tree b89794c46bd0b3992a3a5818c6a43c9f8bfeb84e
parent 2717a23b4e5c0fb73278fe9a53967834fc9ed269
author Jordan Rupprecht <rupprecht@google.com> 1617814520 -0700
committer Copybara-Service <copybara-worker@google.com> 1618252970 -0700

[lldb][Editline] Fix crash when navigating through empty command history.

An empty history entry can happen by entering the expression evaluator an immediately hitting enter:

```
$ lldb
(lldb) e
Enter expressions, then terminate with an empty line to evaluate:
  1:  <hit enter>
```

The next time the user enters the expression evaluator, if they hit the up arrow to load the previous expression, lldb crashes. This patch treats empty history sessions as a single expression of zero length, instead of an empty list of expressions.

Fixes http://llvm.org/PR49845.

Differential Revision: https://reviews.llvm.org/D100048

GitOrigin-RevId: f49a4440d38a4123b01ded6493a02b4cbf038928