From 7b17eb4b063a234376c1ec909ee293e42cff290c Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Wed, 4 Jan 2023 14:31:49 +0000
Subject: [PATCH] patch 9.0.1143: invalid memory access with bad 'statusline'
 value

Problem:    Invalid memory access with bad 'statusline' value.
Solution:   Avoid going over the NUL at the end.
---
 src/buffer.c                    | 2 ++
 src/testdir/test_statusline.vim | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/src/buffer.c b/src/buffer.c
index 98568987894e..40168226160c 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4576,6 +4576,8 @@ build_stl_str_hl(
 #endif
 	if (vim_strchr(STL_ALL, *s) == NULL)
 	{
+	    if (*s == NUL)  // can happen with "%0"
+		break;
 	    s++;
 	    continue;
 	}
diff --git a/src/testdir/test_statusline.vim b/src/testdir/test_statusline.vim
index a829597655bf..23613bfed37b 100644
--- a/src/testdir/test_statusline.vim
+++ b/src/testdir/test_statusline.vim
@@ -436,6 +436,13 @@ func Test_statusline()
   set splitbelow&
 endfunc
 
+func Test_statusline_trailing_percent_zero()
+  " this was causing illegal memory access
+  set laststatus=2 stl=%!%0
+  call assert_fails('redraw', 'E15: Invalid expression: "%0"')
+  set laststatus& stl&
+endfunc
+
 func Test_statusline_visual()
   func CallWordcount()
     call wordcount()