bpo-44752: Make rlcompleter not call `@property` methods (GH-27401)

* rlcompleter was calling these methods to identify whether to add
  parenthesis to the completion, based on if the attribute is callable.
* for property objects, completion with parenthesis are never desirable.
* property methods with print statements behaved very strangely, which
  was especially unfriendly to language newcomers. <tab> could suddenly
  produce output unexpectedly.

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/rlcompleter.py b/Lib/rlcompleter.py
index c06388e..34b2599 100644
--- a/Lib/rlcompleter.py
+++ b/Lib/rlcompleter.py
@@ -176,6 +176,16 @@ class Completer:
                 if (word[:n] == attr and
                     not (noprefix and word[:n+1] == noprefix)):
                     match = "%s.%s" % (expr, word)
+                    if isinstance(getattr(type(thisobject), word, None),
+                                  property):
+                        # bpo-44752: thisobject.word is a method decorated by
+                        # `@property`. What follows applies a postfix if
+                        # thisobject.word is callable, but know we know that
+                        # this is not callable (because it is a property).
+                        # Also, getattr(thisobject, word) will evaluate the
+                        # property method, which is not desirable.
+                        matches.append(match)
+                        continue
                     try:
                         val = getattr(thisobject, word)
                     except Exception: