Enhance widget visibility conditions to handle array content in Jetpack (#45080)

* Added logic to process $instance['content'] as an array, ensuring compatibility with nested structures and serialization of block arrays.
* Improved validation to return early if content is not a valid string after processing.

Author: LiamSarsfield

projects/plugins/jetpack/modules/widget-visibility/widget-conditions.php

@@ -827,7 +827,27 @@ public static function filter_widget( $instance ) {
 			}
 			return false;
 		} elseif ( ! empty( $instance['content'] ) && has_blocks( $instance['content'] ) ) {
-			$scanner = Block_Scanner::create( $instance['content'] );
+			$content = $instance['content'];
+			if ( is_array( $content ) ) {
+				// Handle case where $instance['content'] might be an array instead of string
+				if ( isset( $content['content'] ) && is_string( $content['content'] ) ) {
+					// Content is nested in array structure
+					$content = $content['content'];
+				} elseif ( ! empty( $content ) ) {
+					// Try to convert array of blocks back to string using serialize_blocks
+					$content = serialize_blocks( $content );
+				} else {
+					// Empty or invalid array, treat as no blocks
+					return $instance;
+				}
+			}
+
+			// Ensure content is still a string after processing
+			if ( ! is_string( $content ) || empty( $content ) ) {
+				return $instance;
+			}
+
+			$scanner = Block_Scanner::create( $content );
 			if ( ! $scanner ) {
 				// No Rules: Display widget.
 				return $instance;