1 files changed, 5 insertions, 1 deletions
diff --git a/Lib/argparse.py b/Lib/argparse.py
index b69c5ad..1dacb7e 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -325,7 +325,11 @@ class HelpFormatter(object):
             if len(prefix) + len(usage) > text_width:
 
                 # break usage into wrappable parts
-                part_regexp = r'\(.*?\)+|\[.*?\]+|\S+'
+                part_regexp = (
+                    r'\(.*?\)+(?=\s|$)|'
+                    r'\[.*?\]+(?=\s|$)|'
+                    r'\S+'
+                )
                 opt_usage = format(optionals, groups)
                 pos_usage = format(positionals, groups)
                 opt_parts = _re.findall(part_regexp, opt_usage)