Add a daily translation-sync job (#23001)

* Add daily translation-sync job (Buildkite + fastlane)

New update_translations lane downloads the latest WordPress & Jetpack
translations from GlotPress and opens/refreshes a single rolling
translations/daily-update PR via release-toolkit's find_or_create_pull_request.
A new scheduled Buildkite pipeline runs it daily.

* Fix translation-sync git identity and use proper git helpers

- download-translations.sh: 'source use-bot-for-git' (like the release
  committing lanes) so the agent has a git identity/auth; drop configure_apply
  (not needed for translations).
- update_translations lane: use GitHelper.create_branch / point_to_same_commit?
  and push_to_git_remote instead of raw git sh calls, mirroring release.rb.

* Run translation-sync on mac-metal (where use-bot-for-git is available)

The job commits, pushes and opens a PR, which needs the bot git identity from
use-bot-for-git — only available on mac-metal agents, same as the release
code-freeze/finalize lanes. (android only builds, so release-builds.yml stays there.)

* Disable translation-sync failure notifications

Comment out the notify block; the channel is pre-set to #wpmobile for if/when
it is re-enabled.

* Prune orphaned translations as a separate commit in update_translations

After downloading, prune keys no longer in the source strings (main/res vs
main; jetpack/res vs main+jetpack) via android_prune_orphaned_translations and
commit it separately, so the PR shows exactly what was pruned vs downloaded.

* Send translation-sync failure notifications to the test Slack channel

Re-enable the notify block, routed to #test-wpmobile-slack-integration while this flow is validated, mirroring the beta-promotion pipeline. Moves to #wpmobile once it ships to real use.

* Align download-translations.sh with sibling command-script style

Use `#!/usr/bin/env bash` + `set -eu` (the more robust shebang recommended in review) and the `:rubygems: Setting up Gems` header, matching build-trunk-internal.sh, gather-beta-candidates.sh and promote-to-beta.sh.

* Update daily translation lane to warn against manual changes

Co-authored-by: Jeremy Massel <1123407+jkmassel@users.noreply.github.com>

* Update daily translation lane to abort if the branch can't be checked out

Co-authored-by: Jeremy Massel <1123407+jkmassel@users.noreply.github.com>

* Use modifier unless for checkout_and_pull guard (RuboCop Style/IfUnlessModifier)

---------

Co-authored-by: Jeremy Massel <1123407+jkmassel@users.noreply.github.com>

Author: oguzkocer

.buildkite/commands/download-translations.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -eu
+
+echo "--- :robot_face: Use bot for git operations"
+source use-bot-for-git
+
+echo "--- :rubygems: Setting up Gems"
+install_gems
+
+echo "--- :globe_with_meridians: Download translations and open/update the PR"
+bundle exec fastlane update_translations

.buildkite/schedules/download-translations.yml

@@ -0,0 +1,28 @@
+# yaml-language-server: $schema=https://raw.githubusercontent.com/buildkite/pipeline-schema/main/schema.json
+---
+
+# Runs on a daily schedule (configured in the Buildkite UI, ~06:00 UTC) to sync the latest
+# translations from GlotPress into a single rolling `translations/daily-update` PR.
+#
+# Runs on `mac-metal` (like the release code-freeze/finalize lanes) because this job commits,
+# pushes and opens a PR, which needs the bot git identity from `use-bot-for-git` — that command
+# is only available on those agents.
+
+agents:
+  queue: "mac-metal"
+
+steps:
+  - label: ":globe_with_meridians: Download Translations"
+    command: .buildkite/commands/download-translations.sh
+    plugins: [$CI_TOOLKIT]
+
+# Slack backstop for a failed sync — its unique value is failures that abort before the lane runs
+# (gems/secrets) and can't self-report. Channel intentionally stays the test channel while this flow
+# is validated (mirrors promote-beta.yml + the Fastfile `send_slack_message` default); moves to
+# #wpmobile once it ships to real use.
+notify:
+  - slack:
+      channels:
+        - "#test-wpmobile-slack-integration"
+      message: "Failed to sync translations from GlotPress."
+    if: build.state == "failed"

