Fix post editor layout when content block has no attributes.

src/wp-includes/block-editor.php

@@ -409,19 +409,20 @@ function wp_get_first_block( $blocks, $block_name ) {
  * Retrieves Post Content block attributes from the current post template.
  *
  * @since 6.3.0
+ * @since 6.4.0 Return null if there is no post content block.
  * @access private
  *
  * @global int $post_ID
  *
- * @return array Post Content block attributes or empty array if they don't exist.
+ * @return array|null Post Content block attributes array or null if Post Content block doesn't exist.
  */
 function wp_get_post_content_block_attributes() {
 	global $post_ID;
 
 	$is_block_theme = wp_is_block_theme();
 
 	if ( ! $is_block_theme || ! $post_ID ) {
-		return array();
+		return null;
 	}
 
 	$template_slug = get_page_template_slug( $post_ID );
@@ -457,12 +458,12 @@ function wp_get_post_content_block_attributes() {
 		$template_blocks    = parse_blocks( $current_template[0]->content );
 		$post_content_block = wp_get_first_block( $template_blocks, 'core/post-content' );
 
-		if ( ! empty( $post_content_block['attrs'] ) ) {
+		if ( isset( $post_content_block['attrs'] ) ) {
 			return $post_content_block['attrs'];
 		}
 	}
 
-	return array();
+	return null;
 }
 
 /**
@@ -635,7 +636,7 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 
 	$post_content_block_attributes = wp_get_post_content_block_attributes();
 
-	if ( ! empty( $post_content_block_attributes ) ) {
+	if ( isset( $post_content_block_attributes ) ) {
 		$editor_settings['postContentAttributes'] = $post_content_block_attributes;
 	}
 

tests/phpunit/data/themedir1/block-theme-post-content-default/style.css

@@ -0,0 +1,7 @@
+/*
+Theme Name: Block Theme Post Content Default
+Theme URI: https://wordpress.org/
+Description: For testing purposes only.
+Version: 1.0.0
+Text Domain: block-theme-post-content-default
+*/

tests/phpunit/data/themedir1/block-theme-post-content-default/templates/index.html

@@ -0,0 +1,3 @@
+<!-- wp:paragraph -->
+<p>Index Template</p>
+<!-- /wp:paragraph -->

tests/phpunit/data/themedir1/block-theme-post-content-default/templates/single.html

@@ -0,0 +1,2 @@
+<!-- wp:post-title {"level":1,"style":{"spacing":{"margin":{"bottom":"var:preset|spacing|40"}}}} /-->
+<!-- wp:post-content /-->

tests/phpunit/data/themedir1/block-theme-post-content-default/theme.json

@@ -0,0 +1,104 @@
+{
+	"version": 1,
+	"title": "Block theme",
+	"settings": {
+		"color": {
+			"palette": [
+				{
+					"slug": "light",
+					"name": "Light",
+					"color": "#f5f7f9"
+				},
+				{
+					"slug": "dark",
+					"name": "Dark",
+					"color": "#000"
+				}
+			],
+			"gradients": [
+				{
+					"name": "Custom gradient",
+					"gradient": "linear-gradient(135deg,rgba(0,0,0) 0%,rgb(0,0,0) 100%)",
+					"slug": "custom-gradient"
+				}
+			],
+			"duotone": [
+				{
+					"colors": [ "#333333", "#aaaaaa" ],
+					"slug": "custom-duotone",
+					"name": "Custom Duotone"
+				}
+			],
+			"custom": false,
+			"customGradient": false
+		},
+		"typography": {
+			"fontSizes": [
+				{
+					"name": "Custom",
+					"slug": "custom",
+					"size": "100px"
+				}
+			],
+			"customFontSize": false,
+			"customLineHeight": true
+		},
+		"spacing": {
+			"units": ["rem"],
+			"customPadding": true,
+			"blockGap": true
+		},
+		"blocks": {
+			"core/paragraph": {
+				"color": {
+					"palette": [
+						{
+							"slug": "light",
+							"name": "Light",
+							"color": "#f5f7f9"
+						}
+					]
+				}
+			}
+		}
+	},
+	"styles" : {
+		"blocks" :{
+			"core/post-featured-image": {
+				"shadow": "10px 10px 5px 0px rgba(0,0,0,0.66)",
+				"filter": {
+					"duotone": "var(--wp--preset--duotone--custom-duotone)"
+				}
+			}
+		},
+		"elements": {
+			"button": {
+				"shadow": "10px 10px 5px 0px rgba(0,0,0,0.66)"
+			},
+			"link": {
+				"typography": {
+					"textDecoration": "none"
+				},
+				"border": {
+					"bottom": {
+						"width": "2px",
+						"color": "currentColor",
+						"style": "solid"
+					}
+				},
+				":hover": {
+					"typography": {
+						"textDecoration": "none"
+					},
+					"border": {
+						"bottom": {
+							"width": "2px",
+							"color": "#000",
+							"style": "dotted"
+						}
+					}
+				}
+			}
+		}
+	}
+}

tests/phpunit/tests/blocks/editor.php

@@ -446,14 +446,20 @@ public function test_wp_get_post_content_block_attributes() {
 				'type' => 'constrained',
 			),
 		);
-		// With no block theme, expect an empty array.
-		$this->assertSame( array(), wp_get_post_content_block_attributes() );
+		// With no block theme, expect null.
+		$this->assertNull( wp_get_post_content_block_attributes() );
 
 		switch_theme( 'block-theme' );
 
 		$this->assertSame( $attributes_with_layout, wp_get_post_content_block_attributes() );
 	}
 
+	public function test_wp_get_post_content_block_attributes_no_layout() {
+		switch_theme( 'block-theme-post-content-default' );
+
+		$this->assertSame( array(), wp_get_post_content_block_attributes() );
+	}
+
 	/**
 	 * @ticket 53458
 	 */
@@ -527,6 +533,19 @@ public function test_get_block_editor_settings_theme_json_settings() {
 		switch_theme( WP_DEFAULT_THEME );
 	}
 
+	/**
+	 * @ticket 59358
+	 */
+	public function test_get_block_editor_settings_without_post_content_block() {
+
+		$post_editor_context = new WP_Block_Editor_Context( array( 'post' => get_post() ) );
+
+		$settings = get_block_editor_settings( array(), $post_editor_context );
+
+		$this->assertArrayNotHasKey( 'postContentAttributes', $settings );
+
+	}
+
 	/**
 	 * @ticket 52920
 	 * @expectedDeprecated block_editor_settings

tests/phpunit/tests/theme/themeDir.php

@@ -184,6 +184,7 @@ public function test_theme_list() {
 			'Block Theme [0.4.0]',
 			'Block Theme [1.0.0] in subdirectory',
 			'Block Theme Deprecated Path',
+			'Block Theme Post Content Default',
 			'Block Theme with defined Typography Fonts',
 			'Empty `fontFace` in theme.json - no webfonts defined',
 			'A theme with the Update URI header',