From 20917f9a45b577c5e7f064820e73c64f9c03f20f Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Wed, 22 Feb 2023 13:54:19 +0000
Subject: [PATCH 01/43] get_eligible_loading_strategy logic

---
 src/wp-includes/class-wp-scripts.php | 52 ++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 459eeb81cde58..566c20a25c41f 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -757,6 +757,58 @@ private function get_normalized_script_args( $handle, $args = array() ) {
 		return wp_parse_args( $args, $default_args );
 	}
 
+	/**
+	 * Helper function to check if a script has an `after` inline dependency.
+	 */
+	private function has_after_inline_dependency( $handle ) {
+		return false !== $this->get_data( $handle, 'after' );
+	}
+
+	/**
+	 * Helper function to check if a script has an `before` inline dependency.
+	 */
+	private function has_before_inline_dependency( $handle ) {
+		return false !== $this->get_data( $handle, 'before' );
+	}
+
+	/**
+	 * Get the correct loading strategy for the script.
+	 *
+	 * @param string  $handle Handle name of the script.
+	 * @return string $strategy return the final strategy.
+	 */
+	private function get_eligible_loading_strategy( $handle = '' ) {
+		if ( ! isset( $this->registered[ $handle ] ) ) {
+			return 'blocking';
+		}
+
+		$script_args = $this->get_data( $handle, 'script_args' );
+
+		if ( empty( $this->registered[ $handle ]->deps ) ) {
+			if ( ! isset( $script_args['strategy'] ) ) {
+				return 'async';
+			}
+
+			// Script eligible for async but user has specific strategy requirement.
+			return $script_args['strategy'];
+		}
+
+		$deps_has_async = false;
+		foreach ( $this->registered[ $handle ]->deps as $dep_handle ) {
+			$dep_strategy = $this->get_eligible_loading_strategy( $dep_handle );
+			if ( 'async' === $dep_strategy ) {
+				$deps_has_async = true;
+				break;
+			}
+		}
+
+		if ( ! $deps_has_async && ! $this->has_before_inline_dependency( $handle ) ) {
+			return 'defer';
+		}
+
+		return 'blocking';
+	}
+
 	/**
 	 * Resets class properties.
 	 *

From db02a89e1e370abcde2a6f95636b3f7abac3eccd Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Thu, 23 Feb 2023 14:50:21 +0000
Subject: [PATCH 02/43] Deferring strategy refined

---
 src/wp-includes/class-wp-scripts.php | 111 +++++++++++++++++++++------
 1 file changed, 86 insertions(+), 25 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 566c20a25c41f..76fabc7df22ec 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -746,10 +746,8 @@ public function add_data( $handle, $key, $value ) {
 	 * @return array        Normalized $args array.
 	 */
 	private function get_normalized_script_args( $handle, $args = array() ) {
-		$default_args = array(
-			'in_footer' => false,
-			'strategy'  => 'blocking',
-		);
+		$default_args = array( 'in_footer' => false );
+
 		// Handle backward compatibility for $in_footer.
 		if ( true === $args ) {
 			$args = array( 'in_footer' => true );
@@ -757,18 +755,82 @@ private function get_normalized_script_args( $handle, $args = array() ) {
 		return wp_parse_args( $args, $default_args );
 	}
 
+	/**
+	 * Get all of the scripts that depend on a script.
+	 *
+	 * @param string $handle The script handle.
+	 * @return array Array of script handles.
+	 */
+	private function get_dependents( $handle ) {
+		$dependents = array();
+
+		// Iterate over all registered scripts, finding ones that depend on the script.
+		foreach ( $this->registered as $registered_handle => $args ) {
+			if ( in_array( $handle, $args->deps, true ) ) {
+				$dependents[] = $registered_handle;
+			}
+		}
+		return $dependents;
+	}
+
+	/**
+	 * Get the strategy mentioned during script registration.
+	 *
+	 * @param string $handle The script handle.
+	 * @return string|bool Strategy in script registration, False if not strategy is mentioned..
+	 */
+	private function get_intended_strategy( $handle ) {
+		$script_args = $this->get_data( $handle, 'script_args' );
+		return isset( $script_args['strategy'] ) ? $script_args['strategy'] : false;
+	}
+
 	/**
 	 * Helper function to check if a script has an `after` inline dependency.
+	 *
+	 * @param string $handle Name of the item. Should be unique.
+	 * @return bool True on success, false on failure.
 	 */
 	private function has_after_inline_dependency( $handle ) {
 		return false !== $this->get_data( $handle, 'after' );
 	}
 
+
 	/**
-	 * Helper function to check if a script has an `before` inline dependency.
+	 * Check if all of a scripts dependents are deferrable which is required to maintain execution order.
+	 *
+	 * @param string $handle  The script handle.
+	 * @param array $visited An array of already visited script handles used to avoid looping recursion.
+	 * @return bool True if all dependents are deferrable, false otherwise.
 	 */
-	private function has_before_inline_dependency( $handle ) {
-		return false !== $this->get_data( $handle, 'before' );
+	private function all_dependents_are_deferrable( $handle, $visited = array() ) {
+		// If this node was already visited, this script can be deferred and the branch ends.
+		if ( in_array( $handle, $visited, true ) ) {
+			return true;
+		}
+		$visited[]  = $handle;
+		$dependents = $this->get_dependents( $handle );
+		// If there are no dependents remaining to consider, the script can be deferred and the branch ends.
+		if ( empty( $dependents ) ) {
+			return true;
+		}
+
+		// Consider each dependent and check if it is deferrable.
+		foreach ( $dependents as $dependent ) {
+			// If the dependent script is not using the defer strategy, no script in the chain is deferrable.
+			$script_args = $this->get_data( $handle, 'script_args' );
+			if ( empty( $script_args['strategy'] ) ) {
+				return false;
+			}
+			if ( 'defer' !== $script_args['strategy'] ) {
+				return false;
+			}
+
+			// Recursively check all dependent.
+			if ( ! $this->all_dependents_are_deferrable( $dependent, $visited ) ) {
+				return false;
+			}
+		}
+		return true;
 	}
 
 	/**
@@ -778,31 +840,30 @@ private function has_before_inline_dependency( $handle ) {
 	 * @return string $strategy return the final strategy.
 	 */
 	private function get_eligible_loading_strategy( $handle = '' ) {
-		if ( ! isset( $this->registered[ $handle ] ) ) {
+
+		$intended_strategy = $this->get_intended_strategy( $handle );
+		/**
+		 * Handle known blocking strategy scenarios.
+		 *
+		 * Blocking if not a registered handle.
+		 * If the script has an 'after' inline dependency, then it can't be eligible for async or defer.
+		 */
+		if ( ! isset( $this->registered[ $handle ] ) ||
+			$this->has_after_inline_dependency( $handle ) ||
+			'blocking' === $intended_strategy
+			) {
 			return 'blocking';
 		}
 
-		$script_args = $this->get_data( $handle, 'script_args' );
-
-		if ( empty( $this->registered[ $handle ]->deps ) ) {
-			if ( ! isset( $script_args['strategy'] ) ) {
+		// Handling async strategy scenarios.
+		if ( empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) ) {
+			if ( false !== $intended_strategy || 'async' === $intended_strategy ) {
 				return 'async';
 			}
-
-			// Script eligible for async but user has specific strategy requirement.
-			return $script_args['strategy'];
-		}
-
-		$deps_has_async = false;
-		foreach ( $this->registered[ $handle ]->deps as $dep_handle ) {
-			$dep_strategy = $this->get_eligible_loading_strategy( $dep_handle );
-			if ( 'async' === $dep_strategy ) {
-				$deps_has_async = true;
-				break;
-			}
 		}
 
-		if ( ! $deps_has_async && ! $this->has_before_inline_dependency( $handle ) ) {
+		// Handling defer strategy scenarios. Dependency will never be async. So only checking dependent.
+		if ( ! $this->all_dependents_are_deferrable( $handle ) ) {
 			return 'defer';
 		}
 

