Assumption safety checks for queried object

includes/classes/Feature/Facets/Types/Taxonomy/Renderer.php

@@ -72,10 +72,9 @@ public function render( $args, $instance ) {
 		$this->display_count = $instance['displayCount'];
 
 		if ( ! is_search() ) {
+			$post_type = Utils\get_post_types_for_tax_query();
 
-			if ( is_tax() ) {
-				$post_type = get_taxonomy( get_queried_object()->taxonomy )->object_type;
-			} else {
+			if ( empty( $post_type ) ) {
 				$post_type = $wp_query->get( 'post_type' ) ? $wp_query->get( 'post_type' ) : 'post';
 			}
 

includes/classes/Indexable/Post/QueryIntegration.php

@@ -243,11 +243,13 @@ public function get_es_posts( $posts, $query ) {
 		}
 
 		/**
-		 * If not search and not set default to post. If not set and is search, use searchable post types
+		 * If not search and not set, default to post. If not set and is search, use searchable post types.
 		 */
 		if ( empty( $query_vars['post_type'] ) ) {
-			if ( $query->is_tax() && $query->get_queried_object() ) {
-				$query_vars['post_type'] = get_taxonomy( $query->get_queried_object()->taxonomy )->object_type;
+			$tax_post_type = Utils\get_post_types_for_tax_query( $query );
+
+			if ( ! empty( $tax_post_type ) ) {
+				$query_vars['post_type'] = $tax_post_type;
 			} elseif ( empty( $query_vars['s'] ) ) {
 				$query_vars['post_type'] = 'post';
 			} else {

includes/utils.php

@@ -930,3 +930,40 @@ function is_top_level_admin_context() {
 	$is_network = defined( 'EP_IS_NETWORK' ) && EP_IS_NETWORK;
 	return $is_network ? is_network_admin() : is_admin();
 }
+
+/**
+ * Safely resolve the post type(s) for a taxonomy query.
+ *
+ * Guards against null queried objects, missing taxonomy properties,
+ * deregistered taxonomies, and non-post-type object types that would
+ * otherwise cause unexpected behavior when chaining
+ * get_queried_object()->taxonomy through get_taxonomy().
+ *
+ * @since 5.3.3
+ *
+ * @param \WP_Query|null $query Optional. WP_Query instance. Defaults to the global query.
+ * @return array Registered post type names on success, empty array otherwise.
+ */
+function get_post_types_for_tax_query( ?\WP_Query $query = null ): array {
+	global $wp_query;
+
+	if ( null === $query ) {
+		$query = $wp_query;
+	}
+
+	if ( ! $query instanceof \WP_Query || ! $query->is_tax() ) {
+		return [];
+	}
+
+	$queried_object = $query->get_queried_object();
+	if ( ! $queried_object || ! isset( $queried_object->taxonomy ) ) {
+		return [];
+	}
+
+	$taxonomy_object = get_taxonomy( $queried_object->taxonomy );
+	if ( ! $taxonomy_object || ! is_array( $taxonomy_object->object_type ) ) {
+		return [];
+	}
+
+	return array_values( array_filter( $taxonomy_object->object_type, 'post_type_exists' ) );
+}

tests/php/TestUtils.php

@@ -623,4 +623,19 @@ public function test_is_top_level_admin_context() {
 			$this->assertTrue( Utils\is_top_level_admin_context() );
 		}
 	}
+
+	/**
+	 * Test get_post_types_for_tax_query does not error when is_tax is true
+	 * but the queried object is invalid.
+	 *
+	 * @since 5.3.3
+	 * @group utils
+	 */
+	public function test_get_post_types_for_tax_query_invalid_queried_object() {
+		$query                 = new \WP_Query();
+		$query->is_tax         = true;
+		$query->queried_object = new \stdClass();
+
+		$this->assertSame( [], Utils\get_post_types_for_tax_query( $query ) );
+	}
 }