Shortcodes: Add shortcode_unautop to widget_block_content filter

src/wp-includes/default-filters.php

@@ -246,6 +246,7 @@
 add_filter( 'widget_text_content', 'wp_filter_content_tags', 12 ); // Runs after do_shortcode().
 
 add_filter( 'widget_block_content', 'do_blocks', 9 );
+add_filter( 'widget_block_content', 'shortcode_unautop' );
 add_filter( 'widget_block_content', 'do_shortcode', 11 );
 add_filter( 'widget_block_content', 'wp_filter_content_tags', 12 ); // Runs after do_shortcode().
 

tests/phpunit/tests/widgets/wpWidgetBlock.php

@@ -0,0 +1,94 @@
+<?php
+/**
+ * Unit tests covering WP_Widget_Block functionality.
+ *
+ * @package    WordPress
+ * @subpackage widgets
+ */
+
+/**
+ * Test wp-includes/widgets/class-wp-widget-block.php
+ *
+ * @group widgets
+ */
+class Tests_Widgets_wpWidgetBlock extends WP_UnitTestCase {
+
+	/**
+	 * Example shortcode content to test for wpautop corruption.
+	 *
+	 * @var string
+	 */
+	protected $example_shortcode_content = '<div class="shortcode-output">Example shortcode output.</div>';
+
+	/**
+	 * Number of times the shortcode was rendered.
+	 *
+	 * @var int
+	 */
+	protected $shortcode_render_count = 0;
+
+	/**
+	 * Sets up the test fixture.
+	 */
+	public function set_up() {
+		parent::set_up();
+		add_shortcode( 'example', array( $this, 'do_example_shortcode' ) );
+	}
+
+	/**
+	 * Tears down the test fixture.
+	 */
+	public function tear_down() {
+		remove_shortcode( 'example' );
+		parent::tear_down();
+	}
+
+	/**
+	 * Do example shortcode.
+	 *
+	 * @return string Shortcode content.
+	 */
+	public function do_example_shortcode() {
+		++$this->shortcode_render_count;
+		return $this->example_shortcode_content;
+	}
+
+	/**
+	 * Tests that the `<p>` wrapper added during server-side rendering of the shortcode
+	 * block is removed before do_shortcode() processes the shortcode.
+	 *
+	 * @ticket 62694
+	 *
+	 * @covers WP_Widget_Block::widget
+	 */
+	public function test_widget_shortcode_unautop() {
+		$args = array(
+			'before_title'  => '<h2>',
+			'after_title'   => "</h2>\n",
+			'before_widget' => '',
+			'after_widget'  => '',
+		);
+
+		$widget   = new WP_Widget_Block();
+		$instance = array(
+			'content' => "<!-- wp:shortcode -->\n[example]\n<!-- /wp:shortcode -->",
+		);
+
+		$this->shortcode_render_count = 0;
+		ob_start();
+		$widget->widget( $args, $instance );
+		$output = ob_get_clean();
+
+		$this->assertSame( 1, $this->shortcode_render_count, 'Shortcode was rendered once.' );
+		$this->assertStringContainsString(
+			$this->example_shortcode_content,
+			$output,
+			'Shortcode was applied without wpautop corrupting it.'
+		);
+		$this->assertStringNotContainsString(
+			'<p>' . $this->example_shortcode_content . '</p>',
+			$output,
+			'Expected shortcode_unautop() to have run.'
+		);
+	}
+}