From af30f17fe9deb510b1d6af16de786dfdfc6bc526 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Thu, 23 Feb 2023 21:55:27 +0000
Subject: [PATCH 03/43] Bug fix

---
 src/wp-includes/class-wp-scripts.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 76fabc7df22ec..3d31ac673cc3e 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -862,8 +862,8 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			}
 		}
 
-		// Handling defer strategy scenarios. Dependency will never be async. So only checking dependent.
-		if ( ! $this->all_dependents_are_deferrable( $handle ) ) {
+		// Handling defer strategy scenarios. Dependency will never be set async. So only checking dependent.
+		if ( $this->all_dependents_are_deferrable( $handle ) ) {
 			return 'defer';
 		}
 

From 2ed92d31c157f9d291db92802cf8b5fc6a1bd703 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 01:44:00 +0000
Subject: [PATCH 04/43] removing a few lines with function

---
 src/wp-includes/class-wp-scripts.php | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 3d31ac673cc3e..7c8e294afcb8a 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -817,11 +817,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 		// Consider each dependent and check if it is deferrable.
 		foreach ( $dependents as $dependent ) {
 			// If the dependent script is not using the defer strategy, no script in the chain is deferrable.
-			$script_args = $this->get_data( $handle, 'script_args' );
-			if ( empty( $script_args['strategy'] ) ) {
-				return false;
-			}
-			if ( 'defer' !== $script_args['strategy'] ) {
+			if ( 'defer' !== get_intended_strategy( $dependent ) ) {
 				return false;
 			}
 

From 552d91aafd6651f7b240d200d0dbbf5856e3390d Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 01:49:39 +0000
Subject: [PATCH 05/43] removing default script strategy

---
 tests/phpunit/tests/dependencies/scripts.php | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 6e810588b6c0a..ae5f51939268b 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -102,20 +102,12 @@ public function test_old_and_new_in_footer_scripts() {
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;
 		$args = array(
-			'in_footer' => true,
-			'strategy'  => 'async',
+			'in_footer' => true
 		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
 		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
 
 		// Test defaults.
-		$expected_args = array(
-			'in_footer' => true,
-			'strategy'  => 'blocking',
-		);
-		wp_register_script( 'defaults-strategy', '/defaults.js', array(), null, array( 'in_footer' => true ) );
-		$this->assertSame( $expected_args, $wp_scripts->get_data( 'defaults-strategy', 'script_args' ) );
-
 		$expected_args = array(
 			'in_footer' => false,
 			'strategy'  => 'async',
@@ -131,12 +123,9 @@ public function test_get_normalized_script_args() {
 		$this->assertSame( false, $wp_scripts->get_data( 'defaults-no-args', 'script_args' ) );
 
 		// Test backward compatibility.
-		$args = array(
-			'in_footer' => true,
-			'strategy'  => 'blocking',
-		);
+		$expected_args = array( 'in_footer' => true );
 		wp_enqueue_script( 'footer-old', '/footer-async.js', array(), null, true );
-		$this->assertSame( $args, $wp_scripts->get_data( 'footer-old', 'script_args' ) );
+		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-old', 'script_args' ) );
 	}
 
 	/**

From 1eacd055657d35d1f5b2c655821c2e2a04ecf82c Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 02:35:59 +0000
Subject: [PATCH 06/43] do_item strategy support

---
 src/wp-includes/class-wp-scripts.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 7c8e294afcb8a..317c1a8ffc002 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -390,8 +390,12 @@ public function do_item( $handle, $group = false ) {
 			return true;
 		}
 
+		$strategy = $this->get_eligible_loading_strategy( $handle );
+		if( '' !== $strategy ) {
+			$strategy = ' '.$strategy;
+		}
 		$tag  = $translations . $cond_before . $before_handle;
-		$tag .= sprintf( "<script%s src='%s' id='%s-js'></script>\n", $this->type_attr, $src, esc_attr( $handle ) );
+		$tag .= sprintf( "<script%s src='%s' id='%s-js'%s></script>\n", $this->type_attr, $src, esc_attr( $handle ), $strategy );
 		$tag .= $after_handle . $cond_after;
 
 		/**
@@ -817,7 +821,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 		// Consider each dependent and check if it is deferrable.
 		foreach ( $dependents as $dependent ) {
 			// If the dependent script is not using the defer strategy, no script in the chain is deferrable.
-			if ( 'defer' !== get_intended_strategy( $dependent ) ) {
+			if ( 'defer' !== $this->get_intended_strategy( $dependent ) ) {
 				return false;
 			}
 

From 4542775c566f9170e850e98b2e7e052026c069db Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 09:56:21 +0000
Subject: [PATCH 07/43] bug fix

---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 7c8e294afcb8a..c89a55235d64e 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -817,7 +817,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 		// Consider each dependent and check if it is deferrable.
 		foreach ( $dependents as $dependent ) {
 			// If the dependent script is not using the defer strategy, no script in the chain is deferrable.
-			if ( 'defer' !== get_intended_strategy( $dependent ) ) {
+			if ( 'defer' !== $this->get_intended_strategy( $dependent ) ) {
 				return false;
 			}
 

From d89ab9af812b049a1292837cf0ae050b8c9de946 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 19:05:19 +0000
Subject: [PATCH 08/43] Strategy name update.

---
 src/wp-includes/class-wp-scripts.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 317c1a8ffc002..e24ef77ea7d7c 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -852,7 +852,7 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			$this->has_after_inline_dependency( $handle ) ||
 			'blocking' === $intended_strategy
 			) {
-			return 'blocking';
+			return '';
 		}
 
 		// Handling async strategy scenarios.
@@ -867,7 +867,7 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			return 'defer';
 		}
 
-		return 'blocking';
+		return '';
 	}
 
 	/**

From 4105504074ced86b7115d512aaa11a1bd2ba4314 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Fri, 24 Feb 2023 19:31:27 +0000
Subject: [PATCH 09/43] fixing bug

---
 src/wp-includes/class-wp-scripts.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index c89a55235d64e..3109ecfd5ed4c 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -848,12 +848,12 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			$this->has_after_inline_dependency( $handle ) ||
 			'blocking' === $intended_strategy
 			) {
-			return 'blocking';
+			return '';
 		}
 
 		// Handling async strategy scenarios.
 		if ( empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) ) {
-			if ( false !== $intended_strategy || 'async' === $intended_strategy ) {
+			if ( false === $intended_strategy || 'async' === $intended_strategy ) {
 				return 'async';
 			}
 		}
@@ -863,7 +863,7 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			return 'defer';
 		}
 
-		return 'blocking';
+		return '';
 	}
 
 	/**

From a9eef9ff2b3745ed130913d33a55c3b190914fcc Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:13:01 +0000
Subject: [PATCH 10/43] strategy test cases

---
 tests/phpunit/tests/dependencies/scripts.php | 98 ++++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index ae5f51939268b..68a009ec5d8cf 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -63,8 +63,106 @@ public function test_wp_enqueue_script() {
 		$this->assertSame( '', get_echo( 'wp_print_scripts' ) );
 	}
 
