Newsletters: fix subscription options translations and persistent

[dlind1]

Fixes I18N-289

Proposed changes

• Switch to the user locale before retrieving subscription options, so that the defaults would be translated.
• Compare the subscription options with the translated defaults on save, to avoid saving a value in the database if no changes were made.

Does this pull request change what data or activity we track or use?

Testing instructions

• Create two test sites, switch your user locale to a popular not-English one, like Spanish, French, German or Japanese.
• On the first test site, go to /wp-admin/admin.php?page=jetpack-newsletter&p=%2F%3Ftab%3Dsettings, confirm that "Welcome email message" appears in English.
• Make the 'Save' button appear by cutting the text from the textarea, then pasting it back, save the message.
• Checkout the PR and sandbox public-api.
• On site two confirm that the Welcome message appears translated, try saving it in the same way as for the first site.
• Change your user locale to another non-English one.
• Refresh the pages and confirm that the message appears in English on the first site and in the new locale on the second site.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the fix/newsletter-subscription-options-persistence branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack fix/newsletter-subscription-options-persistence

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 1 file.

File	Coverage	Δ%	Δ Uncovered
projects/plugins/jetpack/json-endpoints/class.wpcom-json-api-site-settings-endpoint.php	436/900 (48.44%)	1.44%	4 💔

Full summary · PHP report · JS report

_{If appropriate, add one of these labels to override the failing coverage check: Covered by non-unit tests Use to ignore the Code coverage requirement check when E2Es or other non-unit tests cover the code Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR I don't care about code coverage for this PR Use this label to ignore the check for insufficient code coveage.}

[Copilot]

Pull request overview

This PR updates Jetpack’s WP.com JSON API site settings endpoint behavior for subscription_options so defaults are translated in the current user’s locale and unchanged defaults are not persisted (preventing locale “freezing” in the DB).

Changes:

• Read subscription_options under the current user locale when building the settings response.
• On POST, compare incoming subscription_options against the current value/defaults and persist only truly changed sub-keys.
• Add/adjust PHPUnit coverage for the new persistence/no-op behavior and falsy hide_free_tier handling.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
projects/plugins/jetpack/tests/php/json-api/WPCOM_JSON_API_Site_Settings_V1_4_Endpoint_Test.php	Adds POST regression tests ensuring unchanged defaults aren’t persisted and only edited sub-keys are stored.
projects/plugins/jetpack/json-endpoints/class.wpcom-json-api-site-settings-endpoint.php	Switches read path to user-locale retrieval and changes POST logic to ignore unchanged default values and store only diffs.
projects/plugins/jetpack/changelog/fix-newsletter-subscription-options-persistence	Adds a Jetpack changelog entry describing the user-facing bugfix.

Comments suppressed due to low confidence (2)

projects/plugins/jetpack/tests/php/json-api/WPCOM_JSON_API_Site_Settings_V1_4_Endpoint_Test.php:286

• This test installs a default_option_subscription_options filter via an anonymous closure but never removes it, which can affect later tests in the same run. Clean it up in a finally block to avoid cross-test contamination.

	public function test_post_subscription_options_ignores_unchanged_defaults() {
		$defaults = $this->register_subscription_options_default();

		$setting  = wp_json_encode( array( 'subscription_options' => $defaults ), JSON_UNESCAPED_SLASHES );
		$response = $this->make_post_request( $setting );

projects/plugins/jetpack/tests/php/json-api/WPCOM_JSON_API_Site_Settings_V1_4_Endpoint_Test.php:303

• Like the other new subscription_options tests, this leaves the default_option_subscription_options test filter installed after the test completes (and it can stack if called repeatedly). Add cleanup in a finally block so later tests aren’t influenced by the stubbed defaults.

	public function test_post_subscription_options_persists_only_changed_sub_keys() {
		$defaults = $this->register_subscription_options_default();

		$setting  = wp_json_encode(
			array( 'subscription_options' => array_merge( $defaults, array( 'welcome' => 'My own welcome' ) ) ),
			JSON_UNESCAPED_SLASHES
		);
		$response = $this->make_post_request( $setting );

[dlind1]

Follow-up: Atomic / self-hosted sites still get empty defaults

This fix only covers the WPCOM JSON API endpoint (/rest/v1.4/sites/{id}/settings). Atomic and self-hosted sites use the Jetpack v4 endpoint (/wp-json/jetpack/v4/settings) instead, which is unchanged here.

On v4, subscription_options is read via get_option( 'subscription_options', $default ) with a hardcoded empty-string default from the schema. Passing a default makes subscription_options_fallback() short-circuit (if ( $passed_default ) return $default;), so it returns empty strings for invitation/welcome/comment_follow rather than the real (translatable) defaults — worse than untranslated.

Knock-on effect on save: the settings UI rebuilds and posts the whole bag from those empty GET values, and v4's array_merge (with no change-detection) persists the empty strings over the real defaults.

So the "translate the defaults / don't persist unchanged defaults" goal isn't met on Atomic. Suggest extending the same read-in-user-locale + change-detection handling to the v4 endpoint (likely by dropping the empty-string schema default so the fallback fires).

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (2)

projects/plugins/jetpack/tests/php/json-api/WPCOM_JSON_API_Site_Settings_V1_4_Endpoint_Test.php:248

• register_subscription_options_default() adds a global default_option_subscription_options filter but never removes it. Because filters are global in the PHP process, this can leak into later tests and change get_option( 'subscription_options' ) behavior unexpectedly. Consider storing the callback so it can be removed in tear_down() (or removing it at the end of each test).

		add_filter(
			'default_option_subscription_options',
			static function ( $default_value, $option, $passed_default ) use ( $defaults ) {
				return $passed_default ? $default_value : $defaults;
			},
			10,
			3
		);

projects/plugins/jetpack/json-endpoints/class.wpcom-json-api-site-settings-endpoint.php:665

• get_subscription_options_in_user_locale() repeats the defaults+stored merge block twice (including calling the default_option_subscription_options filter and get_option() twice). This is redundant work and can introduce unexpected side effects if the filter is not idempotent; it should only run once.

		$subscription_options         = array_merge( $default_subscription_options, $stored_subscription_options );

		if ( $switched_locale ) {
			restore_previous_locale();
		}