From 3499aad9cc29095550d4bf40523c71271a669e98 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Wed, 21 Oct 2020 13:47:42 +0200
Subject: [PATCH 01/14] Substitute the global by an internal static property

---
 src/wp-includes/class-wp-block-supports.php | 45 +++++++++++++++++----
 src/wp-includes/default-filters.php         |  1 +
 2 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 7bec60b85ddc9..13da79a66f27d 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -30,6 +30,13 @@ class WP_Block_Supports {
 	 */
 	private static $instance = null;
 
+	/**
+	 * Tracks the current block to be rendered.
+	 *
+	 * @var array
+	 */
+	private static $block_to_render = null;
+
 	/**
 	 * Utility method to retrieve the main instance of the class.
 	 *
@@ -57,6 +64,32 @@ public static function init() {
 		$instance->register_attributes();
 	}
 
+	/**
+	 * Callback hooked to the register_block_type_args filter.
+	 *
+	 * @since 5.6.0
+	 *
+	 * This hooks into block registration to wrap the render_callback
+	 * of dynamic blocks with a closure that keeps track of the
+	 * current block to be rendered.
+	 *
+	 * @param array $args Block attributes.
+	 * @return array Block attributes.
+	 */
+	public static function track_block_to_render( $args ) {
+		if ( null !== $args['render_callback'] ) {
+			$block_render_callback   = $args['render_callback'];
+			$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
+				$parent_block          = self::$block_to_render;
+				self::$block_to_render = $block->parsed_block;
+				$result                = $block_render_callback( $attributes, $content, $block );
+				self::$block_to_render = $parent_block;
+				return $result;
+			};
+		}
+		return $args;
+	}
+
 	/**
 	 * Registers a block support.
 	 *
@@ -79,13 +112,12 @@ public function register( $block_support_name, $block_support_config ) {
 	 *
 	 * @since 5.6.0
 	 *
-	 * @param  array $parsed_block Block as parsed from content.
 	 * @return array               Array of HTML attributes.
 	 */
-	public function apply_block_supports( $parsed_block ) {
-		$block_attributes = $parsed_block['attrs'];
+	public function apply_block_supports() {
+		$block_attributes = self::$block_to_render['attrs'];
 		$block_type       = WP_Block_Type_Registry::get_instance()->get_registered(
-			$parsed_block['blockName']
+			self::$block_to_render['blockName']
 		);
 
 		// If no render_callback, assume styles have been previously handled.
@@ -155,15 +187,12 @@ private function register_attributes() {
  *
  * @since 5.6.0
  *
- * @global array    $current_parsed_block Block currently being parsed.
- *
  * @param array $extra_attributes Optional. Extra attributes to render on the block wrapper.
  *
  * @return string String of HTML classes.
  */
 function get_block_wrapper_attributes( $extra_attributes = array() ) {
-	global $current_parsed_block;
-	$new_attributes = WP_Block_Supports::get_instance()->apply_block_supports( $current_parsed_block );
+	$new_attributes = WP_Block_Supports::get_instance()->apply_block_supports();
 
 	if ( empty( $new_attributes ) && empty( $extra_attributes ) ) {
 		return '';
diff --git a/src/wp-includes/default-filters.php b/src/wp-includes/default-filters.php
index 96ef7d82eb0f0..d99b5ae642f75 100644
--- a/src/wp-includes/default-filters.php
+++ b/src/wp-includes/default-filters.php
@@ -306,6 +306,7 @@
 add_action( 'init', '_register_core_block_patterns_and_categories' );
 add_action( 'init', 'check_theme_switched', 99 );
 add_action( 'init', array( 'WP_Block_Supports', 'init' ), 22 );
+add_filter( 'register_block_type_args', array( 'WP_Block_Supports', 'track_block_to_render' ) );
 add_action( 'after_switch_theme', '_wp_menus_changed' );
 add_action( 'after_switch_theme', '_wp_sidebars_changed' );
 add_action( 'wp_print_styles', 'print_emoji_styles' );

From a68cd0af157f6dbed1df403f2188de437e91b26e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Wed, 21 Oct 2020 13:49:19 +0200
Subject: [PATCH 02/14] Remove use of current_parsed_block global

