Impl changelog_generator.rb

Author: sue445

_tools/changelog_generator/README.md

@@ -0,0 +1,15 @@
+# changelog_generator
+Generate changelog entry
+
+## Requirements
+* Ruby
+* git
+* [gh](https://github.com/cli/cli)
+
+## Usage
+```bash
+$ ruby changelog_generator.rb --help
+Usage: changelog_generagtor [options]
+        --before=BEFORE              Before tag or sha1 (default: latest tag)
+        --after=AFTER                After tag or sha1 (default: HEAD)
+```

_tools/changelog_generator/changelog_generator.rb

@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+require "optparse"
+require "json"
+
+# @return [String]
+def latest_tag
+  `git tag`.each_line.map(&:strip).max_by { |tag| Gem::Version.create(tag.delete_prefix("v")) }
+end
+
+# @param before [String]
+# @param after [String]
+# @return [Array<Integer>]
+def search_pr_numbers(before:, after:)
+  commits = `git rev-list --merges --right-only #{before}...#{after}`.each_line.map(&:strip)
+  commits.map do |commit|
+    commit_message = `git show -q #{commit}`
+    commit_message =~ /Merge pull request #([0-9]+)/
+    Regexp.last_match(1).to_i
+  end
+end
+
+before = nil
+after = nil
+
+opt = OptionParser.new
+opt.on("--before=BEFORE", "Before tag or sha1 (default: latest tag)") { |v| before = v }
+opt.on("--after=AFTER", "After tag or sha1 (default: HEAD)") { |v| after = v }
+
+opt.parse!(ARGV)
+
+before ||= latest_tag
+after ||= "HEAD"
+
+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}`)
+  pr["label_names"] = pr["labels"].map { |label| label["name"] }
+  pr
+end
+
+# @param prs [Array<Hash>]
+#
+# @return [String]
+def generate_category_changelog(prs)
+  lines = []
+  found_pr_numbers = []
+  prs = prs.dup
+
+  ["breaking change", "bug", "enhancement"].each do |label|
+    label_prs = prs.find_all { |pr| pr["label_names"].include?(label) }
+
+    next if label_prs.empty?
+
+    case label
+    when "breaking change"
+      lines << "### :bomb: Breaking changes"
+    when "bug"
+      lines << "### Bugfixes"
+    when "enhancement"
+      lines << "### New Features"
+    end
+
+    label_prs.each do |pr|
+      lines < generate_changelog_line(pr)
+      found_pr_numbers << pr["number"]
+    end
+
+    found_pr_numbers.push(*label_prs.map { |pr| pr["number"] })
+
+    prs.reject! { |pr| found_pr_numbers.include?(pr["number"]) }
+
+    lines << ""
+  end
+
+  other_prs = prs.reject do |pr|
+    found_pr_numbers.include?(pr["number"]) || pr["label_names"].include?("chore")
+  end
+
+  lines << "### Other changes"
+  other_prs.each do |pr|
+    lines << generate_changelog_line(pr)
+  end
+  found_pr_numbers.push(*other_prs.map { |pr| pr["number"] })
+  lines << ""
+
+  return "* No changes\n\n" if found_pr_numbers.empty?
+
+  "#{lines.join("\n")}\n"
+end
+
+# @param pr [Hash]
+#
+# @return [String]
+def generate_changelog_line(pr)
+  author = pr["author"]["login"].delete_prefix("app/")
+
+  "* #{pr["title"]} by @#{author} in #{pr["url"]}"
+end
+
+changelog_body = +""
+
+changelog_body << "## Go\n"
+go_prs = all_prs.find_all { |pr| pr["label_names"].include?("go") }
+changelog_body << generate_category_changelog(go_prs)
+
+changelog_body << "## Ruby\n"
+ruby_prs = all_prs.find_all { |pr| pr["label_names"].include?("ruby") }
+changelog_body << generate_category_changelog(ruby_prs)
+
+changelog_body << "## ruby_h_to_go\n"
+ruby_h_to_go_prs = all_prs.find_all { |pr| pr["label_names"].include?("ruby_h_to_go") }
+changelog_body << generate_category_changelog(ruby_h_to_go_prs)
+
+changelog_body << "## Other\n"
+other_prs = all_prs.reject { |pr| pr["label_names"].any? { |label| %w[go ruby ruby_h_to_go chore].include?(label) } }
+changelog_body << generate_category_changelog(other_prs)
+
+changelog_body << "**Full Changelog**: https://github.com/ruby-go-gem/go-gem-wrapper/compare/#{before}...#{after}"
+
+puts changelog_body