Bugfix in get_common_complete_suffix. Don't return any suffix when there are completions that change whatever is before the cursor.

2 files changed, 7 insertions, 3 deletions

diff --git a/prompt_toolkit/completion.py b/prompt_toolkit/completion.py
index ede5b969..056274a1 100644
--- a/prompt_toolkit/completion.py
+++ b/prompt_toolkit/completion.py
@@ -120,13 +120,18 @@ def get_common_complete_suffix(document, completions):
         end = completion.text[:-completion.start_position]
         return document.text_before_cursor.endswith(end)
 
-    completions = [c for c in completions if doesnt_change_before_cursor(c)]
+    completions2 = [c for c in completions if doesnt_change_before_cursor(c)]
+
+    # When there is at least one completion that changes the text before the
+    # cursor, don't return any common part.
+    if len(completions2) != len(completions):
+        return ''
 
     # Return the common prefix.
     def get_suffix(completion):
         return completion.text[-completion.start_position:]
 
-    return _commonprefix([get_suffix(c) for c in completions])
+    return _commonprefix([get_suffix(c) for c in completions2])
 
 
 def _commonprefix(strings):
diff --git a/prompt_toolkit/interface.py b/prompt_toolkit/interface.py
index a320e84e..f1e4e696 100644
--- a/prompt_toolkit/interface.py
+++ b/prompt_toolkit/interface.py
@@ -779,7 +779,6 @@ class CommandLineInterface(object):
                     complete_thread_running[0] = False
 
                     # When there is only one completion, which has nothing to add, ignore it.
-                    text_before_cursor = document.text_before_cursor
                     if (len(completions) == 1 and
                             completion_does_nothing(document, completions[0])):
                         del completions[:]