fastlane/lanes/localization.rb

@@ -375,6 +375,72 @@
     )
   end
 
+  TRANSLATIONS_SYNC_BRANCH = 'translations/daily-update'
+
+  #####################################################################################
+  # update_translations
+  # -----------------------------------------------------------------------------------
+  # Downloads the latest WordPress & Jetpack translations from GlotPress and opens (or
+  # refreshes) a single rolling Pull Request, so `trunk` stays continuously localized.
+  # Intended to run on a daily schedule.
+  #
+  # Each run resets `translations/daily-update` to `trunk` and re-downloads, so the PR
+  # always shows the complete current translation delta against `trunk` (no accumulation).
+  # If GlotPress has nothing new, no commit is made and the lane exits without a PR.
+  # -----------------------------------------------------------------------------------
+  # Usage:
+  # bundle exec fastlane update_translations
+  #####################################################################################
+  lane :update_translations do
+    # `checkout_and_pull` swallows git errors and only signals failure through its return value, so
+    # abort explicitly rather than silently building the sync branch from a stale/wrong `trunk`.
+    UI.user_error!("Could not check out and pull #{DEFAULT_BRANCH}; aborting translation sync.") unless Fastlane::Helper::GitHelper.checkout_and_pull(DEFAULT_BRANCH)
+
+    # Reset the rolling branch to the tip of `trunk` so each run produces a clean delta against it.
+    Fastlane::Helper::GitHelper.delete_local_branch_if_exists!(TRANSLATIONS_SYNC_BRANCH)
+    Fastlane::Helper::GitHelper.create_branch(TRANSLATIONS_SYNC_BRANCH, from: DEFAULT_BRANCH)
+
+    download_translations
+
+    # `download_translations` commits when GlotPress has updates; if nothing changed, HEAD still
+    # points at `trunk` and there is nothing to open a PR for.
+    if Fastlane::Helper::GitHelper.point_to_same_commit?(DEFAULT_BRANCH, 'HEAD')
+      UI.important('No new translations from GlotPress today; nothing to sync.')
+      next
+    end
+
+    # Prune translations whose key is no longer in the source strings (GlotPress can still serve them),
+    # which would otherwise fail Lint's `ExtraTranslation` check. Done as a separate commit on top of the
+    # download so the PR shows exactly what was pruned vs. what was downloaded.
+    main_res = File.join('WordPress', 'src', 'main', 'res')
+    jetpack_res = File.join('WordPress', 'src', 'jetpack', 'res')
+    android_prune_orphaned_translations(res_dir: main_res)
+    android_prune_orphaned_translations(
+      res_dir: jetpack_res,
+      additional_source_strings_paths: [File.join(main_res, 'values', 'strings.xml')]
+    )
+    Fastlane::Helper::GitHelper.commit(message: 'Prune orphaned translations', files: :all)
+
+    push_to_git_remote(remote_branch: TRANSLATIONS_SYNC_BRANCH, tags: false, force: true, set_upstream: true)
+
+    # `find_or_create_pull_request` resolves the GitHub token the standard way (GITHUB_TOKEN) and only
+    # opens a PR when none is already open; the force-push above already refreshed any existing one.
+    pr_url = find_or_create_pull_request(
+      repository: GITHUB_REPO,
+      title: 'Update translations',
+      body: <<~BODY,
+        Automated daily translation sync from GlotPress. Opened by the `download-translations` scheduled pipeline.
+
+        ⚠️ This branch is reset to `trunk` and force-pushed daily — do not push commits here;
+        they will be overwritten. Fix translations in GlotPress instead.
+      BODY
+      head: TRANSLATIONS_SYNC_BRANCH,
+      base: DEFAULT_BRANCH,
+      labels: ['Localization']
+    )
+    UI.success("Translations PR: #{pr_url}")
+  end
+
   # Updates the `.po` file at the given `po_path` using the content of the `sources` files,
   # interpolating `release_version` where appropriate.
   # Internally, this calls the `gp_update_metadata_source` release toolkit action and adds Git management to it.