Prepare PL 3.8 Release

[felixarntz]

This issue is to track preparation of the upcoming 3.8.0 release up until publishing, which is due January 27, 2025.

• Create release/3.8.0 branch closer to the release date
• Finalize scope and punt unfinished pull requests to following release (Thursday, January 23, 2025)
• Bump versions in milestones according to the scope (Thursday, January 23, 2025)
• Smoke test (Friday, January 24, 2025)
• Prepare the release (Monday, January 27, 2025)

Note: The release would normally happen on Monday January 20, but due to a US holiday several folks from the team that handle the releases are out, which is why the release is postponed to the day after.

Update: Due the holiday and the fact that several milestones are not yet cleared, the release has been postponed to the following Monday.

[westonruter]

Release branch has been created: https://github.com/WordPress/performance/tree/release/3.8.0

[westonruter]

Preparation PR: #1827

[westonruter]

Performance Lab testing

• Add Site Health check for Cache-Control: no-store page response header which disables bfcache. (1807)

See #1825 for an issue I found which I've submitted a fix for in #1826. With that fix present, when no Cache-Control: no-store is present, I get the following test:

But when I add a plugin that does:

<?php
/**
 * Plugin Name: No-Store
 */

add_action(
	'send_headers',
	function () {
		header( 'Cache-Control: no-store' );
	}
);

Then I get as expected:

• Add Site Health test to verify that static assets are served with far-future expires. (1727)

Testing a site with LocalWP which does not have a far-future expires header results in the expected site health test:

• Enqueue scripts using plugins_url() instead of plugin_dir_url(). (1761)

The includes/admin/plugin-activate-ajax.js script is added to the Performance screen as expected.

[westonruter]

Modern Image Formats testing

• Switch to wp_content_img_tag filter for improved image handling. (1772)

Upon uploading an image, I was able to see AVIF file served on the frontend:

<figure class="wp-block-image size-large">
  <img
    fetchpriority="high"
    decoding="async"
    width="1024"
    height="668"
    src="http://localhost:10043/wp-content/uploads/2025/01/bison1-1024x668.avif"
    alt=""
    class="wp-image-10"
    srcset="
      http://localhost:10043/wp-content/uploads/2025/01/bison1-1024x668.avif  1024w,
      http://localhost:10043/wp-content/uploads/2025/01/bison1-300x196.avif    300w,
      http://localhost:10043/wp-content/uploads/2025/01/bison1-768x501.avif    768w,
      http://localhost:10043/wp-content/uploads/2025/01/bison1-1536x1002.avif 1536w,
      http://localhost:10043/wp-content/uploads/2025/01/bison1-2048x1336.avif 2048w
    "
    sizes="(max-width: 1024px) 100vw, 1024px"
  />
</figure>

[westonruter]

Speculative Loading testing

• Implement speculative loading considerations for safer behavior. (1784)

The speculationrules script is now omitted when logged-in. When logged-out, it is included and works as expected. When a link includes a query var, it is not speculatively loaded.

[westonruter]

Embed Optimizer testing

• Remove requirement for both mobile and desktop URL metrics to be collected for preconnect links to be added. (1764)

I added a YouTube video to the top of a post and visited the frontend on desktop to trigger collection of a URL Metric. Upon reloading, I then saw the page include the preconnect links just for desktop as expected:

<link data-od-added-tag rel="preconnect" href="https://i.ytimg.com/" media="(min-width: 783px)">
<link data-od-added-tag rel="preconnect" href="https://www.youtube.com/" media="(min-width: 783px)">

[westonruter]

Image Prioritizer testing

• Remove erroneous check for resource initiator type when considering whether to submit LCP background image. (1760)

I activated Twenty Thirteen and visited the homepage on desktop where the header (with a background-image) is the LCP element. This resulted in the expected lcpElementExternalBackgroundImage in the submitted URL Metric:

[westonruter]

Optimization Detective testing

• Omit element node index in XPaths up to children of BODY. (1790)
• Disambiguate XPaths for children of BODY with id, class, or role attributes. (1797)

With existing URL Metrics already collected which reference a YouTube embed at:

/*[1][self::HTML]/*[2][self::BODY]/*[1][self::DIV]/*[2][self::DIV]/*[1][self::DIV]/*[1][self::DIV]/*[1][self::ARTICLE]/*[2][self::DIV]/*[1][self::FIGURE]/*[1][self::DIV]

The optimizations still apply to add the preconnect link from #1796 (comment), even though the FIGURE now has the XPath:

/HTML/BODY/DIV[@id='page']/*[2][self::DIV]/*[1][self::DIV]/*[1][self::DIV]/*[1][self::ARTICLE]/*[2][self::DIV]/*[1][self::FIGURE]/*[1][self::DIV]

• Eliminate varying URL Metrics by logged-in state and discontinue disabling optimization by default for admins. (1788)

I visited a page while being logged-in as an administrator and a URL Metric was collected. Additionally, when looking at the collected URL Metrics there is now only one post type for a given URL whereas before there would be two, one for unauthenticated visitors and another for authenticated ones.

