Don't replace user input when completion prefix is empty (Bug#18951)

* lisp/pcomplete.el (pcomplete-parse-arguments): Only replace user
input if we produced a non-empty common completion stub.

1 files changed, 1 insertions, 1 deletions

diff --git a/lisp/pcomplete.el b/lisp/pcomplete.el
index 745a813b758..2d2a8773bfe 100644
--- a/lisp/pcomplete.el
+++ b/lisp/pcomplete.el
@@ -772,7 +772,7 @@ this is `comint-dynamic-complete-functions'."
                 (setq c (cdr c)))
               (setq pcomplete-stub (substring common-stub 0 len)
                     pcomplete-autolist t)
-              (when (and begin (not pcomplete-show-list))
+              (when (and begin (> len 0) (not pcomplete-show-list))
                 (delete-region begin (point))
                 (pcomplete-insert-entry "" pcomplete-stub))
               (throw 'pcomplete-completions completions))