Create release on GitHub Actions

Author: sue445

.github/workflows/release.yml

@@ -0,0 +1,29 @@
+name: Create releases
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ruby
+          bundler-cache: true
+
+      - name: Generate changelog
+        run: |
+          bundle exec rake changelog[,${TAG_NAME}] > /tmp/changelog.md
+        env:
+          TAG_NAME: ${{ github.ref_name }}
+
+      - name: Release
+        uses: softprops/action-gh-release@v2
+        with:
+          body_path: /tmp/changelog.md

_tools/changelog_generator/changelog_generator.rb

@@ -4,8 +4,8 @@
 require "json"
 
 # @return [String]
-def latest_tag
-  `git tag`.each_line.map(&:strip).max_by { |tag| Gem::Version.create(tag.delete_prefix("v")) }
+def search_git_tags
+  `git tag`.each_line.map(&:strip).sort_by { |tag| Gem::Version.create(tag.delete_prefix("v")) }.reverse
 end
 
 # @param before [String]
@@ -29,9 +29,27 @@ def search_pr_numbers(before:, after:)
 
 opt.parse!(ARGV)
 
-before ||= latest_tag
 after ||= "HEAD"
 
+unless before
+  git_tags = search_git_tags
+
+  if after == "HEAD"
+    # Use latest tag
+    before = git_tags[0]
+  else
+    index = git_tags.index(after)
+    before =
+      if index
+        # Use 1 previous tag of index
+        git_tags[index + 1]
+      else
+        # Use latest tag
+        git_tags[0]
+      end
+  end
+end
+
 pr_numbers = search_pr_numbers(before:, after:)
 all_prs = pr_numbers.map do |pr_number|
   pr = JSON.parse(`gh pr view --json number,title,author,labels,url #{pr_number}`)