sync: add generic issue and pull request templates

.github/actions/sync/issue_bug.template.yml

@@ -0,0 +1,33 @@
+name: New issue for Reproducible Bug
+description: "If you're sure it's reproducible and not just your machine: submit an issue so we can investigate."
+type: "Bug"
+body:
+  - type: checkboxes
+    attributes:
+      label: Verification
+      description: Verify you've followed these steps. If you can't truthfully check these boxes, open a discussion at https://github.com/orgs/Homebrew/discussions instead.
+      options:
+        - label: I searched for similar issues at https://github.com/%<repository>s/issues and found no duplicates.
+          required: true
+        - label: I did not use AI/LLM to create this issue, or I disclosed the tool and model used; I will answer maintainer questions myself without AI/LLM.
+          required: true
+  - type: textarea
+    attributes:
+      label: What were you trying to do (and why)?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: What happened?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: What did you expect to happen?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Step-by-step reproduction instructions
+    validations:
+      required: true

.github/actions/sync/issue_config.template.yml

@@ -0,0 +1,6 @@
+blank_issues_enabled: false
+
+contact_links:
+  - name: Get help in GitHub Discussions
+    url: https://github.com/orgs/Homebrew/discussions
+    about: Have a question? Not sure if your issue affects everyone reproducibly? The quickest way to get help is on Homebrew's GitHub Discussions!

.github/actions/sync/pull_request.template.md

@@ -0,0 +1,17 @@
+-----
+
+<!-- Only tick a checkbox once you've done it; honesty keeps reviews smooth. -->
+<!-- Tick with [x] before creating, or click the boxes afterwards. -->
+
+- [ ] Have you checked for other open [Pull Requests](https://github.com/%<repository>s/pulls) for the same change?
+- [ ] Have you explained what your changes do and why you'd like them included?
+- [ ] Have you written new tests where it makes sense?
+- [ ] Have you successfully run this repository's tests and checks locally?
+
+-----
+
+- [ ] I did not use AI/LLM to create this PR, or I disclosed the tool/model below and reviewed its output; I did not attribute commits to AI and will answer maintainer questions and review comments myself without AI/LLM.
+
+<!-- If AI was used, explain below how it was used and how you verified the changes. Non-maintainers may only have one AI-assisted PR open at a time. See https://docs.brew.sh/Responsible-AI-Usage for guidance. -->
+
+-----

.github/actions/sync/shared-config.rb

@@ -63,6 +63,16 @@ def safe_system(*args)
 codeowners_header = "# This file is synced from the `.github` repository, do not modify it directly.\n"
 # GitHub uses the first of these that exists and ignores the others.
 codeowners_paths = [codeowners, "CODEOWNERS", "docs/CODEOWNERS"].freeze
+pull_request_template = ".github/PULL_REQUEST_TEMPLATE.md"
+template_sources = {
+  pull_request_template               => ".github/actions/sync/pull_request.template.md",
+  ".github/ISSUE_TEMPLATE/bug.yml"    => ".github/actions/sync/issue_bug.template.yml",
+  ".github/ISSUE_TEMPLATE/config.yml" => ".github/actions/sync/issue_config.template.yml",
+}.freeze
+# GitHub reads templates from any of these locations, case-insensitively.
+# It no longer reads single-file `ISSUE_TEMPLATE.md` issue templates, only `ISSUE_TEMPLATE/` directories.
+existing_pull_request_template = %r{\A(?:\.github/|docs/)?pull_request_template(?:\.\w+)?(?:/|\z)}i
+existing_issue_template = %r{\A(?:\.github/|docs/)?issue_template/}i
 vale_ini = ".vale.ini"
 dependabot_template_yaml = ".github/actions/sync/dependabot.template.yml"
 dependabot_yaml = ".github/dependabot.yml"
@@ -219,6 +229,12 @@ def safe_system(*args)
 
 tracked_files = out.split("\0")
 
