From 86156af939e41bcfd216a380f5e324808ee7a42a Mon Sep 17 00:00:00 2001
From: Parker Finch <pfinch@panoramaed.com>
Date: Wed, 5 May 2021 08:00:23 -0400
Subject: [PATCH] [Fix #240] Disable `Performance/Casecmp` cop

This cop suggests an incorrect fix when code involves non-ASCII
characters. Disabling it by default makes this risky behavior opt-in
rather than opt-out.
---
 CHANGELOG.md                                  |  5 +++++
 config/default.yml                            |  2 +-
 docs/modules/ROOT/pages/cops_performance.adoc | 10 +++++++---
 lib/rubocop/cop/performance/casecmp.rb        |  8 ++++++--
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dbfd7b82d4..b05a1a725d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Changes
+
+* [#240](https://github.com/rubocop/rubocop-performance/issues/240): Retire `Performance/Casecmp` cop. ([@parkerfinch][])
+
 ## 1.11.2 (2021-05-05)
 
 ### Bug fixes
@@ -271,3 +275,4 @@
 [@dvandersluis]: https://github.com/dvandersluis
 [@ghiculescu]: https://github.com/ghiculescu
 [@mfbmina]: https://github.com/mfbmina
+[@parkerfinch]: https://github.com/parkerfinch
diff --git a/config/default.yml b/config/default.yml
index e617662bd4..8eea0f89d6 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -52,7 +52,7 @@ 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
+  Enabled: false
   Safe: false
   VersionAdded: '0.36'
 
diff --git a/docs/modules/ROOT/pages/cops_performance.adoc b/docs/modules/ROOT/pages/cops_performance.adoc
index 2baa95b47a..1f1fc40d16 100644
--- a/docs/modules/ROOT/pages/cops_performance.adoc
+++ b/docs/modules/ROOT/pages/cops_performance.adoc
@@ -283,7 +283,7 @@ end
 |===
 | Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
 
-| Enabled
+| Disabled
 | No
 | Yes (Unsafe)
 | 0.36
@@ -292,8 +292,12 @@ end
 
 This cop identifies places where a case-insensitive string comparison
 can better be implemented using `casecmp`.
-This cop is unsafe because `String#casecmp` and `String#casecmp?` behave
-differently when using Non-ASCII characters.
+
+This cop is disabled by default because `String#casecmp` only works with
+ASCII characters. See https://github.com/rubocop/rubocop/issues/9753.
+
+If you are working only with ASCII characters, then this cop can be
+safely enabled.
 
 === Examples
 
diff --git a/lib/rubocop/cop/performance/casecmp.rb b/lib/rubocop/cop/performance/casecmp.rb
index c981757c79..1c4a1223fb 100644
--- a/lib/rubocop/cop/performance/casecmp.rb
+++ b/lib/rubocop/cop/performance/casecmp.rb
@@ -5,8 +5,12 @@ module Cop
     module Performance
       # This cop identifies places where a case-insensitive string comparison
       # can better be implemented using `casecmp`.
-      # This cop is unsafe because `String#casecmp` and `String#casecmp?` behave
-      # differently when using Non-ASCII characters.
+      #
+      # This cop is disabled by default because `String#casecmp` only works with
+      # ASCII characters. See https://github.com/rubocop/rubocop/issues/9753.
+      #
+      # If you are working only with ASCII characters, then this cop can be
+      # safely enabled.
       #
       # @example
       #   # bad