From d6211a52ab9f53b82f884561ed43d2fe4d24ff7d Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sat, 18 Jun 2022 19:48:14 +0100
Subject: [PATCH] patch 8.2.5126: substitute may overrun destination buffer

Problem:    Substitute may overrun destination buffer.
Solution:   Disallow switching buffers in a substitute expression.
---
 src/ex_docmd.c                  |  7 ++++---
 src/testdir/test_substitute.vim | 13 +++++++++++++
 src/version.c                   |  2 ++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index fed9330b52e92..1185cd1550a61 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -7138,9 +7138,10 @@ do_exedit(
 #endif
 	    )
     {
-	// Can't edit another file when "curbuf_lock" is set.  Only ":edit"
-	// can bring us here, others are stopped earlier.
-	if (*eap->arg != NUL && curbuf_locked())
+	// Can't edit another file when "textlock" or "curbuf_lock" is set.
+	// Only ":edit" or ":script" can bring us here, others are stopped
+	// earlier.
+	if (*eap->arg != NUL && text_or_buf_locked())
 	    return;
 
 	n = readonlymode;
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 46ea955131928..c056fa9656929 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -1063,6 +1063,19 @@ func Test_sub_open_cmdline_win()
   call delete('Xresult')
 endfunc
 
+" This was editing a script file from the expression
+func Test_sub_edit_scriptfile()
+  new
+  norm o0000000000000000000000000000000000000000000000000000
+  func EditScript()
+    silent! scr! Xfile
+  endfunc
+  s/\%')/\=EditScript()
+
+  delfunc EditScript
+  bwipe!
+endfunc
+
 " Test for the 2-letter and 3-letter :substitute commands
 func Test_substitute_short_cmd()
   new
diff --git a/src/version.c b/src/version.c
index 82ac4eaf2dd99..2f397ae315f7c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5126,
 /**/
     5125,
 /**/