more robust logging setup

b2/_internal/console_tool.py

@@ -5380,7 +5380,7 @@ def _setup_logging(cls, args, argv):
         elif args.verbose or args.debug_logs:
             # set log level to DEBUG for ALL loggers (even those not belonging to B2), but without any handlers,
             # those will added as needed (file and/or stderr)
-            logging.basicConfig(level=logging.DEBUG, handlers=[])
+            logging.basicConfig(level=logging.DEBUG, handlers=[], errors='backslashreplace')
         else:
             logger.setLevel(logging.CRITICAL + 1)  # No logs!
         if args.verbose:
@@ -5395,7 +5395,7 @@ def _setup_logging(cls, args, argv):
                 '%(asctime)s\t%(process)d\t%(thread)d\t%(name)s\t%(levelname)s\t%(message)s'
             )
             formatter.converter = time.gmtime
-            handler = logging.FileHandler('b2_cli.log')
+            handler = logging.FileHandler('b2_cli.log', errors='backslashreplace')
             handler.setFormatter(formatter)
 
             # logs from ALL loggers sent to the log file should be formatted this way

changelog.d/+logging-encoding.fixed.md

@@ -0,0 +1 @@
+Escape invalid unicode characters in log messages.