+out, err, status = Open3.capture3("git", "-C", target_directory, "ls-files", "-z", "--others", "--exclude-standard")
+raise err unless status.success?
+
+# Local syncs can run on checkouts with uncommitted template changes, so look at the files that are actually there.
+working_tree_files = (tracked_files + out.split("\0")).select { |path| (target_directory_path/path).exist? }
+
 swift_manifests = ["Package.swift", "Package.resolved"].freeze
 licenses_enabled ||= tracked_files.any? { |path| swift_manifests.include?(File.basename(path)) }
 
@@ -238,6 +254,7 @@ def safe_system(*args)
   rubocop_yaml,
   coderabbit_config_ts,
   codeowners,
+  *template_sources.keys,
   dependabot_yaml,
   *license_check_paths,
   check_template_rb,
@@ -450,6 +467,23 @@ def safe_system(*args)
     next unless target_path.exist?
 
     git "-C", target_directory, "rm", path
+  when *template_sources.keys
+    # A template here would become the default for every repository without one, including unsynced ones.
+    next if repository_name == ".github"
+
+    # Install templates once and then leave them to the repository, like any template it already has.
+    contents = format(Pathname(template_sources.fetch(path)).read, repository: "Homebrew/#{repository_name}")
+    if path == pull_request_template
+      own_templates = working_tree_files.grep(existing_pull_request_template) - [path]
+      # GitHub prefers `.github/`, so remove an unedited synced template once the repository adds its own elsewhere.
+      FileUtils.rm_f target_path if own_templates.any? && target_path.file? && target_path.read == contents
+      next if own_templates.any?
+    elsif working_tree_files.any?(existing_issue_template)
+      next
+    end
+    next if target_path.exist?
+
+    target_path.write(contents)
   else
     next if path == target_path.to_s
 

.github/actions/sync/shared-config_spec.rb

@@ -47,6 +47,10 @@ def git(*args, directory: target)
     successful_command("git", "-C", directory.to_s, *args).chomp
   end
 
+  def tracked_templates(pattern)
+    git("ls-files").lines(chomp: true).grep(pattern)
+  end
+
   def commit_fixture(directory: target)
     git("add", "--all", directory:)
     git("commit", "--quiet", "--message", "Fixture", directory:)
@@ -162,6 +166,19 @@ def synced_contents(path)
     entries = own_codeowners.lines.reject { |line| line.include?("coderabbit*") }.join
     "#{entries}/.coderabbit*  @Homebrew/maintainers\n"
   end
+  let(:pull_request_template) { ".github/PULL_REQUEST_TEMPLATE.md" }
+  let(:expected_templates) do
+    {
+      pull_request_template               => "pull_request.template.md",
+      ".github/ISSUE_TEMPLATE/bug.yml"    => "issue_bug.template.yml",
+      ".github/ISSUE_TEMPLATE/config.yml" => "issue_config.template.yml",
+    }.transform_values do |source|
+      format((source_repository/".github/actions/sync/#{source}").read,
+             repository: "Homebrew/#{File.basename(repository)}")
+    end
+  end
+  let(:issue_templates) { expected_templates.keys - [pull_request_template] }
+  let(:own_template) { "- [ ] Have you run `make test`?\n" }
   let(:original_gemfile) { "source \"https://rubygems.org\"\n\nruby file: \".ruby-version\"\n\ngem \"rake\"\n" }
   let(:custom_gemfile) { "source \"https://rubygems.org\"\n\ngem \"rake\"\n" }
   let(:expected_gemfile) do
@@ -315,6 +332,130 @@ def synced_contents(path)
     end
   end
 
