Fix false "SITE IS DISCONNECTED" error on empty query results

classes/class-cli.php

@@ -223,14 +223,19 @@ private function csv_format( $records ) {
 	 * @return void
 	 */
 	private function connection() {
-		$query = wp_stream_get_instance()->db->query(
+		global $wpdb;
+
+		wp_stream_get_instance()->db->query(
 			array(
 				'records_per_page' => 1,
 				'fields'           => 'created',
 			)
 		);
 
-		if ( ! $query ) {
+		// An empty result set is valid (e.g. a fresh site with no logged
+		// activity yet); only a genuine database error means the site is
+		// disconnected.
+		if ( ! empty( $wpdb->last_error ) ) {
 			\WP_CLI::error( esc_html__( 'SITE IS DISCONNECTED', 'stream' ) );
 		}
 	}

tests/phpunit/test-class-cli.php

@@ -0,0 +1,74 @@
+<?php
+namespace WP_Stream;
+
+use ReflectionMethod;
+use ReflectionProperty;
+use WP_CLI;
+use WP_CLI\ExitException;
+
+class Test_CLI extends WP_StreamTestCase {
+	/**
+	 * Invokes the private CLI::connection() method, capturing any
+	 * WP_CLI::error() exit as an ExitException instead of terminating
+	 * the test process.
+	 *
+	 * @throws ExitException When the connection check fails.
+	 */
+	private function invoke_connection() {
+		$capture_exit = new ReflectionProperty( WP_CLI::class, 'capture_exit' );
+		$capture_exit->setAccessible( true );
+		$capture_exit->setValue( null, true );
+
+		$connection = new ReflectionMethod( CLI::class, 'connection' );
+		$connection->setAccessible( true );
+
+		try {
+			$connection->invoke( new CLI() );
+		} finally {
+			$capture_exit->setValue( null, false );
+		}
+	}
+
+	/**
+	 * A query that legitimately matches zero records is not a disconnection.
+	 */
+	public function test_connection_does_not_error_on_empty_result() {
+		global $wpdb;
+
+		// Force the connection check's query to match nothing, without
+		// touching any actual data other tests rely on.
+		$force_no_matches = function ( $where ) {
+			return $where . ' AND 1=0';
+		};
+		add_filter( 'wp_stream_db_query_where', $force_no_matches );
+
+		try {
+			$this->invoke_connection();
+		} finally {
+			remove_filter( 'wp_stream_db_query_where', $force_no_matches );
+		}
+
+		// Reaching this line means WP_CLI::error() was never triggered.
+		$this->assertEmpty( $wpdb->last_error );
+	}
+
+	/**
+	 * A genuine database error should still be reported as a disconnected site.
+	 */
+	public function test_connection_errors_on_database_failure() {
+		global $wpdb;
+
+		$original_table = $wpdb->stream;
+		$wpdb->stream   = $wpdb->prefix . 'stream_table_that_does_not_exist';
+		$wpdb->suppress_errors( true );
+
+		try {
+			$this->expectException( ExitException::class );
+			$this->invoke_connection();
+		} finally {
+			$wpdb->stream = $original_table;
+			$wpdb->suppress_errors( false );
+			$wpdb->last_error = '';
+		}
+	}
+}