GH#1598: fix: preserve duplication table copy safety

inc/duplication/data.php

@@ -192,7 +192,7 @@ public static function should_copy_table($table, $table_base_name, $from_site_id
 			 * @param int    $from_site_id    Source site ID.
 			 * @param int    $to_site_id      Target site ID.
 			 */
-			return (bool) apply_filters('mucd_should_copy_table', $copy, $table, $table_base_name, $from_site_id, $to_site_id);
+			return (bool) apply_filters('wu_mucd_should_copy_table', $copy, $table, $table_base_name, $from_site_id, $to_site_id);
 		}
 
 		/**
@@ -248,7 +248,7 @@ public static function is_runtime_table($table_base_name) {
 			 *
 			 * @param array $runtime_tables Runtime-only table base names.
 			 */
-			$runtime_tables = (array) apply_filters('mucd_runtime_tables_to_ignore', $runtime_tables);
+			$runtime_tables = (array) apply_filters('wu_mucd_runtime_tables_to_ignore', $runtime_tables);
 
 			return in_array($table_base_name, $runtime_tables, true);
 		}
@@ -274,7 +274,7 @@ private static function should_skip_empty_table($table, $table_base_name, $from_
 				return false;
 			}
 
-			return 0 === self::get_table_row_count($table);
+			return ! self::table_has_rows($table);
 		}
 
 		/**
@@ -297,7 +297,7 @@ private static function skip_empty_tables($from_site_id, $to_site_id) {
 			 * @param int  $from_site_id      Source site ID.
 			 * @param int  $to_site_id        Target site ID.
 			 */
-			return (bool) apply_filters('mucd_skip_empty_tables', true, $from_site_id, $to_site_id);
+			return (bool) apply_filters('wu_mucd_skip_empty_tables', true, $from_site_id, $to_site_id);
 		}
 
 		/**
@@ -330,24 +330,30 @@ private static function is_required_table($table_base_name) {
 			 *
 			 * @param array $required_tables Required table base names.
 			 */
-			$required_tables = (array) apply_filters('mucd_required_tables_to_copy', $required_tables);
+			$required_tables = (array) apply_filters('wu_mucd_required_tables_to_copy', $required_tables);
 
 			return in_array($table_base_name, $required_tables, true);
 		}
 
 		/**
-		 * Count rows in a source table.
+		 * Check whether a source table has rows.
 		 *
 		 * @since 2.5.1
 		 *
 		 * @param string $table Full source table name.
-		 * @return int Source table row count.
+		 * @return bool Whether the source table has rows.
 		 */
-		private static function get_table_row_count($table) {
+		private static function table_has_rows($table) {
+			global $wpdb;
+
+			$wpdb->last_error = '';
+			$has_rows         = self::do_sql_query('SELECT 1 FROM `' . $table . '` LIMIT 1', 'var', false);
 
-			$count = self::do_sql_query('SELECT COUNT(*) FROM `' . $table . '`', 'var', false);
+			if ('' !== $wpdb->last_error) {
+				return true;
+			}
 
-			return (int) $count;
+			return null !== $has_rows;
 		}
 
 		/**

tests/WP_Ultimo/Duplication/MUCD_Data_Test.php

@@ -90,12 +90,12 @@
 	 * Test try_replace with serialized array data.
 	 */
 	public function test_try_replace_serialized_array() {
 		$data = serialize(['url' => 'https://example.com/old-site/page']);
 		$row  = ['meta_value' => $data];
 
 		$result = \MUCD_Data::try_replace($row, 'meta_value', 'example.com/old-site', 'example.com/new-site');
 
 		$unserialized = unserialize($result);
 		$this->assertEquals('https://example.com/new-site/page', $unserialized['url']);
 	}
 
@@ -103,17 +103,17 @@
 	 * Test try_replace with nested serialized data.
 	 */
 	public function test_try_replace_nested_serialized_array() {
 		$data = serialize([
 			'settings' => [
 				'link' => 'https://example.com/old-site/about',
 				'icon' => 'fa-home',
 			],
 			'content'  => 'Visit https://example.com/old-site for more',
 		]);
 		$row  = ['meta_value' => $data];
 
 		$result       = \MUCD_Data::try_replace($row, 'meta_value', 'example.com/old-site', 'example.com/new-site');
 		$unserialized = unserialize($result);
 
 		$this->assertEquals('https://example.com/new-site/about', $unserialized['settings']['link']);
 		$this->assertEquals('Visit https://example.com/new-site for more', $unserialized['content']);
@@ -135,12 +135,12 @@
 	 * Test try_replace with double-serialized data.
 	 */
 	public function test_try_replace_double_serialized() {
 		$data = serialize(serialize(['url' => 'https://example.com/old-site/page']));
 		$row  = ['meta_value' => $data];
 
 		$result = \MUCD_Data::try_replace($row, 'meta_value', 'example.com/old-site', 'example.com/new-site');
 
 		$unserialized = unserialize(unserialize($result));
 		$this->assertEquals('https://example.com/new-site/page', $unserialized['url']);
 	}
 
@@ -713,7 +713,7 @@
 		};
 
 		add_filter(
-			'mucd_should_copy_table',
+			'wu_mucd_should_copy_table',
 			$filter,
 			10,
 			3
@@ -724,10 +724,25 @@
 				\MUCD_Data::should_copy_table($table, 'actionscheduler_actions', get_current_blog_id(), 123)
 			);
 		} finally {
-			remove_filter('mucd_should_copy_table', $filter, 10);
+			remove_filter('wu_mucd_should_copy_table', $filter, 10);
 		}
 	}
 
+	/**
+	 * Test empty-table checks fail open when the row probe errors.
+	 */
+	public function test_should_copy_table_keeps_optional_table_when_row_probe_errors() {
+		global $wpdb;
+
+		$table = $wpdb->get_blog_prefix() . 'wu_missing_optional_fixture';
+
+		$this->drop_table_selection_fixture($table);
+
+		$this->assertTrue(
+			\MUCD_Data::should_copy_table($table, 'wu_missing_optional_fixture', get_current_blog_id(), 123)
+		);
+	}
+
 	/**
 	 * Create a temporary table used by table-selection tests.
 	 *