Issue #25660: Fix TAB key behaviour in REPL.

Lib/rlcompleter.py

@@ -75,7 +75,9 @@ class Completer:
 
         if not text.strip():
             if state == 0:
-                return '\t'
+                readline.insert_text('\t')
+                readline.redisplay()
+                return ''
             else:
                 return None
 

Misc/NEWS

@@ -67,6 +67,9 @@ Core and Builtins
 - Issue #26171: Fix possible integer overflow and heap corruption in
   zipimporter.get_data().
 
+- Issue #25660: Fix TAB key behaviour in REPL with readline.
+
+
 Library
 -------