---
 src/wp-includes/blocks.php                      | 17 +----------------
 src/wp-includes/class-wp-block.php              | 13 ++++---------
 .../includes/testcase-block-supports.php        |  5 +----
 3 files changed, 6 insertions(+), 29 deletions(-)

diff --git a/src/wp-includes/blocks.php b/src/wp-includes/blocks.php
index 206e7d3991adc..a1bde9a802951 100644
--- a/src/wp-includes/blocks.php
+++ b/src/wp-includes/blocks.php
@@ -647,24 +647,11 @@ function _excerpt_render_inner_columns_blocks( $columns, $allowed_blocks ) {
 	return $output;
 }
 
-/**
- * Block currently being parsed.
- *
- * @type array
-*/
-global $current_parsed_block;
-
-$current_parsed_block = array(
-	'blockName'  => null,
-	'attributes' => null,
-);
-
 /**
  * Renders a single block into a HTML string.
  *
  * @since 5.0.0
  *
- * @global array    $current_parsed_block Block currently being parsed.
  * @global WP_Post  $post                 The post to edit.
  * @global WP_Query $wp_query             WordPress Query object.
  * @global WP_Query $wp_query             WordPress Query object.
@@ -673,7 +660,7 @@ function _excerpt_render_inner_columns_blocks( $columns, $allowed_blocks ) {
  * @return string String of rendered HTML.
  */
 function render_block( $parsed_block ) {
-	global $post, $wp_query, $current_parsed_block;
+	global $post, $wp_query;
 
 	/**
 	 * Allows render_block() to be short-circuited, by returning a non-null value.
@@ -688,8 +675,6 @@ function render_block( $parsed_block ) {
 		return $pre_render;
 	}
 
-	$current_parsed_block = $parsed_block;
-
 	$source_block = $parsed_block;
 
 	/**
diff --git a/src/wp-includes/class-wp-block.php b/src/wp-includes/class-wp-block.php
index 135bad0d3352e..325ca6e65c535 100644
--- a/src/wp-includes/class-wp-block.php
+++ b/src/wp-includes/class-wp-block.php
@@ -192,7 +192,7 @@ public function __get( $name ) {
 	 * @return string Rendered block output.
 	 */
 	public function render( $options = array() ) {
-		global $post, $current_parsed_block;
+		global $post;
 		$options = wp_parse_args(
 			$options,
 			array(
@@ -206,14 +206,9 @@ public function render( $options = array() ) {
 		if ( ! $options['dynamic'] || empty( $this->block_type->skip_inner_blocks ) ) {
 			$index = 0;
 			foreach ( $this->inner_content as $chunk ) {
-				if ( is_string( $chunk ) ) {
-					$block_content .= $chunk;
-				} else {
-					$parent_parsed_block  = $current_parsed_block;
-					$current_parsed_block = $this->inner_blocks[ $index ]->parsed_block;
-					$block_content       .= $this->inner_blocks[ $index++ ]->render();
-					$current_parsed_block = $parent_parsed_block;
-				}
+				$block_content .= is_string( $chunk ) ?
+					$chunk :
+					$this->inner_blocks[ $index++ ]->render();
 			}
 		}
 
diff --git a/tests/phpunit/includes/testcase-block-supports.php b/tests/phpunit/includes/testcase-block-supports.php
index b5ed1310bcd92..617a19a070f3c 100644
--- a/tests/phpunit/includes/testcase-block-supports.php
+++ b/tests/phpunit/includes/testcase-block-supports.php
@@ -95,11 +95,8 @@ private function get_content_from_block( $block ) {
 	/**
 	 * Returns the rendered output for the current block.
 	 *
-	 * @param array $block Block to render.
 	 */
-	private function render_example_block( $block ) {
-		global $current_parsed_block;
-		$current_parsed_block = $block;
+	private function render_example_block() {
 		$wrapper_attributes   = get_block_wrapper_attributes(
 			array(
 				'class' => 'foo-bar-class',

From 150563e8c0093312dc8d385ab772d424e8f5847d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Wed, 21 Oct 2020 13:52:06 +0200
Subject: [PATCH 03/14] Fix linting issues