+
+	/**
+	 * Test loading strategy.
+	 * 
+	 * @ticket 99999
+	 */
+	public function test_loading_strategy() {
+		global $wp_scripts;
+
+		/**
+		 * Async strategy testing.
+		 */
+		// Valid Async cases.
+		// No dependents, No dependencies then async.
+		wp_enqueue_script( 'main-script-a1', '/main-script-a1.js', array(), null, array( 'strategy' => 'async' ) );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-a1.js' id='main-script-a1-js' async></script>\n";
+		$this->assertSame( $expected, $output );
+
+		// Invalid async cases.
+		// If any dependencies then it's not async. Since dependency is blocking(/defer) final strategy will be defer.
+		wp_enqueue_script( 'dependency-script-a2', '/dependency-script-a2.js', array(), null );
+		wp_enqueue_script( 'main-script-a2', '/main-script-a2.js', array( 'dependency-script-a2' ), null, array( 'strategy' => 'async' ) );
+		$output       = get_echo( 'wp_print_scripts' );
+		$not_expected = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' async></script>";
+		$expected     = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' defer></script>";
+		$this->assertStringNotContainsString( $not_expected, $output );
+		$this->assertStringContainsString( $expected, $output );
+
+		// If any dependent then it's not async. Since dependent is not set to defer the final strategy will be blocking.
+		wp_enqueue_script( 'main-script-a3', '/main-script-a3.js', array(), null, array( 'strategy' => 'async' ) );
+		wp_enqueue_script( 'dependent-script-a3', '/dependent-script-a3.js', array( 'main-script-a3' ), null );
+		$output       = get_echo( 'wp_print_scripts' );
+		$not_expected = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js' async></script>";
+		$expected     = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js'></script>";
+		$this->assertStringNotContainsString( $not_expected, $output );
+		$this->assertStringContainsString( $expected, $output );
+
+		/**
+		 * Defer strategy testing.
+		 */
+		// Valid Defer cases.
+		// No dependents, No dependencies and defer strategy.
+		wp_enqueue_script( 'main-script-d1', '/main-script-d1.js', array(), null, array( 'strategy' => 'defer' ) );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-d1.js' id='main-script-d1-js' defer></script>\n";
+		$this->assertSame( $expected, $output );
+
+		// Main script is defer and all dependencies are either defer/blocking.
+		wp_enqueue_script( 'dependency-script-d2-1', '/dependency-script-d2-1.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependency-script-d2-2', '/dependency-script-d2-2.js', array(), null, array( 'strategy' => 'blocking' ) );
+		wp_enqueue_script( 'dependency-script-d2-3', '/dependency-script-d2-3.js', array( 'dependency-script-d2-2' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'main-script-d2', '/main-script-d2.js', array( 'dependency-script-d2-1', 'dependency-script-d2-3' ), null, array( 'strategy' => 'defer' ) );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-d2.js' id='main-script-d2-js' defer></script>\n";
+		$this->assertStringContainsString( $expected, $output );
+
+		// Main script is defer and all dependent are defer.
+		wp_enqueue_script( 'main-script-d3', '/main-script-d3.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-1', '/dependent-script-d3-1.js', array( 'main-script-d3' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-2', '/dependent-script-d3-2.js', array( 'dependent-script-d3-1' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-3', '/dependent-script-d3-3.js', array( 'dependent-script-d3-2' ), null, array( 'strategy' => 'defer' ) );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-d3.js' id='main-script-d3-js' defer></script>\n";
+		$this->assertStringContainsString( $expected, $output );
+
+		// Invalid defer.
+		// Main script is defer and all dependent are not defer. Then main script will have blocking(or no) strategy.
+		wp_enqueue_script( 'main-script-d4', '/main-script-d4.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d4-1', '/dependent-script-d4-1.js', array( 'main-script-d4' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d4-2', '/dependent-script-d4-2.js', array( 'dependent-script-d4-1' ), null, array( 'strategy' => 'blocking' ) );
+		wp_enqueue_script( 'dependent-script-d4-3', '/dependent-script-d4-3.js', array( 'dependent-script-d4-2' ), null, array( 'strategy' => 'defer' ) );
+		$output       = get_echo( 'wp_print_scripts' );
+		$not_expected = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js' defer></script>\n";
+		$expected     = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js'></script>\n";
+		$this->assertStringNotContainsString( $not_expected, $output );
+		$this->assertStringContainsString( $expected, $output );
+
+		/**
+		 * Blocking(or no) strategy testing.
+		 */
+		// Valid Defer cases.
+		// args set as blocking.
+		wp_enqueue_script( 'main-script-b1', '/main-script-b1.js', array(), null, array( 'strategy' => 'blocking' ) );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-b1.js' id='main-script-b1-js'></script>\n";
+		$this->assertSame( $expected, $output );
+		
+		// strategy args not set.
+		wp_enqueue_script( 'main-script-b2', '/main-script-b2.js', array(), null, array() );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-b2.js' id='main-script-b2-js'></script>\n";
+		$this->assertSame( $expected, $output );
+
+	}
+
 	/**
 	 * Test old and new in_footer logic.
+	 * 
+	 * @ticket 99991
 	 */
 	public function test_old_and_new_in_footer_scripts() {
 		// Scripts in head.

From c2c1d0722e74ad7e1db8d1ced181f4693c0a7609 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:14:42 +0000
Subject: [PATCH 11/43] cs fixes

---
 tests/phpunit/tests/dependencies/scripts.php | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 68a009ec5d8cf..31f4f15f35881 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -66,12 +66,10 @@ public function test_wp_enqueue_script() {
 
 	/**
 	 * Test loading strategy.
-	 * 
+	 *
 	 * @ticket 99999
 	 */
 	public function test_loading_strategy() {
-		global $wp_scripts;
-
 		/**
 		 * Async strategy testing.
 		 */
@@ -150,19 +148,18 @@ public function test_loading_strategy() {
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='/main-script-b1.js' id='main-script-b1-js'></script>\n";
 		$this->assertSame( $expected, $output );
-		
+
 		// strategy args not set.
 		wp_enqueue_script( 'main-script-b2', '/main-script-b2.js', array(), null, array() );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='/main-script-b2.js' id='main-script-b2-js'></script>\n";
 		$this->assertSame( $expected, $output );
-
 	}
 
 	/**
 	 * Test old and new in_footer logic.
-	 * 
-	 * @ticket 99991
+	 *
+	 * @ticket 99999
 	 */
 	public function test_old_and_new_in_footer_scripts() {
 		// Scripts in head.
@@ -200,7 +197,7 @@ public function test_old_and_new_in_footer_scripts() {
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;
 		$args = array(
-			'in_footer' => true
+			'in_footer' => true,
 		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
 		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );

From 9eb3f891c804ff951aa57a0ed8cdfc01418be5bf Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:23:19 +0000
Subject: [PATCH 12/43] opt-in + remove blocking after dep

---
 src/wp-includes/class-wp-scripts.php | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 3109ecfd5ed4c..17e95af679d8f 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -746,8 +746,10 @@ public function add_data( $handle, $key, $value ) {
 	 * @return array        Normalized $args array.
 	 */
 	private function get_normalized_script_args( $handle, $args = array() ) {
-		$default_args = array( 'in_footer' => false );
-
+		$default_args = array(
+			'in_footer' => false,
+			'strategy'  => 'blocking',
+		);
 		// Handle backward compatibility for $in_footer.
 		if ( true === $args ) {
 			$args = array( 'in_footer' => true );
@@ -844,18 +846,13 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 		 * Blocking if not a registered handle.
 		 * If the script has an 'after' inline dependency, then it can't be eligible for async or defer.
 		 */
-		if ( ! isset( $this->registered[ $handle ] ) ||
-			$this->has_after_inline_dependency( $handle ) ||
-			'blocking' === $intended_strategy
-			) {
+		if ( ! isset( $this->registered[ $handle ] ) || 'blocking' === $intended_strategy ) {
 			return '';
 		}
 
 		// Handling async strategy scenarios.
-		if ( empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) ) {
-			if ( false === $intended_strategy || 'async' === $intended_strategy ) {
-				return 'async';
-			}
+		if ( empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) && 'async' === $intended_strategy ) {
+			return 'async';
 		}
 
 		// Handling defer strategy scenarios. Dependency will never be set async. So only checking dependent.