• Add site health check to detect blocked REST API and short-circuit optimization when unavailable. (1762)

On a LocalWP site which has loopback request support, the Site Health test shows the expected result:

When I activate the Disable WP REST API plugin, I get:

And the expected warning appears in the plugin list table:

Optimizations are disabled on the frontend when this is the case and WP_ENVIRONMENT_TYPE is not local.

• Allow extensions to opt in to using the web-vitals attribution build via the od_use_web_vitals_attribution_build filter. (1759)

When loading the page I see the non-attribution build of web-vitals loaded by default:

"webVitalsLibrarySrc":"http:\/\/localhost:10043\/wp-content\/plugins\/optimization-detective\/build\/web-vitals.js?ver=4.2.4"

When I activate a plugin that does this:

add_filter( 'od_use_web_vitals_attribution_build', '__return_true' );

Then the page output changes as expected:

"webVitalsLibrarySrc":"http:\/\/localhost:10043\/wp-content\/plugins\/optimization-detective\/build\/web-vitals-attribution.js?ver=4.2.4"

And URL Metrics are collected as expected.

• Skip visiting tags in the Admin Bar when optimizing a page. (1816)

While being logged-in and the Image Prioritizer plugin is active, I do not seen any items from the admin bar in the collected URL Metric:

{
    "url": "http://localhost:10043/modern-image/",
    "viewport": {
        "width": 3201,
        "height": 1632
    },
    "elements": [
        {
            "isLCP": false,
            "isLCPCandidate": false,
            "xpath": "/HTML/BODY/DIV[@id='page']/*[2][self::DIV]/*[1][self::DIV]/*[1][self::DIV]/*[1][self::ARTICLE]/*[2][self::DIV]/*[1][self::FIGURE]/*[1][self::IMG]",
            "intersectionRatio": 1,
            "intersectionRect": {
                "x": 1140.4166259765625,
                "y": 465.36456298828125,
                "width": 604.0103759765625,
                "height": 394.01040649414062,
                "top": 465.36456298828125,
                "right": 1744.427001953125,
                "bottom": 859.37496948242188,
                "left": 1140.4166259765625
            },
            "boundingClientRect": {
                "x": 1140.4166259765625,
                "y": 465.36456298828125,
                "width": 604.0103759765625,
                "height": 394.01040649414062,
                "top": 465.36456298828125,
                "right": 1744.427001953125,
                "bottom": 859.37496948242188,
                "left": 1140.4166259765625
            }
        }
    ],
    "lcpElementExternalBackgroundImage": {
        "url": "http://localhost:10043/wp-content/themes/twentythirteen/images/headers/circle.png",
        "tag": "HEADER",
        "id": "masthead",
        "class": "site-header"
    },
    "timestamp": 1737855427.484776,
    "uuid": "70296c9f-780a-4ba7-b7d7-f183def683a4",
    "etag": "461f62c29dd8c1b925a0ee5a2b14ce7b"
}

• Ensure optimization is performed in the wp-env local environment and log debug messages to console when disabled. (1822)

When accessing a search results page and I have WP_DEBUG enabled, I see the console include the expected message:

[Optimization Detective] Page is not optimized because od_can_optimize_response() returned false. This can be overridden with the od_can_optimize_response filter.

• Skip visiting any tags inside of NOSCRIPT elements. (1783)

I added a NOSCRIPT tag with a nested IMG tag to a Custom HTML block. This IMG did not get a data-od-xpath attribute added to it, while a previous IMG in an Image block did get the attribute as expected.

• Introduce OD_Tag_Visitor_Context::track_tag() method as alternative for returning true in tag visitor callback. (1821)

I installed the Intrinsic Dimensions plugin with the westonruter/od-intrinsic-dimensions#1 PR checked out that leverages track_tag and it resulted in the expected data being added to the VIDEO tag in the submitted URL Metric:

It also resulted in the expected attributes being added to the VIDEO tag:

<video
  data-od-added-height
  data-od-added-style
  data-od-added-width
  data-od-intrinsic-dimensions-src-hash="4fb7e0d643f1bf97dd7ac7ac4772a7cc"
  data-od-xpath="/HTML/BODY/DIV[@id='page']/*[2][self::DIV]/*[1][self::DIV]/*[1][self::DIV]/*[1][self::ARTICLE]/*[2][self::DIV]/*[1][self::FIGURE]/*[1][self::VIDEO]"
  height="1920"
  style="height: auto; width: 100%; aspect-ratio: 1080 / 1920"
  width="1080"
  controls
  src="http://localhost:10043/wp-content/uploads/2025/01/goat-18139442-hd_1080_1920_30fps.mp4"
></video>