---
 tests/phpunit/includes/testcase-block-supports.php | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tests/phpunit/includes/testcase-block-supports.php b/tests/phpunit/includes/testcase-block-supports.php
index 617a19a070f3c..4441ab0438578 100644
--- a/tests/phpunit/includes/testcase-block-supports.php
+++ b/tests/phpunit/includes/testcase-block-supports.php
@@ -94,10 +94,9 @@ private function get_content_from_block( $block ) {
 
 	/**
 	 * Returns the rendered output for the current block.
-	 *
 	 */
 	private function render_example_block() {
-		$wrapper_attributes   = get_block_wrapper_attributes(
+		$wrapper_attributes = get_block_wrapper_attributes(
 			array(
 				'class' => 'foo-bar-class',
 				'style' => 'test: style;',

From dcd7f5ade715061f6c0195ba1f3b80a12c1ee0b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Thu, 22 Oct 2020 12:44:15 +0200
Subject: [PATCH 04/14] Extract wp_block_supports_track_block_to_render method

---
 src/wp-includes/class-wp-block-supports.php   | 63 +++++++++----------
 src/wp-includes/default-filters.php           |  2 +-
 .../includes/testcase-block-supports.php      | 10 ++-
 3 files changed, 39 insertions(+), 36 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 13da79a66f27d..7d5e99b7eee1c 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -24,18 +24,18 @@ class WP_Block_Supports {
 	private $block_supports = array();
 
 	/**
-	 * Container for the main instance of the class.
+	 * Tracks the current block to be rendered.
 	 *
-	 * @var WP_Block_Supports|null
+	 * @var array
 	 */
-	private static $instance = null;
+	public static $block_to_render = null;
 
 	/**
-	 * Tracks the current block to be rendered.
+	 * Container for the main instance of the class.
 	 *
-	 * @var array
+	 * @var WP_Block_Supports|null
 	 */
-	private static $block_to_render = null;
+	private static $instance = null;
 
 	/**
 	 * Utility method to retrieve the main instance of the class.
@@ -64,32 +64,6 @@ public static function init() {
 		$instance->register_attributes();
 	}
 
-	/**
-	 * Callback hooked to the register_block_type_args filter.
-	 *
-	 * @since 5.6.0
-	 *
-	 * This hooks into block registration to wrap the render_callback
-	 * of dynamic blocks with a closure that keeps track of the
-	 * current block to be rendered.
-	 *
-	 * @param array $args Block attributes.
-	 * @return array Block attributes.
-	 */
-	public static function track_block_to_render( $args ) {
-		if ( null !== $args['render_callback'] ) {
-			$block_render_callback   = $args['render_callback'];
-			$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
-				$parent_block          = self::$block_to_render;
-				self::$block_to_render = $block->parsed_block;
-				$result                = $block_render_callback( $attributes, $content, $block );
-				self::$block_to_render = $parent_block;
-				return $result;
-			};
-		}
-		return $args;
-	}
-
 	/**
 	 * Registers a block support.
 	 *
@@ -105,7 +79,6 @@ public function register( $block_support_name, $block_support_config ) {
 		);
 	}
 
-
 	/**
 	 * Generates an array of HTML attributes, such as classes, by applying to
 	 * the given block all of the features that the block supports.
@@ -238,3 +211,27 @@ function get_block_wrapper_attributes( $extra_attributes = array() ) {
 	return implode( ' ', $normalized_attributes );
 }
 
