[Tooling] Use Release Version from ReleasesV2 in Code Freeze (#16232)

Author: iangmaia

.buildkite/release-pipelines/start-code-freeze.yml

@@ -21,7 +21,7 @@ steps:
       bundle exec fastlane run configure_apply
 
       echo '--- :snowflake: Start Code Freeze'
-      bundle exec fastlane start_code_freeze skip_confirm:true
+      bundle exec fastlane start_code_freeze version:"${RELEASE_VERSION}" skip_confirm:true
     retry:
       manual:
         # If those jobs fail, one should always prefer re-triggering a new build from ReleaseV2 rather than retrying the individual job from Buildkite

fastlane/Fastfile

@@ -184,29 +184,46 @@ platform :ios do
 
   # This lane executes the steps planned on code freeze, creating a new release branch from the current trunk
   #
+  # @param [String] version (optional) The version to use for the new release version to code freeze for.
+  #                 Typically auto-provided by ReleasesV2. If nil, computes the new version based on current one.
   # @param [Boolean] skip_confirm (default: false) If set, will skip the confirmation prompt before running the rest of the lane
   #
   # @example Running the lane
   #          bundle exec fastlane start_code_freeze skip_confirm:true
   #
-  lane :start_code_freeze do |skip_confirm: false|
+  lane :start_code_freeze do |version: nil, skip_confirm: false|
     ensure_git_status_clean
 
     # Check out the up-to-date default branch, the designated starting point for the code freeze
     Fastlane::Helper::GitHelper.checkout_and_pull(DEFAULT_BRANCH)
 
+    # Use provided version from release tool, or fall back to computed version
+    computed_version = release_version_next
+    new_version = version || computed_version
+
+    # Warn if provided version differs from computed version
+    if version && version != computed_version
+      warning_message = <<~WARNING
+        ⚠️ Version mismatch: The explicitly-provided version was '#{version}' while new computed version would have been '#{computed_version}'.
+        If this is unexpected, you might want to investigate the discrepency.
+        Continuing with the explicitly-provided verison '#{version}'.
+      WARNING
+      UI.important(warning_message)
+      buildkite_annotate(style: 'warning', context: 'start-code-freeze-version-mismatch', message: warning_message) if is_ci
+    end
+
     UI.important <<-MESSAGE
 
       Code Freeze:
-      • New release branch from #{DEFAULT_BRANCH}: release/#{release_version_next}
+      • New release branch from #{DEFAULT_BRANCH}: release/#{new_version}
       • Current release version and build code: #{release_version_current} (#{build_code_current}).
-      • New release version and build code: #{release_version_next} (#{build_code_code_freeze}).
+      • New release version and build code: #{new_version} (#{build_code_code_freeze}).
 
     MESSAGE
     UI.user_error!("Terminating as requested. Don't forget to run the remainder of this automation manually.") unless skip_confirm || UI.confirm('Do you want to continue?')
 
     # Create the release branch
-    new_release_branch = "release/#{release_version_next}"
+    new_release_branch = "release/#{new_version}"
     ensure_branch_does_not_exist!(new_release_branch)
 
     UI.message('Creating release branch...')
@@ -222,8 +239,6 @@ platform :ios do
     commit_version_bump
     UI.success("Done! New Release Version: #{release_version_current}. New Build Code: #{build_code_current}")
 
-    new_version = release_version_current
-
     extract_release_notes_for_version(
       version: new_version,
       release_notes_file_path: RELEASE_NOTES_SOURCE_PATH,