Automatically create release pull requests

Author: deivid-rodriguez

POLICIES.md

@@ -69,9 +69,12 @@ Bundler:
 
 *   Confirm all PRs that you want backported are properly tagged with `rubygems:
     <type>` or `bundler: <type>` labels at GitHub.
-*   Run `rake prepare_release[<target_version>]`, create a PR and merge it
-    to the stable branch once CI passes.
-*   Switch to the stable branch and pull the PR just merged.
+*   Run `rake prepare_release[<target_version>]`. This will create a PR to the
+    stable branch with the backports included in the release, and proper
+    changelogs and version bumps. It will also create a PR to merge release
+    changelogs into master.
+*   Once CI passes, merge the release PR, switch to the stable branch and pull
+    the PR just merged.
 *   Release `bundler` with `(cd bundler && bin/rake release)`.
 *   Release `rubygems` with `rake release`.
 

util/release.rb

@@ -184,13 +184,32 @@ def prepare!
 
       return if @level == :minor_or_major
 
+      system("git", "push", exception: true)
+
+      gh_client.create_pull_request(
+        "rubygems/rubygems",
+        @base_branch,
+        @release_branch,
+        "Prepare RubyGems #{@rubygems.version} and Bundler #{@bundler.version}",
+        "It's release day!"
+      )
+
       system("git", "checkout", "-b", "cherry_pick_changelogs", "master", exception: true)
 
       begin
         system("git", "cherry-pick", bundler_changelog, rubygems_changelog, exception: true)
+        system("git", "push", exception: true)
       rescue StandardError
         system("git", "cherry-pick", "--abort")
         system("git", "branch", "-D", "cherry_pick_changelogs")
+      else
+        gh_client.create_pull_request(
+          "rubygems/rubygems",
+          "master",
+          "cherry_pick_changelogs",
+          "Changelogs for RubyGems #{@rubygems.version} and Bundler #{@bundler.version}",
+          "Cherry-picking change logs from future RubyGems #{@rubygems.version} and Bundler #{@bundler.version} into master."
+        )
       end
     rescue StandardError
       system("git", "checkout", initial_branch)