From 35279fc922ba4022ae6215cb3dd19ed7f6630211 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:26:22 +0000
Subject: [PATCH 13/43] complex condition towards end

---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 17e95af679d8f..7b5d83e87c037 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -851,7 +851,7 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 		}
 
 		// Handling async strategy scenarios.
-		if ( empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) && 'async' === $intended_strategy ) {
+		if ( 'async' === $intended_strategy && empty( $this->registered[ $handle ]->deps ) && empty( $this->get_dependents( $handle ) ) ) {
 			return 'async';
 		}
 

From 1de0f319040beb873a75f22758f1cdf273800984 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:35:53 +0000
Subject: [PATCH 14/43] if user not entered

---
 src/wp-includes/class-wp-scripts.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 7b5d83e87c037..b813cf1eff48f 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -843,10 +843,11 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 		/**
 		 * Handle known blocking strategy scenarios.
 		 *
-		 * Blocking if not a registered handle.
-		 * If the script has an 'after' inline dependency, then it can't be eligible for async or defer.
+		 * blocking if explicitly set.
+		 * blocking if strategy not set.
+		 * blocking if not a registered handle.
 		 */
-		if ( ! isset( $this->registered[ $handle ] ) || 'blocking' === $intended_strategy ) {
+		if ( ! isset( $this->registered[ $handle ] ) || 'blocking' === $intended_strategy || ! $intended_strategy ) {
 			return '';
 		}
 

From d5ebbc314825fcf8866cba154964c2df08b1ca02 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:36:46 +0000
Subject: [PATCH 15/43] place comment in order

---
 src/wp-includes/class-wp-scripts.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index b813cf1eff48f..ff4d87a674b1a 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -843,9 +843,9 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 		/**
 		 * Handle known blocking strategy scenarios.
 		 *
-		 * blocking if explicitly set.
-		 * blocking if strategy not set.
 		 * blocking if not a registered handle.
+		 * blocking if explicitly set.
+		 * blocking if script args not set.
 		 */
 		if ( ! isset( $this->registered[ $handle ] ) || 'blocking' === $intended_strategy || ! $intended_strategy ) {
 			return '';

From 5795b4c44bc17b3d86ae039cd4935399a8a43825 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:43:03 +0000
Subject: [PATCH 16/43] restore default values

---
 tests/phpunit/tests/dependencies/scripts.php | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 31f4f15f35881..601665e50167e 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -199,8 +199,12 @@ public function test_get_normalized_script_args() {
 		$args = array(
 			'in_footer' => true,
 		);
+		$expected_args = array(
+			'in_footer' => true,
+			'strategy'  => 'blocking'
+		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
-		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
+		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
 
 		// Test defaults.
 		$expected_args = array(
@@ -218,7 +222,10 @@ public function test_get_normalized_script_args() {
 		$this->assertSame( false, $wp_scripts->get_data( 'defaults-no-args', 'script_args' ) );
 
 		// Test backward compatibility.
-		$expected_args = array( 'in_footer' => true );
+		$expected_args = array(
+			'in_footer' => true,
+			'strategy'  => 'blocking'
+		);
 		wp_enqueue_script( 'footer-old', '/footer-async.js', array(), null, true );
 		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-old', 'script_args' ) );
 	}

From 0ebfaa531bbd1857f394c55243e6823dc0867b2f Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:43:58 +0000
Subject: [PATCH 17/43] phpcs fixes

---
 tests/phpunit/tests/dependencies/scripts.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 601665e50167e..0d9766caf3a01 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -196,12 +196,12 @@ public function test_old_and_new_in_footer_scripts() {
 	 */
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;
-		$args = array(
+		$args          = array(
 			'in_footer' => true,
 		);
 		$expected_args = array(
 			'in_footer' => true,
-			'strategy'  => 'blocking'
+			'strategy'  => 'blocking',
 		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
 		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
@@ -224,7 +224,7 @@ public function test_get_normalized_script_args() {
 		// Test backward compatibility.
 		$expected_args = array(
 			'in_footer' => true,
-			'strategy'  => 'blocking'
+			'strategy'  => 'blocking',
 		);
 		wp_enqueue_script( 'footer-old', '/footer-async.js', array(), null, true );
 		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-old', 'script_args' ) );

From f6b04839af0f099c3db37f1e5fc436ad42d673ca Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Sun, 26 Feb 2023 04:46:02 +0000
Subject: [PATCH 18/43] Update text

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index ff4d87a674b1a..b3651f8879dd6 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -779,7 +779,7 @@ private function get_dependents( $handle ) {
 	 * Get the strategy mentioned during script registration.
 	 *
 	 * @param string $handle The script handle.
-	 * @return string|bool Strategy in script registration, False if not strategy is mentioned..
+	 * @return string|bool Strategy set during script registration. False if none was set.
 	 */
 	private function get_intended_strategy( $handle ) {
 		$script_args = $this->get_data( $handle, 'script_args' );

From 7b36d211adb7c1bd41317fb276b0f84943fe6354 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Sun, 26 Feb 2023 04:47:54 +0000
Subject: [PATCH 19/43] Readability

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index b3651f8879dd6..1cc310d7114b0 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -811,6 +811,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 		}
 		$visited[]  = $handle;
 		$dependents = $this->get_dependents( $handle );
+
 		// If there are no dependents remaining to consider, the script can be deferred and the branch ends.
 		if ( empty( $dependents ) ) {
 			return true;

From f71319c71a93b0c43214a4e7451bd46e50ce058f Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Sun, 26 Feb 2023 04:48:15 +0000
Subject: [PATCH 20/43] consistent with other docblock descriptions

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 1cc310d7114b0..8d540110676e3 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -835,7 +835,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 	/**
 	 * Get the correct loading strategy for the script.
 	 *
-	 * @param string  $handle Handle name of the script.
+	 * @param string  $handle Name of the script.
 	 * @return string $strategy return the final strategy.
 	 */
 	private function get_eligible_loading_strategy( $handle = '' ) {

From 624e797159224a2b8316974c4457317acaec8c94 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Sun, 26 Feb 2023 04:53:54 +0000
Subject: [PATCH 21/43] casting the result

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 8d540110676e3..57e830127c668 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -793,7 +793,7 @@ private function get_intended_strategy( $handle ) {
 	 * @return bool True on success, false on failure.
 	 */
 	private function has_after_inline_dependency( $handle ) {
-		return false !== $this->get_data( $handle, 'after' );
+		return (bool) $this->get_data( $handle, 'after' );
 	}
 
 

From b7334b7b94680dff7f073607cd6e8050b90aa523 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Sun, 26 Feb 2023 04:57:52 +0000
Subject: [PATCH 22/43] wordpress coding standards

---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index ff4d87a674b1a..65dd51bcede80 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -840,7 +840,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 	private function get_eligible_loading_strategy( $handle = '' ) {
 
 		$intended_strategy = $this->get_intended_strategy( $handle );
-		/**
+		/*
 		 * Handle known blocking strategy scenarios.
 		 *
 		 * blocking if not a registered handle.

From 5305f1caf67e488d889069fe295c0cfe6d18525a Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:10:56 +0000
Subject: [PATCH 23/43] restore test case

---
 tests/phpunit/tests/dependencies/scripts.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index ae5f51939268b..be014dff0237f 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -102,7 +102,8 @@ public function test_old_and_new_in_footer_scripts() {
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;
 		$args = array(
-			'in_footer' => true
+			'in_footer' => true,
+			'strategy'  => 'async',
 		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
 		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
@@ -123,7 +124,10 @@ public function test_get_normalized_script_args() {
 		$this->assertSame( false, $wp_scripts->get_data( 'defaults-no-args', 'script_args' ) );
 
 		// Test backward compatibility.
-		$expected_args = array( 'in_footer' => true );
+		$expected_args = array(
+			'in_footer' => true,
+			'strategy'  => 'blocking',
+		);
 		wp_enqueue_script( 'footer-old', '/footer-async.js', array(), null, true );
 		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-old', 'script_args' ) );
 	}

From 073684a5d93b3869640f268fcc8f5de1d330841f Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:13:29 +0000
Subject: [PATCH 24/43] add temporary ticket id

---
 tests/phpunit/tests/dependencies/scripts.php | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index be014dff0237f..f9c51de6198a9 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -98,6 +98,8 @@ public function test_old_and_new_in_footer_scripts() {
 
 	/**
 	 * Test normalized script args.
+	 *
+	 * @ticket 99999
 	 */
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;

From 5e343b87c54b26ebffb3b89235919343072fa312 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:14:46 +0000
Subject: [PATCH 25/43] fix test bug

---
 tests/phpunit/tests/dependencies/scripts.php | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 0d9766caf3a01..6298edf224304 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -193,18 +193,17 @@ public function test_old_and_new_in_footer_scripts() {
 
