Rakefile in cutting_edge-0.2.1 vs Rakefile in cutting_edge-0.3

@@ -1,7 +1,8 @@
 require 'rubygems'
 require 'date'
+require 'tempfile'
 require 'rspec/core/rake_task'
 
 task :default => :rspec
 
 desc "Run specs."
@@ -24,10 +25,18 @@
 def version
   line = File.read("lib/#{name}.rb")[/^\s*VERSION\s*=\s*.*/]
   line.match(/.*VERSION\s*=\s*['"](.*)['"]/)[1]
 end
 
+def latest_changes_file
+  'LATEST_CHANGES.md'
+end
+
+def history_file
+  'HISTORY.md'
+end
+
 # assumes x.y.z all digit version
 def next_version
   # x.y.z
   v = version.split '.'
   # bump z
@@ -84,18 +93,19 @@
 #
 #############################################################################
 
 desc 'Create a release build and push to rubygems'
 task :release => :build do
-  unless `git branch` =~ /^\* master$/
-    puts "You must be on the master branch to release!"
+  unless `git branch` =~ /^\* main$/
+    puts "You must be on the main branch to release!"
     exit!
   end
+  Rake::Task[:changelog].execute
   sh "git commit --allow-empty -a -m 'Release #{version}'"
-  sh "git pull --rebase origin master"
+  sh "git pull --rebase origin main"
   sh "git tag v#{version}"
-  sh "git push origin master"
+  sh "git push origin main"
   sh "git push origin v#{version}"
   sh "gem push pkg/#{name}-#{version}.gem"
 end
 
 desc 'Publish to rubygems. Same as release'
@@ -150,5 +160,45 @@
   unless Dir['VERSION*'].empty?
     puts "A `VERSION` file at root level violates Gem best practices."
     exit!
   end
 end
+
+desc 'Build changelog'
+task :changelog do
+  [latest_changes_file, history_file].each do |f|
+    unless File.exists?(f)
+      puts "#{f} does not exist but is required to build a new release."
+      exit!
+    end
+  end
+
+  latest_changes = File.open(latest_changes_file)
+  version_pattern = "# #{version}"
+
+  if !`grep "#{version_pattern}" #{history_file}`.empty?
+    puts "#{version} is already described in #{history_file}"
+    exit!
+  end
+
+  begin
+    unless latest_changes.readline.chomp! =~ %r{#{version_pattern}}
+      puts "#{latest_changes_file} should begin with '#{version_pattern}'"
+      exit!
+    end
+  rescue EOFError
+    puts "#{latest_changes_file} is empty!"
+    exit!
+  end
+
+  body = latest_changes.read
+  body.scan(/\s*#\s+\d\.\d.*/) do |match|
+    puts "#{latest_changes_file} may not contain multiple markdown headers!"
+    exit!
+  end
+
+  temp = Tempfile.new
+  temp.puts("#{version_pattern} / #{date}\n#{body}\n")
+  temp.close
+  `cat #{history_file} >> #{temp.path}`
+  `cat #{temp.path} > #{history_file}`
+end
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