+
+/**
+ * Callback hooked to the register_block_type_args filter.
+ *
+ * This hooks into block registration to wrap the render_callback
+ * of dynamic blocks with a closure that keeps track of the
+ * current block to be rendered.
+ *
+ * @param array $args Block attributes.
+ * @return array Block attributes.
+ */
+function wp_block_supports_track_block_to_render( $args ) {
+	if ( null !== $args['render_callback'] ) {
+		$block_render_callback   = $args['render_callback'];
+		$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
+			$parent_block                       = WP_Block_Supports::$block_to_render;
+			WP_Block_Supports::$block_to_render = $block->parsed_block;
+			$result                             = $block_render_callback( $attributes, $content, $block );
+			WP_Block_Supports::$block_to_render = $parent_block;
+			return $result;
+		};
+	}
+	return $args;
+}
diff --git a/src/wp-includes/default-filters.php b/src/wp-includes/default-filters.php
index d99b5ae642f75..457517c4b03cb 100644
--- a/src/wp-includes/default-filters.php
+++ b/src/wp-includes/default-filters.php
@@ -306,7 +306,7 @@
 add_action( 'init', '_register_core_block_patterns_and_categories' );
 add_action( 'init', 'check_theme_switched', 99 );
 add_action( 'init', array( 'WP_Block_Supports', 'init' ), 22 );
-add_filter( 'register_block_type_args', array( 'WP_Block_Supports', 'track_block_to_render' ) );
+add_filter( 'register_block_type_args', 'wp_block_supports_track_block_to_render' );
 add_action( 'after_switch_theme', '_wp_menus_changed' );
 add_action( 'after_switch_theme', '_wp_sidebars_changed' );
 add_action( 'wp_print_styles', 'print_emoji_styles' );
diff --git a/tests/phpunit/includes/testcase-block-supports.php b/tests/phpunit/includes/testcase-block-supports.php
index 4441ab0438578..9f379696e3514 100644
--- a/tests/phpunit/includes/testcase-block-supports.php
+++ b/tests/phpunit/includes/testcase-block-supports.php
@@ -94,9 +94,15 @@ private function get_content_from_block( $block ) {
 
 	/**
 	 * Returns the rendered output for the current block.
+	 *
+	 * @param array $block Block to render.
+	 *
+	 * @return string Rendered output for the current block.
 	 */
-	private function render_example_block() {
-		$wrapper_attributes = get_block_wrapper_attributes(
+	private function render_example_block( $block ) {
+		WP_Block_Supports::init();
+		WP_Block_Supports::$block_to_render = $block;
+		$wrapper_attributes                 = get_block_wrapper_attributes(
 			array(
 				'class' => 'foo-bar-class',
 				'style' => 'test: style;',

From c61fff865781191a4eee63493181e3e3f726c6f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 12:52:10 +0200
Subject: [PATCH 05/14] Deprecate and patch the WP_Block_Type->render so is
 compatible with current code

Since:

    https://core.trac.wordpress.org/ticket/49927
    Commit 910de8f6890c87f93359c6f2edc6c27b9a3f3292 at wordpress-develop

we no longer use the render method of WP_Block_Type,
but its equivalent at WP_Block.

There's still some tests that use that old path that were failing
because the render_callback was called with only 2 arguments
instead of the three that WP_Block uses.

This commit:

- Signals WP_Block_Type->render as deprecated.
- Patch it to pass a null value as the third argument
  (it represents an instance of WP_Block).
---
 src/wp-includes/class-wp-block-supports.php | 20 +++++++++++++++-----
 src/wp-includes/class-wp-block-type.php     |  4 +++-
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 7d5e99b7eee1c..474ff85663b18 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -226,11 +226,21 @@ function wp_block_supports_track_block_to_render( $args ) {
 	if ( null !== $args['render_callback'] ) {
 		$block_render_callback   = $args['render_callback'];
 		$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
-			$parent_block                       = WP_Block_Supports::$block_to_render;
-			WP_Block_Supports::$block_to_render = $block->parsed_block;
-			$result                             = $block_render_callback( $attributes, $content, $block );
-			WP_Block_Supports::$block_to_render = $parent_block;
-			return $result;
+			// Check for null for back compatibility with WP_Block_Type->render
+			// which is unused since the introduction of WP_Block class.
+			//
+			// See:
+			// - https://core.trac.wordpress.org/ticket/49927
+			// - commit 910de8f6890c87f93359c6f2edc6c27b9a3f3292 at wordpress-develop
+			if ( null !== $block ) {
+				$parent_block                       = WP_Block_Supports::$block_to_render;
+				WP_Block_Supports::$block_to_render = $block->parsed_block;
+				$result                             = $block_render_callback( $attributes, $content, $block );
+				WP_Block_Supports::$block_to_render = $parent_block;
+				return $result;
+			} else {
+				return $block_render_callback( $attributes, $content );
+			}
 		};
 	}
 	return $args;
diff --git a/src/wp-includes/class-wp-block-type.php b/src/wp-includes/class-wp-block-type.php
index 7687d2b9317d9..bf3fd89ae1f9d 100644
--- a/src/wp-includes/class-wp-block-type.php
+++ b/src/wp-includes/class-wp-block-type.php
@@ -180,6 +180,8 @@ public function __construct( $block_type, $args = array() ) {
 	 *
 	 * @since 5.0.0
 	 *
+	 * @deprecated 5.6 See WP_Block->render introduced in 5.5.
+	 *
 	 * @param array  $attributes Optional. Block attributes. Default empty array.
 	 * @param string $content    Optional. Block content. Default empty string.
 	 * @return string Rendered block type output.
@@ -191,7 +193,7 @@ public function render( $attributes = array(), $content = '' ) {
 