+  it "installs issue and pull request templates linking to the repository, repeatedly" do
+    commit_fixture
+    sync_target
+    expected_templates.each { |path, contents| expect((target/path).read).to eq(contents) }
+    expect((target/pull_request_template).read).to include("https://github.com/Homebrew/no-ruby/pulls")
+    expect((target/".github/ISSUE_TEMPLATE/bug.yml").read).to include("https://github.com/Homebrew/no-ruby/issues")
+    expect_idempotent_sync
+  end
+
+  it "keeps an installed template after the repository edits it" do
+    commit_fixture
+    sync_target
+    write pull_request_template, own_template
+    commit_fixture
+    expect_idempotent_sync
+    expect((target/pull_request_template).read).to eq(own_template)
+  end
+
+  it "removes an unedited pull request template once the repository adds its own elsewhere" do
+    commit_fixture
+    sync_target
+    write "PULL_REQUEST_TEMPLATE.md", own_template
+    commit_fixture
+    sync_target
+    expect(target/pull_request_template).not_to exist
+    expect(tracked_templates(/pull_request_template/i)).to eq(["PULL_REQUEST_TEMPLATE.md"])
+    expect_idempotent_sync
+  end
+
+  it "keeps the pull request template when the repository's own one is deleted but not committed" do
+    commit_fixture
+    sync_target
+    write "PULL_REQUEST_TEMPLATE.md", own_template
+    commit_fixture
+    FileUtils.rm target/"PULL_REQUEST_TEMPLATE.md"
+    sync_target
+    expect((target/pull_request_template).read).to eq(expected_templates.fetch(pull_request_template))
+  end
+
+  it "installs issue templates when the last one is deleted but not committed" do
+    write ".github/ISSUE_TEMPLATE/feature.yml", own_template
+    commit_fixture
+    FileUtils.rm target/".github/ISSUE_TEMPLATE/feature.yml"
+    sync_target
+    issue_templates.each do |issue_template|
+      expect((target/issue_template).read).to eq(expected_templates.fetch(issue_template))
+    end
+  end
+
+  {
+    ".github/PULL_REQUEST_TEMPLATE.md"   => /pull_request_template/i,
+    "PULL_REQUEST_TEMPLATE.md"           => /pull_request_template/i,
+    ".github/ISSUE_TEMPLATE/feature.yml" => /issue_template/i,
+  }.each do |path, pattern|
+    it "keeps an uncommitted #{path} without adding a shared template beside it" do
+      commit_fixture
+      write path, own_template
+      sync_target
+      expect((target/path).read).to eq(own_template)
+      expect(tracked_templates(pattern)).to eq([path])
+    end
+  end
+
+  %w[
+    .github/PULL_REQUEST_TEMPLATE.md
+    .github/pull_request_template.md
+    PULL_REQUEST_TEMPLATE.md
+    docs/pull_request_template.md
+    .github/PULL_REQUEST_TEMPLATE/bug_fix.md
+  ].each do |path|
+    it "keeps a repository's own pull request template at #{path} and installs issue templates" do
+      write path, own_template
+      commit_fixture
+      sync_target
+      expect((target/path).read).to eq(own_template)
+      expect(tracked_templates(/pull_request_template/i)).to eq([path])
+      issue_templates.each do |issue_template|
+        expect((target/issue_template).read).to eq(expected_templates.fetch(issue_template))
+      end
+    end
+  end
+
+  %w[
+    .github/ISSUE_TEMPLATE/feature.yml
+    .github/ISSUE_TEMPLATE/config.yml
+    ISSUE_TEMPLATE/bug.md
+    docs/ISSUE_TEMPLATE/bug.md
+  ].each do |path|
+    it "keeps a repository's own issue template at #{path} and installs the pull request template" do
+      write path, own_template
+      commit_fixture
+      sync_target
+      expect((target/path).read).to eq(own_template)
+      expect(tracked_templates(/issue_template/i)).to eq([path])
+      expect((target/pull_request_template).read).to eq(expected_templates.fetch(pull_request_template))
+    end
+  end
+
+  %w[
+    .github/issue_template.md
+    ISSUE_TEMPLATE.md
+    docs/ISSUE_TEMPLATE.md
+  ].each do |path|
+    it "installs issue templates alongside the retired single-file template at #{path}" do
+      write path, own_template
+      commit_fixture
+      sync_target
+      expect((target/path).read).to eq(own_template)
+      issue_templates.each do |issue_template|
+        expect((target/issue_template).read).to eq(expected_templates.fetch(issue_template))
+      end
+    end
+  end
+
+  context "with the .github repository" do
+    let(:repository) { "source/.github" }
+
+    it "does not install templates" do
+      commit_fixture
+      sync_target
+      expected_templates.each_key { |path| expect(target/path).not_to exist }
+    end
+  end
+
   %w[
     Package.swift
     Package.resolved