 	/**
 	 * Test normalized script args.
+	 *
+	 * @ticket 99999
 	 */
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;
-		$args          = array(
+		$args = array(
 			'in_footer' => true,
-		);
-		$expected_args = array(
-			'in_footer' => true,
-			'strategy'  => 'blocking',
+			'strategy'  => 'async',
 		);
 		wp_enqueue_script( 'footer-async', '/footer-async.js', array(), null, $args );
-		$this->assertSame( $expected_args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
+		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
 
 		// Test defaults.
 		$expected_args = array(

From b56c0e1af3eb5c8ac595d5b0b7e91e91f7083bf8 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:18:47 +0000
Subject: [PATCH 26/43] restore test case

---
 tests/phpunit/tests/dependencies/scripts.php | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index f9c51de6198a9..c9a09b4a4f195 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -111,6 +111,13 @@ public function test_get_normalized_script_args() {
 		$this->assertSame( $args, $wp_scripts->get_data( 'footer-async', 'script_args' ) );
 
 		// Test defaults.
+		$expected_args = array(
+			'in_footer' => true,
+			'strategy'  => 'blocking',
+		);
+		wp_register_script( 'defaults-strategy', '/defaults.js', array(), null, array( 'in_footer' => true ) );
+		$this->assertSame( $expected_args, $wp_scripts->get_data( 'defaults-strategy', 'script_args' ) );
+
 		$expected_args = array(
 			'in_footer' => false,
 			'strategy'  => 'async',

From b70ee6c18282b3db2ef343507748d100604c7991 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:30:09 +0000
Subject: [PATCH 27/43] temporary ticket added for testing

---
 tests/phpunit/tests/dependencies/scripts.php | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index c9a09b4a4f195..7fc36739fa81b 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -65,6 +65,8 @@ public function test_wp_enqueue_script() {
 
 	/**
 	 * Test old and new in_footer logic.
+	 *
+	 * @ticket 99999
 	 */
 	public function test_old_and_new_in_footer_scripts() {
 		// Scripts in head.

From 2deadcf156a1d01eb8acf7bbbe205fa744a5dc7d Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:31:36 +0000
Subject: [PATCH 28/43] remove extra line

---
 tests/phpunit/tests/dependencies/scripts.php | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 40358e416b6c2..ec0cc0a2fa45a 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -63,7 +63,6 @@ public function test_wp_enqueue_script() {
 		$this->assertSame( '', get_echo( 'wp_print_scripts' ) );
 	}
 
-
 	/**
 	 * Test loading strategy.
 	 *

From fcaa62e27d13405710155ff3ffdbc60179063788 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 09:57:35 +0000
Subject: [PATCH 29/43] remove after dependency function

---
 src/wp-includes/class-wp-scripts.php | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 951658fe001ee..16d3c6356d7a0 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -786,17 +786,6 @@ private function get_intended_strategy( $handle ) {
 		return isset( $script_args['strategy'] ) ? $script_args['strategy'] : false;
 	}
 
-	/**
-	 * Helper function to check if a script has an `after` inline dependency.
-	 *
-	 * @param string $handle Name of the item. Should be unique.
-	 * @return bool True on success, false on failure.
-	 */
-	private function has_after_inline_dependency( $handle ) {
-		return (bool) $this->get_data( $handle, 'after' );
-	}
-
-
 	/**
 	 * Check if all of a scripts dependents are deferrable which is required to maintain execution order.
 	 *

From d578e50a511c6d5fdf3ed8dcf4b159ded10c2d79 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Mon, 27 Feb 2023 18:31:41 +0000
Subject: [PATCH 30/43] fix doc block text

Co-authored-by: Simon Dowdles <72872375+10upsimon@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 16d3c6356d7a0..c724615a2266e 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -822,7 +822,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 	}
 
 	/**
-	 * Get the correct loading strategy for the script.
+	 * Get the most eligible loading strategy for a script.
 	 *
 	 * @param string  $handle Name of the script.
 	 * @return string $strategy return the final strategy.

From 5262bf78f6a25f373ef1b5670d7ec1f98811f00e Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Mon, 27 Feb 2023 18:34:04 +0000
Subject: [PATCH 31/43] Correct grammar

Co-authored-by: Simon Dowdles <72872375+10upsimon@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index c724615a2266e..6f2a7bc0e3a19 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -813,7 +813,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 				return false;
 			}
 
-			// Recursively check all dependent.
+			// Recursively check all dependents.
 			if ( ! $this->all_dependents_are_deferrable( $dependent, $visited ) ) {
 				return false;
 			}

From 2970f1a195b8e39ba4cb2e4b31d66b4ca2a858f1 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Mon, 27 Feb 2023 18:34:39 +0000
Subject: [PATCH 32/43] Fix doc block string.

Co-authored-by: Simon Dowdles <72872375+10upsimon@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 6f2a7bc0e3a19..70b44ab21ba62 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -824,7 +824,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 	/**
 	 * Get the most eligible loading strategy for a script.
 	 *
-	 * @param string  $handle Name of the script.
+	 * @param string  $handle The registered handle of the script.
 	 * @return string $strategy return the final strategy.
 	 */
 	private function get_eligible_loading_strategy( $handle = '' ) {

From 28af60db70410081bf8220eb6ca4149c889d146e Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 18:40:25 +0000
Subject: [PATCH 33/43] change variable name

---
 src/wp-includes/class-wp-scripts.php | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 70b44ab21ba62..d8bad6b4b2914 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -790,15 +790,15 @@ private function get_intended_strategy( $handle ) {
 	 * Check if all of a scripts dependents are deferrable which is required to maintain execution order.
 	 *
 	 * @param string $handle  The script handle.
-	 * @param array $visited An array of already visited script handles used to avoid looping recursion.
+	 * @param array $checked An array of already checked script handles, used to avoid looping recursion.
 	 * @return bool True if all dependents are deferrable, false otherwise.
 	 */
-	private function all_dependents_are_deferrable( $handle, $visited = array() ) {
-		// If this node was already visited, this script can be deferred and the branch ends.
-		if ( in_array( $handle, $visited, true ) ) {
+	private function all_dependents_are_deferrable( $handle, $checked = array() ) {
+		// If this node was already checked, this script can be deferred and the branch ends.
+		if ( in_array( $handle, $checked, true ) ) {
 			return true;
 		}
-		$visited[]  = $handle;
+		$checked[]  = $handle;
 		$dependents = $this->get_dependents( $handle );
 
 		// If there are no dependents remaining to consider, the script can be deferred and the branch ends.
@@ -814,7 +814,7 @@ private function all_dependents_are_deferrable( $handle, $visited = array() ) {
 			}
 
 			// Recursively check all dependents.
-			if ( ! $this->all_dependents_are_deferrable( $dependent, $visited ) ) {
+			if ( ! $this->all_dependents_are_deferrable( $dependent, $checked ) ) {
 				return false;
 			}
 		}

From f746dfdb8a8d404cab0a2f5c963a4a44874e23df Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Mon, 27 Feb 2023 18:52:52 +0000
Subject: [PATCH 34/43] doc block changes, better word

---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index d8bad6b4b2914..8ca9498494538 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -776,7 +776,7 @@ private function get_dependents( $handle ) {
 	}
 
 	/**
-	 * Get the strategy mentioned during script registration.
+	 * Get the strategy assigned during script registration.
 	 *
 	 * @param string $handle The script handle.
 	 * @return string|bool Strategy set during script registration. False if none was set.

From d4bbaff684e5019007ec1c09f14aee1947ace851 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Mon, 27 Feb 2023 19:11:34 +0000
Subject: [PATCH 35/43] spacing issue.

