Ticket #59599: 58599.2.diff

src/wp-includes/class-wp-scripts.php

@@ -281 +281 @@
                         $intended_strategy = '';
                 }
 
+                // If the script is in the header group, current output is the header, the intended strategy is `defer`, the
+                // actual strategy is not defer and all dependent scripts are in the footer - move this script to the footer.
+                if ( 'defer' === $intended_strategy && 'defer' !== $strategy && 0 === $this->groups[ $handle ] && 0 === $group ) {
+                        // Check that all depedencies are in the footer.
+                        $all_deps_in_footer = true;
+                        foreach ( $this->get_dependents( $handle ) as $dep ) {
+                                if ( isset( $this->groups[ $dep ] ) && 1 !== $this->groups[ $dep ] ) {
+                                        $all_deps_in_footer = false;
+                                        break;
+                                }
+                        }
+                        if ( $all_deps_in_footer ) {
+                                $this->in_footer[] = $handle;
+                                return false;
+                        }
+                }
+
                 if ( $conditional ) {
                         $cond_before = "<!--[if {$conditional}]>\n";
                         $cond_after  = "<![endif]-->\n";

tests/phpunit/tests/dependencies/scripts.php

@@ -3065 +3065 @@
         protected function add_html5_script_theme_support() {
                 add_theme_support( 'html5', array( 'script' ) );
         }
+
+        /**
+         * Test that a script is moved to the footer if it is made non deferrable, was in the header and
+         * all scripts that depend on it are in the footer.
+         *
+         * @ticket 58599
+         *
+         * @dataProvider data_provider_script_move_to_footer
+         *
+         * @param string $b_in_footer in_footer value for script B.
+         * @param string $expected    Expected output.
+         * @param bool   $expect_a_in_footer Is script A in the footer?
+         * @param bool   $expect_b_in_footer Is script B in the footer?
+         */
+        public function test_wp_scripts_move_to_footer( $b_in_footer, $expected, $expect_a_in_footer, $expect_b_in_footer ) {
+                // Script A uses strategy=>defer. Script B depends on script A and uses in_footer=>true.
+                wp_enqueue_script( 'script-a', 'script-a.js', array(), null, array( 'strategy' => 'defer' ) );
+                wp_enqueue_script( 'script-b', 'script-b.js', array( 'script-a' ), null, $b_in_footer );
+
+                // Run the header and footer capturing the output.
+                ob_start();
+                wp_scripts()->do_head_items();
+                wp_scripts()->do_footer_items();
+                $actual = ob_get_clean();
+
+                $this->assertEquals( $expected, $actual );
+                $this->assertEquals( $expect_a_in_footer, in_array( 'script-a', wp_scripts()->in_footer, true ) );
+                $this->assertEquals( $expect_b_in_footer, in_array( 'script-b', wp_scripts()->in_footer, true ) );
+        }
+
+        /**
+         * Data provider for test_wp_scripts_move_to_footer.
+         *
+         * @return array[] {
+         *     Array of arguments for test.
+         *
+         *     @type string $b_in_footer in_footer value for script B.
+         *     @type string $expected    Expected output.
+         * }
+         */
+        public function data_provider_script_move_to_footer() {
+                return array(
+
+                        'b in the footer, not deferred' => array(
+                                // Script B is in the footer, but not deferred.
+                                'b_in_footer'        => true,
+                                'expect'             => '<script type="text/javascript" src="http://script-a.js" id="script-a-js" data-wp-strategy="defer"></script>
+<script type="text/javascript" src="http://script-b.js" id="script-b-js"></script>
+',
+                                'expect_a_in_footer' => true,
+                                'expect_b_in_footer' => true,
+                        ),
+                        'b in header not deferred'      => array(
+                                'b_in_footer'        => false,
+                                'expect'             => '<script type="text/javascript" src="http://script-a.js" id="script-a-js" data-wp-strategy="defer"></script>
+<script type="text/javascript" src="http://script-b.js" id="script-b-js"></script>
+',
+                                'expect_a_in_footer' => false,
+                                'expect_b_in_footer' => false,
+                        ),
+                        'b in footer and deferred'      => array(
+                                'b_in_footer'        => array(
+                                        'strategy'  => 'defer',
+                                        'in_footer' => true,
+                                ),
+                                'expect'             => '<script type="text/javascript" src="http://script-a.js" id="script-a-js" defer="defer" data-wp-strategy="defer"></script>
+<script type="text/javascript" src="http://script-b.js" id="script-b-js" defer="defer" data-wp-strategy="defer"></script>
+',
+                                'expect_a_in_footer' => false,
+                                'expect_b_in_footer' => true,
+                        ),
+                        'b in header and deferred'      => array(
+                                'b_in_footer'        => array( 'strategy' => 'defer' ),
+                                'expect'             => '<script type="text/javascript" src="http://script-a.js" id="script-a-js" defer="defer" data-wp-strategy="defer"></script>
+<script type="text/javascript" src="http://script-b.js" id="script-b-js" defer="defer" data-wp-strategy="defer"></script>
+',
+                                'expect_a_in_footer' => false,
+                                'expect_b_in_footer' => false,
+                        ),
+                );
+        }
 }