Convert HTML entities in titles before sending to Discourse

lib/discourse-publish.php

@@ -839,14 +839,14 @@ protected function get_excluded_tag_slugs() {
 	}
 
 	/**
-	 * Strip html tags from titles before passing them to Discourse.
+	 * Strip html tags and convert HTML entities before passing them to Discourse.
 	 *
 	 * @param string $title The title of the post.
 	 *
 	 * @return string
 	 */
 	protected function sanitize_title( $title ) {
-		return wp_strip_all_tags( $title );
+		return wp_specialchars_decode( wp_strip_all_tags( $title ) );
 	}
 
 	/**

tests/phpunit/test-discourse-publish.php

@@ -854,6 +854,46 @@ public function test_force_publish_max_age_prevents_older_posts_from_being_publi
 		wp_delete_post( $post_id );
 	}
 
+  /**
+   * Test that HTML entities are converted to their special characters.
+   */
+  public function test_conversion_of_html_entities_in_title() {
+		$title_with_entities = 'Title with &';
+		$title_with_decoded_entities = 'Title with &';
+		self::$post_atts['post_title'] = $title_with_entities;
+
+		$response         = $this->build_response( 'success' );
+		$response['body'] = $this->response_body_json( 'post_create' );
+
+		add_filter(
+			'pre_http_request',
+			function( $prempt, $args, $url ) use ( $response, $title_with_decoded_entities ) {
+				$body = json_decode( $args['body'] );
+
+				if ( $body->title !== $title_with_decoded_entities ) {
+						return new \WP_Error( 'http_request_failed', 'Failed to decode title' );
+				} else {
+					return $response;
+				}
+				},
+			10,
+			3
+		);
+
+		// Setup post.
+		$post_id = wp_insert_post( self::$post_atts, false, false );
+
+		// Run the publication.
+		$post = get_post( $post_id );
+		$this->publish->publish_post_after_save( $post_id, $post );
+
+		// Ensure publication occurs.
+		$this->assertEquals( get_post_meta( $post_id, 'wpdc_publishing_response', true ), 'success' );
+
+		// Cleanup.
+		wp_delete_post( $post_id );
+  }
+
 	/**
 	 * Posts can only be published via XMLRPC by hooking into the wp_discourse_before_xmlrpc_publish filter with a function
 	 * that returns `true`.