Suppress PHPCS auto_detect_line_endings deprecation notice

includes/Checker/Checks/Abstract_PHP_CodeSniffer_Check.php

@@ -110,6 +110,8 @@ final public function run( Check_Result $result ) {
 		$_SERVER['argv'] = $this->parse_argv( $args, $defaults );
 
 		// Run PHPCS.
+		$this->register_php_codesniffer_error_handler();
+
 		try {
 			ob_start();
 			$runner = new Runner();
@@ -118,6 +120,8 @@ final public function run( Check_Result $result ) {
 		} catch ( Exception $e ) {
 			$_SERVER['argv'] = $orig_cmd_args;
 			throw $e;
+		} finally {
+			restore_error_handler();
 		}
 
 		// Reset installed_paths.
@@ -229,6 +233,35 @@ private function get_argv_defaults( Check_Result $result ): array {
 		return $defaults;
 	}
 
+	/**
+	 * Registers an error handler for known PHPCS notices.
+	 *
+	 * @since n.e.x.t
+	 */
+	private function register_php_codesniffer_error_handler() {
+		$previous_error_handler = null;
+
+		$previous_error_handler = set_error_handler(
+			static function ( $errno, $errstr, $errfile, $errline ) use ( &$previous_error_handler ) {
+				$normalized_file = wp_normalize_path( $errfile );
+
+				if (
+					E_DEPRECATED === $errno &&
+					false !== strpos( $errstr, 'auto_detect_line_endings is deprecated' ) &&
+					false !== strpos( $normalized_file, 'vendor/squizlabs/php_codesniffer/src/Runner.php' )
+				) {
+					return true;
+				}
+
+				if ( is_callable( $previous_error_handler ) ) {
+					return (bool) call_user_func( $previous_error_handler, $errno, $errstr, $errfile, $errline );
+				}
+
+				return false;
+			}
+		);
+	}
+
 	/**
 	 * Resets \PHP_CodeSniffer\Config::$overriddenDefaults to prevent
 	 * incorrect results when running multiple checks.

tests/phpunit/tests/Checker/Checks/Plugin_Review_PHPCS_Check_Tests.php

@@ -161,4 +161,29 @@ public function test_run_without_errors() {
 		$this->assertEquals( 0, $check_result->get_error_count() );
 		$this->assertEquals( 0, $check_result->get_warning_count() );
 	}
+
+	public function test_run_suppresses_phpcs_auto_detect_line_endings_deprecation() {
+		$plugin_review_phpcs_check = new Plugin_Review_PHPCS_Check();
+		$check_context             = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-review-phpcs-without-errors/load.php' );
+		$check_result              = new Check_Result( $check_context );
+
+		set_error_handler(
+			static function ( $errno, $errstr, $errfile, $errline ) {
+				if ( E_DEPRECATED === $errno && false !== strpos( $errstr, 'auto_detect_line_endings is deprecated' ) ) {
+					throw new ErrorException( $errstr, 0, $errno, $errfile, $errline );
+				}
+
+				return false;
+			}
+		);
+
+		try {
+			$plugin_review_phpcs_check->run( $check_result );
+		} finally {
+			restore_error_handler();
+		}
+
+		$this->assertEquals( 0, $check_result->get_error_count() );
+		$this->assertEquals( 0, $check_result->get_warning_count() );
+	}
 }