 		$attributes = $this->prepare_attributes_for_render( $attributes );
 
-		return (string) call_user_func( $this->render_callback, $attributes, $content );
+		return (string) call_user_func( $this->render_callback, $attributes, $content, null );
 	}
 
 	/**

From 121e2a55e01c1c465f9a52561fe6e93160a5c362 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 13:20:00 +0200
Subject: [PATCH 06/14] Fix WP_Test_Block_Type->test_set_props

---
 tests/phpunit/tests/blocks/block-type.php | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/blocks/block-type.php b/tests/phpunit/tests/blocks/block-type.php
index e93aed05a2410..db2e26d270f2f 100644
--- a/tests/phpunit/tests/blocks/block-type.php
+++ b/tests/phpunit/tests/blocks/block-type.php
@@ -69,18 +69,21 @@ public static function wpSetUpBeforeClass() {
 
 	/**
 	 * @ticket 45097
+	 * 
+	 * @since 5.6 Removed testing whether render_callback
+	 * is the same as the one passed because we wrap
+	 * it in wp_block_supports_track_block_to_render
+	 * so it's not equal.
 	 */
 	public function test_set_props() {
 		$name = 'core/fake';
 		$args = array(
-			'render_callback' => array( $this, 'render_fake_block' ),
 			'foo'             => 'bar',
 		);
 
 		$block_type = new WP_Block_Type( $name, $args );
 
 		$this->assertSame( $name, $block_type->name );
-		$this->assertSame( $args['render_callback'], $block_type->render_callback );
 		$this->assertSame( $args['foo'], $block_type->foo );
 	}
 

From d3d7b9e5139bac50b18580520c2fbea74dda3b5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 13:25:42 +0200
Subject: [PATCH 07/14] Make linter happy

---
 tests/phpunit/tests/blocks/block-type.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/blocks/block-type.php b/tests/phpunit/tests/blocks/block-type.php
index db2e26d270f2f..aaf8ca088c2e3 100644
--- a/tests/phpunit/tests/blocks/block-type.php
+++ b/tests/phpunit/tests/blocks/block-type.php
@@ -69,7 +69,7 @@ public static function wpSetUpBeforeClass() {
 
 	/**
 	 * @ticket 45097
-	 * 
+	 *
 	 * @since 5.6 Removed testing whether render_callback
 	 * is the same as the one passed because we wrap
 	 * it in wp_block_supports_track_block_to_render

From 9561a9a178acbe8243316e2ce0a752e5d42f917e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 13:28:58 +0200
Subject: [PATCH 08/14] Make linter happy

---
 tests/phpunit/tests/blocks/block-type.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/blocks/block-type.php b/tests/phpunit/tests/blocks/block-type.php
index aaf8ca088c2e3..a5bd46c22dd8d 100644
--- a/tests/phpunit/tests/blocks/block-type.php
+++ b/tests/phpunit/tests/blocks/block-type.php
@@ -78,7 +78,7 @@ public static function wpSetUpBeforeClass() {
 	public function test_set_props() {
 		$name = 'core/fake';
 		$args = array(
-			'foo'             => 'bar',
+			'foo' => 'bar',
 		);
 
 		$block_type = new WP_Block_Type( $name, $args );

From ace4d440f495b09f55bdd424a46c0078a45a5b5f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 13:46:35 +0200
Subject: [PATCH 09/14] Fix
 REST_Block_Type_Controller_Test->test_get_item_invalid