Co-authored-by: Simon Dowdles <72872375+10upsimon@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index e73ee878cf9c7..6623adc4d4fa3 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -392,7 +392,7 @@ public function do_item( $handle, $group = false ) {
 
 		$strategy = $this->get_eligible_loading_strategy( $handle );
 		if( '' !== $strategy ) {
-			$strategy = ' '.$strategy;
+			$strategy = ' ' . $strategy;
 		}
 		$tag  = $translations . $cond_before . $before_handle;
 		$tag .= sprintf( "<script%s src='%s' id='%s-js'%s></script>\n", $this->type_attr, $src, esc_attr( $handle ), $strategy );

From 01e1d4fd15139c5926c6515991fda6e933e80588 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <30643833+kt-12@users.noreply.github.com>
Date: Tue, 28 Feb 2023 12:55:58 +0000
Subject: [PATCH 36/43] update placeholder with numbered placeholder

Co-authored-by: Joe McGill <801097+joemcgill@users.noreply.github.com>
---
 src/wp-includes/class-wp-scripts.php | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 6623adc4d4fa3..28af51c80c720 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -395,7 +395,13 @@ public function do_item( $handle, $group = false ) {
 			$strategy = ' ' . $strategy;
 		}
 		$tag  = $translations . $cond_before . $before_handle;
-		$tag .= sprintf( "<script%s src='%s' id='%s-js'%s></script>\n", $this->type_attr, $src, esc_attr( $handle ), $strategy );
+		$tag .= sprintf( 
+			"<script%1$s src='%2$s' id='%3$s-js'%4$s></script>\n",
+			$this->type_attr,
+			esc_url($src),
+			esc_attr( $handle ),
+			$strategy
+		);
 		$tag .= $after_handle . $cond_after;
 
 		/**

From a36795164d4c4b9b0d0de091fdcc26a531b9f5d3 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 13:57:18 +0000
Subject: [PATCH 37/43] Change ticket id to trac id

---
 tests/phpunit/tests/dependencies/scripts.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index ec0cc0a2fa45a..2ea26a67f4b29 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -66,7 +66,7 @@ public function test_wp_enqueue_script() {
 	/**
 	 * Test loading strategy.
 	 *
-	 * @ticket 99999
+	 * @ticket 12009
 	 */
 	public function test_loading_strategy() {
 		/**
@@ -158,7 +158,7 @@ public function test_loading_strategy() {
 	/**
 	 * Test old and new in_footer logic.
 	 *
-	 * @ticket 99999
+	 * @ticket 12009
 	 */
 	public function test_old_and_new_in_footer_scripts() {
 		// Scripts in head.
@@ -193,7 +193,7 @@ public function test_old_and_new_in_footer_scripts() {
 	/**
 	 * Test normalized script args.
 	 *
-	 * @ticket 99999
+	 * @ticket 12009
 	 */
 	public function test_get_normalized_script_args() {
 		global $wp_scripts;

From 51e3e416214bde1084692c2197c5e4bfe762934d Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 13:59:06 +0000
Subject: [PATCH 38/43] Switching from numbered to normal substitution

---
 src/wp-includes/class-wp-scripts.php | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 28af51c80c720..0d30a3bac1b51 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -392,15 +392,15 @@ public function do_item( $handle, $group = false ) {
 
 		$strategy = $this->get_eligible_loading_strategy( $handle );
 		if( '' !== $strategy ) {
-			$strategy = ' ' . $strategy;
+			$strategy = ' '.$strategy;
 		}
 		$tag  = $translations . $cond_before . $before_handle;
 		$tag .= sprintf( 
-			"<script%1$s src='%2$s' id='%3$s-js'%4$s></script>\n",
-			$this->type_attr,
-			esc_url($src),
-			esc_attr( $handle ),
-			$strategy
+			"<script%s src='%s' id='%s-js'%s></script>\n", 
+			$this->type_attr, 
+			esc_url( $src ), 
+			esc_attr( $handle ), 
+			$strategy 
 		);
 		$tag .= $after_handle . $cond_after;
 

From 62cbf6079be3d9aa44d7e69ef597a51d49c9ec05 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 14:51:05 +0000
Subject: [PATCH 39/43] Breaking test into multiple test functions

---
 tests/phpunit/tests/dependencies/scripts.php | 53 +++++++++++---------
 1 file changed, 30 insertions(+), 23 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 2ea26a67f4b29..dd9bd4aff8a83 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -64,44 +64,45 @@ public function test_wp_enqueue_script() {
 	}
 
 	/**
-	 * Test loading strategy.
+	 * Test valid async loading strategy case.
 	 *
 	 * @ticket 12009
 	 */
-	public function test_loading_strategy() {
-		/**
-		 * Async strategy testing.
-		 */
-		// Valid Async cases.
+	public function test_loading_strategy_with_valid_async_registration() {
 		// No dependents, No dependencies then async.
 		wp_enqueue_script( 'main-script-a1', '/main-script-a1.js', array(), null, array( 'strategy' => 'async' ) );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='/main-script-a1.js' id='main-script-a1-js' async></script>\n";
 		$this->assertSame( $expected, $output );
+	}
 
-		// Invalid async cases.
+	/**
+	 * Test invalid async loading strategy cases.
+	 *
+	 * @ticket 12009
+	 */
+	public function test_loading_strategy_with_invalid_async_registration() {
 		// If any dependencies then it's not async. Since dependency is blocking(/defer) final strategy will be defer.
 		wp_enqueue_script( 'dependency-script-a2', '/dependency-script-a2.js', array(), null );
 		wp_enqueue_script( 'main-script-a2', '/main-script-a2.js', array( 'dependency-script-a2' ), null, array( 'strategy' => 'async' ) );
 		$output       = get_echo( 'wp_print_scripts' );
-		$not_expected = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' async></script>";
 		$expected     = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' defer></script>";
-		$this->assertStringNotContainsString( $not_expected, $output );
 		$this->assertStringContainsString( $expected, $output );
 
 		// If any dependent then it's not async. Since dependent is not set to defer the final strategy will be blocking.
 		wp_enqueue_script( 'main-script-a3', '/main-script-a3.js', array(), null, array( 'strategy' => 'async' ) );
 		wp_enqueue_script( 'dependent-script-a3', '/dependent-script-a3.js', array( 'main-script-a3' ), null );
 		$output       = get_echo( 'wp_print_scripts' );
-		$not_expected = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js' async></script>";
 		$expected     = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js'></script>";
-		$this->assertStringNotContainsString( $not_expected, $output );
 		$this->assertStringContainsString( $expected, $output );
+	}
 
-		/**
-		 * Defer strategy testing.
-		 */
-		// Valid Defer cases.
+	/**
+	 * Test valid defer loading strategy cases.
+	 *
+	 * @ticket 12009
+	 */
+	public function test_loading_strategy_with_valid_defer_registration() {
 		// No dependents, No dependencies and defer strategy.
 		wp_enqueue_script( 'main-script-d1', '/main-script-d1.js', array(), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
@@ -125,24 +126,30 @@ public function test_loading_strategy() {
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='/main-script-d3.js' id='main-script-d3-js' defer></script>\n";
 		$this->assertStringContainsString( $expected, $output );
+	}
 
-		// Invalid defer.
+	/**
+	 * Test invalid defer loading strategy case.
+	 *
+	 * @ticket 12009
+	 */
+	public function test_loading_strategy_with_invalid_defer_registration() {
 		// Main script is defer and all dependent are not defer. Then main script will have blocking(or no) strategy.
 		wp_enqueue_script( 'main-script-d4', '/main-script-d4.js', array(), null, array( 'strategy' => 'defer' ) );
 		wp_enqueue_script( 'dependent-script-d4-1', '/dependent-script-d4-1.js', array( 'main-script-d4' ), null, array( 'strategy' => 'defer' ) );
 		wp_enqueue_script( 'dependent-script-d4-2', '/dependent-script-d4-2.js', array( 'dependent-script-d4-1' ), null, array( 'strategy' => 'blocking' ) );
 		wp_enqueue_script( 'dependent-script-d4-3', '/dependent-script-d4-3.js', array( 'dependent-script-d4-2' ), null, array( 'strategy' => 'defer' ) );
 		$output       = get_echo( 'wp_print_scripts' );
-		$not_expected = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js' defer></script>\n";
 		$expected     = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js'></script>\n";
-		$this->assertStringNotContainsString( $not_expected, $output );
 		$this->assertStringContainsString( $expected, $output );
+	}
 
