Changeset 55850 for trunk/tests/phpunit/tests/formatting/wpTrimExcerpt.php

Timestamp:

05/23/2023 06:23:59 PM (22 months ago)

Author:

flixos90

Message:

Media: Fix lazy-loading bug by avoiding to modify content images when creating an excerpt.

The wp_filter_content_tags() function, which modifies image tags for example to optimize performance, is hooked into the the_content filter by default. When rendering an excerpt for a post that doesn't have a manually provided excerpt, the post content is used to generate the excerpt, handled by the wp_trim_excerpt() function.

Prior to this changeset, this led to wp_filter_content_tags() being called on the content when generating the excerpt, which is wasteful as all tags are stripped from the excerpt, and it furthermore could result in a lazy-loading bug when the post content contained images, as those images were being counted even though they would never be rendered as part of the excerpt.

This changeset fixes the bug and slightly improves performance for generating an excerpt by temporarily unhooking the wp_filter_content_tags() function from the the_content filter when using it to generate the excerpt.

Props costdev, flixos90, joemcgill, mukesh27, salvoaranzulla, spacedmonkey, thekt12, westonruter.
Fixes #56588.

File:

• trunk/tests/phpunit/tests/formatting/wpTrimExcerpt.php (modified) (1 diff)

trunk/tests/phpunit/tests/formatting/wpTrimExcerpt.php

@@ -93 +93 @@
         $this->assertSame( 'Post content', wp_trim_excerpt( false, $post ) );
     }
+
+    /**
+     * Tests that `wp_trim_excerpt()` unhooks `wp_filter_content_tags()` from 'the_content' filter.
+     *
+     * @ticket 56588
+     */
+    public function test_wp_trim_excerpt_unhooks_wp_filter_content_tags() {
+        $post = self::factory()->post->create();
+
+        /*
+         * Record that during 'the_content' filter run by wp_trim_excerpt() the
+         * wp_filter_content_tags() callback is not used.
+         */
+        $has_filter = true;
+        add_filter(
+            'the_content',
+            static function( $content ) use ( &$has_filter ) {
+                $has_filter = has_filter( 'the_content', 'wp_filter_content_tags' );
+                return $content;
+            }
+        );
+
+        wp_trim_excerpt( '', $post );
+
+        $this->assertFalse( $has_filter, 'wp_filter_content_tags() was not unhooked in wp_trim_excerpt()' );
+    }
+
+    /**
+     * Tests that `wp_trim_excerpt()` doesn't permanently unhook `wp_filter_content_tags()` from 'the_content' filter.
+     *
+     * @ticket 56588
+     */
+    public function test_wp_trim_excerpt_should_not_permanently_unhook_wp_filter_content_tags() {
+        $post = self::factory()->post->create();
+
+        wp_trim_excerpt( '', $post );
+
+        $this->assertSame( 10, has_filter( 'the_content', 'wp_filter_content_tags' ), 'wp_filter_content_tags() was not restored in wp_trim_excerpt()' );
+    }
+
+    /**
+     * Tests that `wp_trim_excerpt()` doesn't restore `wp_filter_content_tags()` if it was previously unhooked.
+     *
+     * @ticket 56588
+     */
+    public function test_wp_trim_excerpt_does_not_restore_wp_filter_content_tags_if_previously_unhooked() {
+        $post = self::factory()->post->create();
+
+        // Remove wp_filter_content_tags() from 'the_content' filter generally.
+        remove_filter( 'the_content', 'wp_filter_content_tags' );
+
+        wp_trim_excerpt( '', $post );
+
+        // Assert that the filter callback was not restored after running 'the_content'.
+        $this->assertFalse( has_filter( 'the_content', 'wp_filter_content_tags' ) );
+    }
 }