Because the render_callback is now wrapped by a function
at src/wp-includes/class-wp-block-supports.php it'll
be callable. So we pass null as the callback
and the wrapper won't be attached.
---
 tests/phpunit/tests/rest-api/rest-block-type-controller.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/rest-api/rest-block-type-controller.php b/tests/phpunit/tests/rest-api/rest-block-type-controller.php
index 06db6d96759c4..7daaf4b23105b 100644
--- a/tests/phpunit/tests/rest-api/rest-block-type-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-block-type-controller.php
@@ -222,7 +222,7 @@ public function test_get_item_invalid() {
 			'parent'           => 'invalid_parent',
 			'supports'         => 'invalid_supports',
 			'styles'           => 'invalid_styles',
-			'render_callback'  => 'invalid_callback',
+			'render_callback'  => null,
 			'textdomain'       => true,
 		);
 		register_block_type( $block_type, $settings );

From 6e51b2fabf84851a839a51e4ff015fb99939fb7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 14:04:44 +0200
Subject: [PATCH 10/14] Improve the check we use to decide whether to attach
 the wrapper

By using is_callable we make sure that we don't change any
callback behavior:

- if the original callback is callable => attach the wrapper
- if the original callback is not callable => no wrapper
---
 src/wp-includes/class-wp-block-supports.php                 | 2 +-
 tests/phpunit/tests/rest-api/rest-block-type-controller.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 474ff85663b18..1cf6c991ebbda 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -223,7 +223,7 @@ function get_block_wrapper_attributes( $extra_attributes = array() ) {
  * @return array Block attributes.
  */
 function wp_block_supports_track_block_to_render( $args ) {
-	if ( null !== $args['render_callback'] ) {
+	if ( is_callable( $args['render_callback'] ) ) {
 		$block_render_callback   = $args['render_callback'];
 		$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
 			// Check for null for back compatibility with WP_Block_Type->render
diff --git a/tests/phpunit/tests/rest-api/rest-block-type-controller.php b/tests/phpunit/tests/rest-api/rest-block-type-controller.php
index 7daaf4b23105b..06db6d96759c4 100644
--- a/tests/phpunit/tests/rest-api/rest-block-type-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-block-type-controller.php
@@ -222,7 +222,7 @@ public function test_get_item_invalid() {
 			'parent'           => 'invalid_parent',
 			'supports'         => 'invalid_supports',
 			'styles'           => 'invalid_styles',
-			'render_callback'  => null,
+			'render_callback'  => 'invalid_callback',
 			'textdomain'       => true,
 		);
 		register_block_type( $block_type, $settings );

From 8b5d3c6059a306aed4ecefda8032ae5d8e83432b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 16:55:11 +0200
Subject: [PATCH 11/14] Let callback receive 2 or 3 parameters

---
 src/wp-includes/class-wp-block-supports.php | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 1cf6c991ebbda..79302b5c9f950 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -225,22 +225,23 @@ function get_block_wrapper_attributes( $extra_attributes = array() ) {
 function wp_block_supports_track_block_to_render( $args ) {
 	if ( is_callable( $args['render_callback'] ) ) {
 		$block_render_callback   = $args['render_callback'];
-		$args['render_callback'] = function( $attributes, $content, $block ) use ( $block_render_callback ) {
+		$args['render_callback'] = function( $attributes, $content, $block = null ) use ( $block_render_callback ) {
 			// Check for null for back compatibility with WP_Block_Type->render
 			// which is unused since the introduction of WP_Block class.
 			//
 			// See:
 			// - https://core.trac.wordpress.org/ticket/49927
-			// - commit 910de8f6890c87f93359c6f2edc6c27b9a3f3292 at wordpress-develop
-			if ( null !== $block ) {
-				$parent_block                       = WP_Block_Supports::$block_to_render;
-				WP_Block_Supports::$block_to_render = $block->parsed_block;
-				$result                             = $block_render_callback( $attributes, $content, $block );
-				WP_Block_Supports::$block_to_render = $parent_block;
-				return $result;
-			} else {
+			// - commit 910de8f6890c87f93359c6f2edc6c27b9a3f3292 at wordpress-develop.
+
+			if ( null === $block ) {
 				return $block_render_callback( $attributes, $content );
 			}
+
+			$parent_block                       = WP_Block_Supports::$block_to_render;
+			WP_Block_Supports::$block_to_render = $block->parsed_block;
+			$result                             = $block_render_callback( $attributes, $content, $block );
+			WP_Block_Supports::$block_to_render = $parent_block;
+			return $result;
 		};
 	}
 	return $args;