-		/**
-		 * Blocking(or no) strategy testing.
-		 */
-		// Valid Defer cases.
-		// args set as blocking.
+	/**
+	 * Test valid blocking loading strategy cases.
+	 *
+	 * @ticket 12009
+	 */
+	public function test_loading_strategy_with_valid_blocking_registration() {
 		wp_enqueue_script( 'main-script-b1', '/main-script-b1.js', array(), null, array( 'strategy' => 'blocking' ) );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='/main-script-b1.js' id='main-script-b1-js'></script>\n";

From 0f80794456215b3a3559d42989e331dca659fddc Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 15:24:32 +0000
Subject: [PATCH 40/43] breaking test to dataprovider

---
 tests/phpunit/tests/dependencies/scripts.php | 57 +++++++++++---------
 1 file changed, 33 insertions(+), 24 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index dd9bd4aff8a83..49104d6b68eba 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -85,47 +85,56 @@ public function test_loading_strategy_with_invalid_async_registration() {
 		// If any dependencies then it's not async. Since dependency is blocking(/defer) final strategy will be defer.
 		wp_enqueue_script( 'dependency-script-a2', '/dependency-script-a2.js', array(), null );
 		wp_enqueue_script( 'main-script-a2', '/main-script-a2.js', array( 'dependency-script-a2' ), null, array( 'strategy' => 'async' ) );
-		$output       = get_echo( 'wp_print_scripts' );
-		$expected     = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' defer></script>";
-		$this->assertStringContainsString( $expected, $output );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-a2.js' id='main-script-a2-js' defer></script>";
+		$this->assertStringContainsString( $expected, $output, 'Expected defer.' );
 
 		// If any dependent then it's not async. Since dependent is not set to defer the final strategy will be blocking.
 		wp_enqueue_script( 'main-script-a3', '/main-script-a3.js', array(), null, array( 'strategy' => 'async' ) );
 		wp_enqueue_script( 'dependent-script-a3', '/dependent-script-a3.js', array( 'main-script-a3' ), null );
-		$output       = get_echo( 'wp_print_scripts' );
-		$expected     = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js'></script>";
-		$this->assertStringContainsString( $expected, $output );
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-a3.js' id='main-script-a3-js'></script>";
+		$this->assertStringContainsString( $expected, $output, 'Expected blocking.' );
 	}
 
 	/**
 	 * Test valid defer loading strategy cases.
 	 *
 	 * @ticket 12009
+	 * @dataProvider data_loading_strategy_with_valid_defer_registration
 	 */
-	public function test_loading_strategy_with_valid_defer_registration() {
+	public function test_loading_strategy_with_valid_defer_registration( $expected, $output ) {
+		$this->assertStringContainsString( $expected, $output );
+	}
+
+	public function data_loading_strategy_with_valid_defer_registration() {
+		$data = array();
+
 		// No dependents, No dependencies and defer strategy.
-		wp_enqueue_script( 'main-script-d1', '/main-script-d1.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'main-script-d1', 'http://example.com/main-script-d1.js', array(), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
-		$expected = "<script type='text/javascript' src='/main-script-d1.js' id='main-script-d1-js' defer></script>\n";
-		$this->assertSame( $expected, $output );
+		$expected = "<script type='text/javascript' src='http://example.com/main-script-d1.js' id='main-script-d1-js' defer></script>\n";
+		array_push( $data, array( $expected, $output ) );
 
 		// Main script is defer and all dependencies are either defer/blocking.
-		wp_enqueue_script( 'dependency-script-d2-1', '/dependency-script-d2-1.js', array(), null, array( 'strategy' => 'defer' ) );
-		wp_enqueue_script( 'dependency-script-d2-2', '/dependency-script-d2-2.js', array(), null, array( 'strategy' => 'blocking' ) );
-		wp_enqueue_script( 'dependency-script-d2-3', '/dependency-script-d2-3.js', array( 'dependency-script-d2-2' ), null, array( 'strategy' => 'defer' ) );
-		wp_enqueue_script( 'main-script-d2', '/main-script-d2.js', array( 'dependency-script-d2-1', 'dependency-script-d2-3' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependency-script-d2-1', 'http://example.com/dependency-script-d2-1.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependency-script-d2-2', 'http://example.com/dependency-script-d2-2.js', array(), null, array( 'strategy' => 'blocking' ) );
+		wp_enqueue_script( 'dependency-script-d2-3', 'http://example.com/dependency-script-d2-3.js', array( 'dependency-script-d2-2' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'main-script-d2', 'http://example.com/main-script-d2.js', array( 'dependency-script-d2-1', 'dependency-script-d2-3' ), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
-		$expected = "<script type='text/javascript' src='/main-script-d2.js' id='main-script-d2-js' defer></script>\n";
-		$this->assertStringContainsString( $expected, $output );
+		$expected = "<script type='text/javascript' src='http://example.com/main-script-d2.js' id='main-script-d2-js' defer></script>\n";
+		array_push( $data, array( $expected, $output ) );
 
 		// Main script is defer and all dependent are defer.
-		wp_enqueue_script( 'main-script-d3', '/main-script-d3.js', array(), null, array( 'strategy' => 'defer' ) );
-		wp_enqueue_script( 'dependent-script-d3-1', '/dependent-script-d3-1.js', array( 'main-script-d3' ), null, array( 'strategy' => 'defer' ) );
-		wp_enqueue_script( 'dependent-script-d3-2', '/dependent-script-d3-2.js', array( 'dependent-script-d3-1' ), null, array( 'strategy' => 'defer' ) );
-		wp_enqueue_script( 'dependent-script-d3-3', '/dependent-script-d3-3.js', array( 'dependent-script-d3-2' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'main-script-d3', 'http://example.com/main-script-d3.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-1', 'http://example.com/dependent-script-d3-1.js', array( 'main-script-d3' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-2', 'http://example.com/dependent-script-d3-2.js', array( 'dependent-script-d3-1' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d3-3', 'http://example.com/dependent-script-d3-3.js', array( 'dependent-script-d3-2' ), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
-		$expected = "<script type='text/javascript' src='/main-script-d3.js' id='main-script-d3-js' defer></script>\n";
-		$this->assertStringContainsString( $expected, $output );
+		$expected = "<script type='text/javascript' src='http://example.com/main-script-d3.js' id='main-script-d3-js' defer></script>\n";
+		array_push( $data, array( $expected, $output ) );
+
+		return $data;
 	}
 
 	/**
@@ -139,8 +148,8 @@ public function test_loading_strategy_with_invalid_defer_registration() {
 		wp_enqueue_script( 'dependent-script-d4-1', '/dependent-script-d4-1.js', array( 'main-script-d4' ), null, array( 'strategy' => 'defer' ) );
 		wp_enqueue_script( 'dependent-script-d4-2', '/dependent-script-d4-2.js', array( 'dependent-script-d4-1' ), null, array( 'strategy' => 'blocking' ) );
 		wp_enqueue_script( 'dependent-script-d4-3', '/dependent-script-d4-3.js', array( 'dependent-script-d4-2' ), null, array( 'strategy' => 'defer' ) );
-		$output       = get_echo( 'wp_print_scripts' );
-		$expected     = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js'></script>\n";
+		$output   = get_echo( 'wp_print_scripts' );
+		$expected = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js'></script>\n";
 		$this->assertStringContainsString( $expected, $output );
 	}
 

From f20cfeae472f53d69c30090a488fc925bc8ce3df Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 15:36:24 +0000
Subject: [PATCH 41/43] add async and defer check in dependent check

---
 src/wp-includes/class-wp-scripts.php | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-scripts.php b/src/wp-includes/class-wp-scripts.php
index 8ca9498494538..ffd4c426a504e 100644
--- a/src/wp-includes/class-wp-scripts.php
+++ b/src/wp-includes/class-wp-scripts.php
@@ -808,8 +808,8 @@ private function all_dependents_are_deferrable( $handle, $checked = array() ) {
 
