From a1e0556bfe07e27b2295c15f6c77653f7f0a75c5 Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Sat, 7 Jan 2023 09:40:21 +0900
Subject: [PATCH] Update generated changelog filenames

Follow up https://github.com/rubocop/rubocop/pull/11385.
---
 tasks/changelog.rb | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/tasks/changelog.rb b/tasks/changelog.rb
index e446e5a30b..2773b1631e 100644
--- a/tasks/changelog.rb
+++ b/tasks/changelog.rb
@@ -58,10 +58,9 @@ def extract_id(body)
 
     def str_to_filename(str)
       str
-        .downcase
         .split
-        .each { |s| s.gsub!(/\W/, '') }
         .reject(&:empty?)
+        .map { |s| prettify(s) }
         .inject do |result, word|
           s = "#{result}_#{word}"
           return result if s.length > MAX_LENGTH
@@ -76,6 +75,21 @@ def github_user
 
       user
     end
+
+    private
+
+    def prettify(str)
+      str.gsub!(/\W/, '_')
+
+      # Separate word boundaries by `_`.
+      str.gsub!(/([A-Z]+)(?=[A-Z][a-z])|([a-z\d])(?=[A-Z])/) do
+        (Regexp.last_match(1) || Regexp.last_match(2)) << '_'
+      end
+
+      str.gsub!(/\A_+|_+\z/, '')
+      str.downcase!
+      str
+    end
   end
 
   def self.pending?