Merge pull request #10797 from Carreau/no-custom-completer-crash

Let keyboard interrupt stop custom dispatch of completer.

IPython/core/completer.py

@@ -1729,6 +1729,12 b' class IPCompleter(Completer):'
                     return [r for r in res if r.lower().startswith(text_low)]
             except TryNext:
                 pass
+            except KeyboardInterrupt:
+                """
+                If custom completer take too long,
+                let keyboard interrupt abort and return nothing.
+                """
+                break
 
         return None