 		// Consider each dependent and check if it is deferrable.
 		foreach ( $dependents as $dependent ) {
-			// If the dependent script is not using the defer strategy, no script in the chain is deferrable.
-			if ( 'defer' !== $this->get_intended_strategy( $dependent ) ) {
+			// If the dependent script is not using the defer or async strategy, no script in the chain is deferrable.
+			if ( ! in_array( $this->get_intended_strategy( $dependent ), array( 'defer', 'async' ), true ) ) {
 				return false;
 			}
 
@@ -828,16 +828,18 @@ private function all_dependents_are_deferrable( $handle, $checked = array() ) {
 	 * @return string $strategy return the final strategy.
 	 */
 	private function get_eligible_loading_strategy( $handle = '' ) {
+		if ( ! isset( $this->registered[ $handle ] ) ) {
+			return '';
+		}
 
 		$intended_strategy = $this->get_intended_strategy( $handle );
 		/*
 		 * Handle known blocking strategy scenarios.
 		 *
-		 * blocking if not a registered handle.
-		 * blocking if explicitly set.
 		 * blocking if script args not set.
+		 * blocking if explicitly set.
 		 */
-		if ( ! isset( $this->registered[ $handle ] ) || 'blocking' === $intended_strategy || ! $intended_strategy ) {
+		if ( ! $intended_strategy || 'blocking' === $intended_strategy ) {
 			return '';
 		}
 
@@ -846,7 +848,7 @@ private function get_eligible_loading_strategy( $handle = '' ) {
 			return 'async';
 		}
 
-		// Handling defer strategy scenarios. Dependency will never be set async. So only checking dependent.
+		// Handling defer strategy scenarios.
 		if ( $this->all_dependents_are_deferrable( $handle ) ) {
 			return 'defer';
 		}

From b961108c3561ef3d28f79971c6dbd32c2f12ac13 Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 15:58:28 +0000
Subject: [PATCH 42/43] defer with async dependent

---
 tests/phpunit/tests/dependencies/scripts.php | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 49104d6b68eba..0ba0b31fcac58 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -137,6 +137,26 @@ public function data_loading_strategy_with_valid_defer_registration() {
 		return $data;
 	}
 
+	/**
+	 * Test valid defer loading with async dependent.
+	 *
+	 * @ticket 12009
+	 */
+	public function test_defer_with_async_dependent() {
+		// case with one async dependent.
+		wp_enqueue_script( 'main-script-d4', '/main-script-d4.js', array(), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d4-1', '/dependent-script-d4-1.js', array( 'main-script-d4' ), null, array( 'strategy' => 'defer' ) );
+		wp_enqueue_script( 'dependent-script-d4-2', '/dependent-script-d4-2.js', array( 'dependent-script-d4-1' ), null, array( 'strategy' => 'async' ) );
+		wp_enqueue_script( 'dependent-script-d4-3', '/dependent-script-d4-3.js', array( 'dependent-script-d4-2' ), null, array( 'strategy' => 'defer' ) );
+		$output = get_echo( 'wp_print_scripts' );
+		$expected  = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js' defer></script>\n";
+		$expected .= "<script type='text/javascript' src='/dependent-script-d4-1.js' id='dependent-script-d4-1-js' defer></script>\n";
+		$expected .= "<script type='text/javascript' src='/dependent-script-d4-2.js' id='dependent-script-d4-2-js' defer></script>\n";
+		$expected .= "<script type='text/javascript' src='/dependent-script-d4-3.js' id='dependent-script-d4-3-js' defer></script>\n";
+
+		$this->assertSame( $expected, $output );
+	}
+
 	/**
 	 * Test invalid defer loading strategy case.
 	 *

From 70fb6c6e5ad81f2f1db661c6fbbfad3a86ad633f Mon Sep 17 00:00:00 2001
From: Karthik Thayyil <karthik.thayyil@get10up.com>
Date: Tue, 28 Feb 2023 18:39:37 +0000
Subject: [PATCH 43/43] Add failure messages

---
 tests/phpunit/tests/dependencies/scripts.php | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 0ba0b31fcac58..cd1582cc97c39 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -103,8 +103,8 @@ public function test_loading_strategy_with_invalid_async_registration() {
 	 * @ticket 12009
 	 * @dataProvider data_loading_strategy_with_valid_defer_registration
 	 */
-	public function test_loading_strategy_with_valid_defer_registration( $expected, $output ) {
-		$this->assertStringContainsString( $expected, $output );
+	public function test_loading_strategy_with_valid_defer_registration( $expected, $output, $message ) {
+		$this->assertStringContainsString( $expected, $output, $message );
 	}
 
 	public function data_loading_strategy_with_valid_defer_registration() {
@@ -114,7 +114,7 @@ public function data_loading_strategy_with_valid_defer_registration() {
 		wp_enqueue_script( 'main-script-d1', 'http://example.com/main-script-d1.js', array(), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='http://example.com/main-script-d1.js' id='main-script-d1-js' defer></script>\n";
-		array_push( $data, array( $expected, $output ) );
+		array_push( $data, array( $expected, $output, 'Expected defer, as there is no dependent or dependency' ) );
 
 		// Main script is defer and all dependencies are either defer/blocking.
 		wp_enqueue_script( 'dependency-script-d2-1', 'http://example.com/dependency-script-d2-1.js', array(), null, array( 'strategy' => 'defer' ) );
@@ -123,7 +123,7 @@ public function data_loading_strategy_with_valid_defer_registration() {
 		wp_enqueue_script( 'main-script-d2', 'http://example.com/main-script-d2.js', array( 'dependency-script-d2-1', 'dependency-script-d2-3' ), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='http://example.com/main-script-d2.js' id='main-script-d2-js' defer></script>\n";
-		array_push( $data, array( $expected, $output ) );
+		array_push( $data, array( $expected, $output, 'Expected defer, as all dependencies are either deferred or blocking' ) );
 
 		// Main script is defer and all dependent are defer.
 		wp_enqueue_script( 'main-script-d3', 'http://example.com/main-script-d3.js', array(), null, array( 'strategy' => 'defer' ) );
@@ -132,7 +132,7 @@ public function data_loading_strategy_with_valid_defer_registration() {
 		wp_enqueue_script( 'dependent-script-d3-3', 'http://example.com/dependent-script-d3-3.js', array( 'dependent-script-d3-2' ), null, array( 'strategy' => 'defer' ) );
 		$output   = get_echo( 'wp_print_scripts' );
 		$expected = "<script type='text/javascript' src='http://example.com/main-script-d3.js' id='main-script-d3-js' defer></script>\n";
-		array_push( $data, array( $expected, $output ) );
+		array_push( $data, array( $expected, $output, 'Expected defer, as all dependents have defer loading strategy' ) );
 
 		return $data;
 	}
@@ -148,7 +148,7 @@ public function test_defer_with_async_dependent() {
 		wp_enqueue_script( 'dependent-script-d4-1', '/dependent-script-d4-1.js', array( 'main-script-d4' ), null, array( 'strategy' => 'defer' ) );
 		wp_enqueue_script( 'dependent-script-d4-2', '/dependent-script-d4-2.js', array( 'dependent-script-d4-1' ), null, array( 'strategy' => 'async' ) );
 		wp_enqueue_script( 'dependent-script-d4-3', '/dependent-script-d4-3.js', array( 'dependent-script-d4-2' ), null, array( 'strategy' => 'defer' ) );
-		$output = get_echo( 'wp_print_scripts' );
+		$output    = get_echo( 'wp_print_scripts' );
 		$expected  = "<script type='text/javascript' src='/main-script-d4.js' id='main-script-d4-js' defer></script>\n";
 		$expected .= "<script type='text/javascript' src='/dependent-script-d4-1.js' id='dependent-script-d4-1-js' defer></script>\n";
 		$expected .= "<script type='text/javascript' src='/dependent-script-d4-2.js' id='dependent-script-d4-2-js' defer></script>\n";