Gutenberg RTC: Support HTTP polling provider

[arthur791004]

Related DOTCOM-16238

Proposed changes:

• Support HTTP polling provider as we want to enable it for free sites and limit 2 collaborators

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

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

Testing instructions:

• Apply changes to your sandbox
• Add following filters to mu-plugins/0-sandbox.php

  add_filter( 'wpcom_is_gutenberg_rtc_enabled', '__return_true' );
  
  add_filter( 'wpcom_gutenberg_rtc_providers', function() {
    return [ 'http-polling' ];
  } );

• Go to edit a page/post
• Check the network request
• Ensure it polls /wp-sync/v1/sites/:site/updates endpoint

Changelog

• Generate changelog entries for this PR (using AI).

[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 (WordPress.com Site Helper), and enable the feat/gb-rtc-default-provider branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack-mu-wpcom-plugin feat/gb-rtc-default-provider

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]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ Add a "[Status]" label (In Progress, Needs Review, ...).
  
• ✅ Add testing instructions.
  
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• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

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Mu Wpcom plugin:

• Next scheduled release: WordPress.com Simple releases happen semi-continuously (PCYsg-Jjm-p2)

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

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Wpcomsh plugin:

• Next scheduled release: Atomic deploys happen twice daily on weekdays (p9o2xV-2EN-p2)

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

[Copilot]

Pull request overview

Adds support for using Gutenberg Real-Time Collaboration (RTC) with the default HTTP polling provider by avoiding injecting the Jetpack MU script when it would unnecessarily override Gutenberg’s default provider behavior.

Changes:

• Detect when the only configured RTC provider is http-polling and skip enqueuing/injecting the gutenberg-rtc asset + inline config in that case.

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 2 files.

File	Coverage	Δ%	Δ Uncovered
projects/packages/jetpack-mu-wpcom/src/utils.php	6/81 (7.41%)	-0.59%	6 💔
projects/packages/jetpack-mu-wpcom/src/features/gutenberg-rtc/gutenberg-rtc.php	41/45 (91.11%)	42.72%	-12 💚

Full summary · PHP report

_{Coverage check overridden by Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR .}

[Copilot]

Pull request overview

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

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[Copilot]

Pull request overview

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

Comments suppressed due to low confidence (1)

projects/packages/jetpack-mu-wpcom/src/features/gutenberg-rtc/gutenberg-rtc.php:65

• wpcom_enqueue_gutenberg_rtc_assets() computes $providers once, but then calls wpcom_get_gutenberg_rtc_providers() again when building the inline data. Since this runs filters, the second call can be inconsistent (or expensive) and makes behavior dependent on filter side effects. Reuse the already-computed $providers when encoding the inline script.

	$providers = wpcom_get_gutenberg_rtc_providers();

	// If HTTP polling (Gutenberg’s built-in default provider when this script isn’t enqueued)
	// is the only provider being used, then we don’t need to inject any assets since that’s
	// already the default behavior.
	if ( count( $providers ) === 1 && in_array( 'http-polling', $providers, true ) ) {
		return;
	}

	$handle = jetpack_mu_wpcom_enqueue_assets( 'gutenberg-rtc', array( 'js' ) );

	$data = wp_json_encode(
		array(
			'providers' => wpcom_get_gutenberg_rtc_providers(),
		),
		JSON_UNESCAPED_SLASHES | JSON_HEX_TAG | JSON_HEX_AMP

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[Copilot]

These enqueue-related tests can be order-dependent because the global script registry persists across tests. If another test enqueues jetpack-mu-wpcom-gutenberg-rtc first, test_wpcom_enqueue_gutenberg_rtc_assets_skips_http_polling_only() may fail even though the code is correct. Reset $wp_scripts (as other tests in this package do) or explicitly dequeue/deregister the script in tear_down() before asserting enqueue state.

[Copilot]

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

projects/packages/jetpack-mu-wpcom/tests/php/features/gutenberg-rtc/Gutenberg_RTC_Test.php:75

• Test isolation: storing/restoring $wp_scripts/$wp_styles without resetting them means any enqueued/registered scripts from a test can leak into later tests (the stored value is the same object reference). In this repo other tests explicitly reset the script registry (e.g. by setting $wp_scripts = null or creating a new WP_Scripts) to avoid flakiness. Consider resetting $wp_scripts/$wp_styles to a clean state in set_up (after saving originals), so each test starts with an empty registry, then restore originals in tear_down.

	public function set_up(): void {
		parent::set_up();
		global $wp_settings_fields, $wp_scripts, $wp_styles;
		$this->original_wp_settings_fields = $wp_settings_fields;
		$this->original_wp_scripts         = $wp_scripts;
		$this->original_wp_styles          = $wp_styles;
	}

	/**
	 * Clean up filters and restore global state after each test.
	 */
	public function tear_down(): void {
		global $wp_settings_fields, $wp_scripts, $wp_styles;
		$wp_settings_fields = $this->original_wp_settings_fields; // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
		$wp_scripts         = $this->original_wp_scripts; // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
		$wp_styles          = $this->original_wp_styles; // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
		remove_all_filters( 'wpcom_is_gutenberg_rtc_enabled' );
		remove_all_filters( 'wpcom_gutenberg_rtc_providers' );
		parent::tear_down();
	}

projects/packages/jetpack-mu-wpcom/src/features/gutenberg-rtc/gutenberg-rtc.php:65

• wpcom_enqueue_gutenberg_rtc_assets() calls wpcom_get_gutenberg_rtc_providers() twice (once into $providers and again when building the inline data). If provider resolution is filter-driven, calling it twice can be inconsistent and makes debugging harder. Reuse the already-computed $providers when building the JSON data.

	$providers = wpcom_get_gutenberg_rtc_providers();

	// If HTTP polling (Gutenberg’s built-in default provider when this script isn’t enqueued)
	// is the only provider being used, then we don’t need to inject any assets since that’s
	// already the default behavior.
	if ( count( $providers ) === 1 && in_array( 'http-polling', $providers, true ) ) {
		return;
	}

	$handle = jetpack_mu_wpcom_enqueue_assets( 'gutenberg-rtc', array( 'js' ) );

	$data = wp_json_encode(
		array(
			'providers' => wpcom_get_gutenberg_rtc_providers(),
		),
		JSON_UNESCAPED_SLASHES | JSON_HEX_TAG | JSON_HEX_AMP

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[Copilot]

PR description mentions "limit 2 collaborators", but this change set only adds an allowlist + enqueue behavior for the http-polling provider and doesn’t appear to implement any collaborator limit. If the limit is handled elsewhere, consider linking to it in the PR description; otherwise, either implement the limit here or adjust the description to match what this PR actually changes.