Updated path completion for long path names to display the completed portion rather than the prefix. Will now elide for long file names as well as long object names.

Issue 11441

IPython/terminal/ptutils.py

@@ -24,7 +24,10 b' _completion_sentinel = object()'
 
 def _elide(string, *, min_elide=30):
     """
-    If a string is long enough, and has at least 2 dots,
+    If a string is long enough, and has at least 3 dots,
+    replace the middle part with ellipses.
+
+    If a string naming a file is long enough, and has at least 3 slashes,
     replace the middle part with ellipses.
 
     If three consecutive dots, or two consecutive dots are encountered these are
@@ -36,13 +39,17 b' def _elide(string, *, min_elide=30):'
     if len(string) < min_elide:
         return string
 
-    parts = string.split('.')
-
-    if len(parts) <= 3:
-        return string
+    object_parts = string.split('.')
+    file_parts = string.split('/')
 
+    if len(object_parts) > 3:
     return '{}.{}\N{HORIZONTAL ELLIPSIS}{}.{}'.format(parts[0], parts[1][0], parts[-2][-1], parts[-1])
 
+    elif len(file_parts) > 3:
+        return '{}/{}\N{HORIZONTAL ELLIPSIS}{}/{}'.format(parts[0], parts[1][0], parts[-2][-1], parts[-1])
+
+    return string
+
 
 def _adjust_completion_text_based_on_context(text, body, offset):
     if text.endswith('=') and len(body) > offset and body[offset] is '=':