Add config to enable/disable backmerge to upcoming release

Author: samrat

app/libs/coordinators/finalize_release/almost_trunk.rb

@@ -14,7 +14,9 @@ def call
     else
       create_tag.then do
         create_and_merge_pr(working_branch).then do
-          create_and_merge_pr(train.upcoming_release.branch_name) if train.upcoming_release
+          if train.backmerge_to_upcoming_release? && train.upcoming_release
+            create_and_merge_pr(train.upcoming_release.branch_name)
+          end
         end
       end
     end

app/libs/triggers/patch_pull_request.rb

@@ -22,7 +22,7 @@ def initialize(release, commit)
   def call
     @pull_request.create_and_merge!
 
-    if train.upcoming_release && !bot_commit?
+    if train.upcoming_release && train.backmerge_to_upcoming_release? && !bot_commit?
       upcoming_release_pr = Triggers::PullRequest.new(
         release: release,
         new_pull_request: (commit.pull_requests.build(release:, phase: :ongoing) if commit.pull_requests.find_by(base_ref: train.upcoming_release.branch_name).blank?),

app/views/trains/_form.html.erb

@@ -222,6 +222,18 @@
                                                html_options: { disabled: train.backmerge_disabled? }) %>
     <% end %>
 
+    <%= f.with_advanced_section(heading: "Backmerge to Upcoming Release") do |section| %>
+      <% section.with_description do %>
+        When enabled, changes from the current release will be automatically merged into the upcoming release branch.
+        By default, changes are only merged into the working branch.
+      <% end %>
+
+      <%= render Form::SwitchComponent.new(form: section.F,
+                                               field_name: :backmerge_to_upcoming_release,
+                                               on_label: "Backmerge to upcoming release enabled",
+                                               off_label: "Backmerge to upcoming release disabled") %>
+    <% end %>
+
     <%= f.with_advanced_section(heading: "Auto-apply patch changes") do |section| %>
       <% section.with_description do %>
         Disable this if you want to manually apply the commits after the initial rollout has started.
@@ -291,6 +303,7 @@
                                                switch_data: { dependent_disable_target: "secondary", action: "dependent-disable#change" }) %>
     <% end %>
 
+
     <% f.with_action do %>
       <%= f.F.authz_submit (train.persisted? ? "Update" : "Create"), (train.persisted? ? "archive.svg" : "plus.svg"), disabled: @edit_not_allowed %>
     <% end %>

db/migrate/20250220152948_add_backmerge_to_upcoming_release_to_train.rb

@@ -0,0 +1,5 @@
+class AddBackmergeToUpcomingReleaseToTrain < ActiveRecord::Migration[7.2]
+  def change
+    add_column :trains, :backmerge_to_upcoming_release, :boolean, default: false
+  end
+end