From 31c1565552136300e18f968eb2120f5537c82084 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 17:18:36 +0200
Subject: [PATCH 12/14] Remove unnecessary parameter

---
 src/wp-includes/class-wp-block-type.php   | 4 +---
 tests/phpunit/tests/blocks/block-type.php | 5 ++---
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-block-type.php b/src/wp-includes/class-wp-block-type.php
index bf3fd89ae1f9d..7687d2b9317d9 100644
--- a/src/wp-includes/class-wp-block-type.php
+++ b/src/wp-includes/class-wp-block-type.php
@@ -180,8 +180,6 @@ public function __construct( $block_type, $args = array() ) {
 	 *
 	 * @since 5.0.0
 	 *
-	 * @deprecated 5.6 See WP_Block->render introduced in 5.5.
-	 *
 	 * @param array  $attributes Optional. Block attributes. Default empty array.
 	 * @param string $content    Optional. Block content. Default empty string.
 	 * @return string Rendered block type output.
@@ -193,7 +191,7 @@ public function render( $attributes = array(), $content = '' ) {
 
 		$attributes = $this->prepare_attributes_for_render( $attributes );
 
-		return (string) call_user_func( $this->render_callback, $attributes, $content, null );
+		return (string) call_user_func( $this->render_callback, $attributes, $content );
 	}
 
 	/**
diff --git a/tests/phpunit/tests/blocks/block-type.php b/tests/phpunit/tests/blocks/block-type.php
index a5bd46c22dd8d..c42d8b2844d85 100644
--- a/tests/phpunit/tests/blocks/block-type.php
+++ b/tests/phpunit/tests/blocks/block-type.php
@@ -70,9 +70,8 @@ public static function wpSetUpBeforeClass() {
 	/**
 	 * @ticket 45097
 	 *
-	 * @since 5.6 Removed testing whether render_callback
-	 * is the same as the one passed because we wrap
-	 * it in wp_block_supports_track_block_to_render
+	 * @since 5.6 Removed assertion for render_callback.
+	 * We wrap that function in wp_block_supports_track_block_to_render
 	 * so it's not equal.
 	 */
 	public function test_set_props() {

From 99fe74341099d7fca1ca730cb5ff80a105cfdaa4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 17:31:10 +0200
Subject: [PATCH 13/14] Update the block_to_render property in WP_Block->render

---
 src/wp-includes/class-wp-block-supports.php | 36 ---------------------
 src/wp-includes/class-wp-block.php          |  3 ++
 src/wp-includes/default-filters.php         |  1 -
 tests/phpunit/tests/blocks/block-type.php   |  8 ++---
 4 files changed, 6 insertions(+), 42 deletions(-)

diff --git a/src/wp-includes/class-wp-block-supports.php b/src/wp-includes/class-wp-block-supports.php
index 79302b5c9f950..27da185a20921 100644
--- a/src/wp-includes/class-wp-block-supports.php
+++ b/src/wp-includes/class-wp-block-supports.php
@@ -210,39 +210,3 @@ function get_block_wrapper_attributes( $extra_attributes = array() ) {
 
 	return implode( ' ', $normalized_attributes );
 }
-
-
-/**
- * Callback hooked to the register_block_type_args filter.
- *
- * This hooks into block registration to wrap the render_callback
- * of dynamic blocks with a closure that keeps track of the
- * current block to be rendered.
- *
- * @param array $args Block attributes.
- * @return array Block attributes.
- */
-function wp_block_supports_track_block_to_render( $args ) {
-	if ( is_callable( $args['render_callback'] ) ) {
-		$block_render_callback   = $args['render_callback'];
-		$args['render_callback'] = function( $attributes, $content, $block = null ) use ( $block_render_callback ) {
-			// Check for null for back compatibility with WP_Block_Type->render
-			// which is unused since the introduction of WP_Block class.
-			//
-			// See:
-			// - https://core.trac.wordpress.org/ticket/49927
-			// - commit 910de8f6890c87f93359c6f2edc6c27b9a3f3292 at wordpress-develop.
-
-			if ( null === $block ) {
-				return $block_render_callback( $attributes, $content );
-			}
-
-			$parent_block                       = WP_Block_Supports::$block_to_render;
-			WP_Block_Supports::$block_to_render = $block->parsed_block;
-			$result                             = $block_render_callback( $attributes, $content, $block );
-			WP_Block_Supports::$block_to_render = $parent_block;
-			return $result;
-		};
-	}
-	return $args;
-}
diff --git a/src/wp-includes/class-wp-block.php b/src/wp-includes/class-wp-block.php
index 325ca6e65c535..2142fbeeb5616 100644
--- a/src/wp-includes/class-wp-block.php
+++ b/src/wp-includes/class-wp-block.php
@@ -214,7 +214,10 @@ public function render( $options = array() ) {
 
