From cd5bdd4968bf8fe0236aad1750d852cf41882c85 2020-05-27 23:29:41
From: Matthias Bussonnier <bussonniermatthias@gmail.com>
Date: 2020-05-27 23:29:41
Subject: [PATCH] Backport PR #12305: Fix ipython#11508: check if line_buffer is None

---

diff --git a/IPython/core/completer.py b/IPython/core/completer.py
index 32144e1..bc114f0 100644
--- a/IPython/core/completer.py
+++ b/IPython/core/completer.py
@@ -1982,8 +1982,8 @@ class IPCompleter(Completer):
         # if text is either None or an empty string, rely on the line buffer
         if (not line_buffer) and full_text:
             line_buffer = full_text.split('\n')[cursor_line]
-        if not text:
-            text = self.splitter.split_line(line_buffer, cursor_pos)
+        if not text: # issue #11508: check line_buffer before calling split_line
+            text = self.splitter.split_line(line_buffer, cursor_pos)  if line_buffer else ''
 
         if self.backslash_combining_completions:
             # allow deactivation of these on windows.