominant language: Ruby
License: MIT
Last GitHub push: Sep 9, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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58 open issues indexed

ReverseEach autocorrect changes implicit method return value Open

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

rubocop/rubocop-performance#536 · Opened Aug 30, 2026
RedundantBlockCall misses shadowed block argument inside begin body Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

rubocop/rubocop-performance#534 · Opened Aug 30, 2026
DoubleStartEndWith unsafe autocorrect changes impure receiver evaluation Open

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

rubocop/rubocop-performance#535 · Opened Aug 30, 2026
New cop: Performance/ChainedHashMerge Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

rubocop/rubocop-performance#526 · 2 reactions · Opened Feb 25, 2026
Wrong nil case handling for .include? Open

Difficulty 3/5 1-2 days Newbie friendliness 40/100

rubocop/rubocop-performance#525 · 1 comment · Opened Feb 10, 2026
Performance/StringInclude doesn't consider assignment context Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

rubocop/rubocop-performance#519 · 4 comments · Opened Oct 8, 2025
Include unnecessary blocks in affix checks Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

rubocop/rubocop-performance#516 · Opened Sep 6, 2025
Request: Object Shape (ivar initialization order) check Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

rubocop/rubocop-performance#515 · 2 comments · Opened Aug 29, 2025
Rake task gives different results when `rails` is loaded Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#508 · Opened Aug 10, 2025
Cop idea: short-circuit logical expressions quickly by evaluating variables first Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rubocop/rubocop-performance#505 · Opened Jun 13, 2025
Improvement for `Performance/MapCompact` Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rubocop/rubocop-performance#497 · Opened Apr 26, 2025
Make `Performance/Sum` aware of arrays Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

rubocop/rubocop-performance#495 · Opened Mar 25, 2025
Regular running benchmarks for all the cops? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#491 · 1 comment · Opened Feb 24, 2025
Cop idea: combine chained `select` / `reject` calls Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rubocop/rubocop-performance#473 · 7 comments · Opened Oct 2, 2024
RedundantStringChars is unsafe for autocorrection when string is too short or empty Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

rubocop/rubocop-performance#471 · Opened Sep 23, 2024
Cop idea: prefer `a.chain(b)` over `a + b` when iterating Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#461 · 1 reaction · Opened Aug 30, 2024
Detect usages of `methods.include?` and suggest `respond_to?` instead Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#456 · 1 comment · Opened Aug 8, 2024
Extend `Performance/Sum` to support method calls Open

enhancement

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#455 · 2 reactions · Opened Jul 4, 2024
Spaceship operator (`<=>`) incorrectly displays rendered as ligature `<⇒` in docs Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rubocop/rubocop-performance#442 · Opened Feb 14, 2024
Autocorrection for Performance/ConstantRegexp is not working with pattern matching Open

bug weird ruby

Difficulty 3/5 1-2 days Newbie friendliness 35/100

rubocop/rubocop-performance#438 · 2 comments · Opened Jan 31, 2024
Cop idea: replace `list = list.select {...}` with `list.select! {...}` Open

feature request

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#432 · 2 comments · Opened Jan 10, 2024
Cop idea: prefer `<<` over `push` Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#431 · Opened Jan 10, 2024
Performance/StringIdentifierArgument for interpolated string doesn't seem to boost performance. Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

rubocop/rubocop-performance#426 · 2 comments · 2 reactions · Opened Dec 18, 2023
Improve the `Performance/RedundantEqualityComparisonBlock` cop Open

enhancement

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#424 · Opened Dec 15, 2023
Improve the `Performance/TimesMap` cop Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#422 · 1 comment · Opened Dec 10, 2023
The `Style/MapCompactWithConditionalBlock` cop must be executed before or instead of the `Performance/MapCompact` cop Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

rubocop/rubocop-performance#414 · 5 comments · Opened Dec 2, 2023
Cop idea: `Enumerable#each + push` vs `Enumerable#map` Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

rubocop/rubocop-performance#397 · 5 comments · Opened Nov 26, 2023
Cop idea: `Array#insert` vs `Array#unshift` Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#396 · 3 comments · Opened Nov 26, 2023
Cop idea: Native `Hash#slice` vs other slice implementations before native code Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#394 · 2 comments · Opened Nov 25, 2023
Make `Performance/RedundantMerge` aware of `Hash#update` (or create similar cop) Open

Difficulty 3/5 1-2 days Newbie friendliness 43/100

rubocop/rubocop-performance#393 · 2 comments · Opened Nov 25, 2023
Improve `Performance/RedundantSortBlock` cop Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#383 · Opened Nov 17, 2023
Improve `Performance/SortReverse` cop Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#382 · 1 comment · Opened Nov 11, 2023
Improve `Performance/StringReplacement` cop Open

Difficulty 3/5 1-2 days Newbie friendliness 58/100

rubocop/rubocop-performance#379 · 6 comments · Opened Nov 4, 2023
Edge case for StringReplacement: Use delete instead of gsub cop Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#377 · 1 comment · Opened Oct 8, 2023
Cop suggestion: `merge({ kv1 })` is faster than `merge(kv1)` on Ruby >= 2.7 Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#372 · Opened Sep 16, 2023
`Lint/Loop` is recommending bad performance Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

rubocop/rubocop-performance#362 · 5 comments · Opened Jul 4, 2023
Disable Performance/OpenStruct for Rubies >= 2.1 Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rubocop/rubocop-performance#361 · Opened Jun 12, 2023
Cop enforcing using map for search instead of arrays Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#356 · Opened May 6, 2023
Performance/RegexpMatch not safe for variables that may be numeric Open

Difficulty 3/5 1-2 days Newbie friendliness 52/100

rubocop/rubocop-performance#355 · 2 comments · Opened May 4, 2023
Improve suggesting Performance/RedundantMerge Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

rubocop/rubocop-performance#334 · Opened Jan 23, 2023
Only enable cops that actually improve performance Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#329 · 3 comments · Opened Jan 3, 2023
New cop to check for better string/array call chain ordering Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#327 · 2 comments · Opened Dec 30, 2022
New cop `Lint/PredicateMemoization` Open

Difficulty 3/5 1-2 days Newbie friendliness 50/100

rubocop/rubocop-performance#326 · 2 comments · Opened Dec 30, 2022
`defined?` vs `instance_variable_defined?`/`const_defined?`/etc Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#325 · Opened Dec 29, 2022
Checks suggestions Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

rubocop/rubocop-performance#323 · Opened Dec 19, 2022
Performance/BlockGivenWithExplicitBlock results in slowdown Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#300 · 1 comment · Opened Aug 24, 2022
Rubocop suggests using same casecmp code even with the logic flipped Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

rubocop/rubocop-performance#298 · Opened Jul 31, 2022
Cop idea: detect redundant calls to `#to_a` for literals with an enumerable method Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rubocop/rubocop-performance#286 · 1 comment · Opened Apr 10, 2022
Detect using a regex to perform a case insenstive compare and suggest casecmp? Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rubocop/rubocop-performance#203 · Opened Dec 22, 2020
Retire `Performance/ArraySemiInfiniteRangeSlice` cop Open

Difficulty 3/5 1-2 days Newbie friendliness 25/100

rubocop/rubocop-performance#198 · 5 comments · Opened Nov 23, 2020

rubocop/rubocop-performance

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