 		if ( $is_dynamic ) {
 			$global_post   = $post;
+			$parent = WP_Block_Supports::$block_to_render;
+			WP_Block_Supports::$block_to_render = $this;
 			$block_content = (string) call_user_func( $this->block_type->render_callback, $this->attributes, $block_content, $this );
+			WP_Block_Supports::$block_to_render = $parent;
 			$post          = $global_post;
 		}
 
diff --git a/src/wp-includes/default-filters.php b/src/wp-includes/default-filters.php
index 457517c4b03cb..96ef7d82eb0f0 100644
--- a/src/wp-includes/default-filters.php
+++ b/src/wp-includes/default-filters.php
@@ -306,7 +306,6 @@
 add_action( 'init', '_register_core_block_patterns_and_categories' );
 add_action( 'init', 'check_theme_switched', 99 );
 add_action( 'init', array( 'WP_Block_Supports', 'init' ), 22 );
-add_filter( 'register_block_type_args', 'wp_block_supports_track_block_to_render' );
 add_action( 'after_switch_theme', '_wp_menus_changed' );
 add_action( 'after_switch_theme', '_wp_sidebars_changed' );
 add_action( 'wp_print_styles', 'print_emoji_styles' );
diff --git a/tests/phpunit/tests/blocks/block-type.php b/tests/phpunit/tests/blocks/block-type.php
index c42d8b2844d85..e93aed05a2410 100644
--- a/tests/phpunit/tests/blocks/block-type.php
+++ b/tests/phpunit/tests/blocks/block-type.php
@@ -69,20 +69,18 @@ public static function wpSetUpBeforeClass() {
 
 	/**
 	 * @ticket 45097
-	 *
-	 * @since 5.6 Removed assertion for render_callback.
-	 * We wrap that function in wp_block_supports_track_block_to_render
-	 * so it's not equal.
 	 */
 	public function test_set_props() {
 		$name = 'core/fake';
 		$args = array(
-			'foo' => 'bar',
+			'render_callback' => array( $this, 'render_fake_block' ),
+			'foo'             => 'bar',
 		);
 
 		$block_type = new WP_Block_Type( $name, $args );
 
 		$this->assertSame( $name, $block_type->name );
+		$this->assertSame( $args['render_callback'], $block_type->render_callback );
 		$this->assertSame( $args['foo'], $block_type->foo );
 	}
 

From 958efc8e6220b8b11dc4cac24fd102f7a2e95478 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s?= <andres.maneiro@automattic.com>
Date: Fri, 23 Oct 2020 17:44:29 +0200
Subject: [PATCH 14/14] Fix typo

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

diff --git a/src/wp-includes/class-wp-block.php b/src/wp-includes/class-wp-block.php
index 2142fbeeb5616..e2630a451a1c3 100644
--- a/src/wp-includes/class-wp-block.php
+++ b/src/wp-includes/class-wp-block.php
@@ -215,7 +215,7 @@ public function render( $options = array() ) {
 		if ( $is_dynamic ) {
 			$global_post   = $post;
 			$parent = WP_Block_Supports::$block_to_render;
-			WP_Block_Supports::$block_to_render = $this;
+			WP_Block_Supports::$block_to_render = $this->parsed_block;
 			$block_content = (string) call_user_func( $this->block_type->render_callback, $this->attributes, $block_content, $this );
 			WP_Block_Supports::$block_to_render = $parent;
 			$post          = $global_post;