# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1643146203 -3600
# Node ID 123b0747fa10d1c41148f04aca88583ebd6acf08
# Parent  c4d24fdb7fe551c2c3c14d6c8ac2b901085ecae0
patch 8.2.4219: reading before the start of the line

Commit: https://github.com/vim/vim/commit/44db8213d38c39877d2148eff6a72f4beccfb94e
Author: Bram Moolenaar <Bram@vim.org>
Date:   Tue Jan 25 21:26:17 2022 +0000

    patch 8.2.4219: reading before the start of the line

    Problem:    Reading before the start of the line.
    Solution:   Check boundary before trying to read the character.

diff --git a/src/register.c b/src/register.c
--- a/src/register.c
+++ b/src/register.c
@@ -1474,7 +1474,7 @@ yank_copy_line(struct block_def *bd, lon
     {
 	int s = bd->textlen + bd->endspaces;
 
-	while (VIM_ISWHITE(*(bd->textstart + s - 1)) && s > 0)
+	while (s > 0 && VIM_ISWHITE(*(bd->textstart + s - 1)))
 	{
 	    s = s - (*mb_head_off)(bd->textstart, bd->textstart + s - 1) - 1;
 	    pnew--;
diff --git a/src/testdir/test_visual.vim b/src/testdir/test_visual.vim
--- a/src/testdir/test_visual.vim
+++ b/src/testdir/test_visual.vim
@@ -1247,6 +1247,13 @@ func Test_visual_put_blockedit_zy_and_zp
   bw!
 endfunc
 
+func Test_visual_block_yank_zy()
+  new
+  " this was reading before the start of the line
+  exe "norm o\<C-T>\<Esc>\<C-V>zy"
+  bwipe!
+endfunc
+
 func Test_visual_block_with_virtualedit()
   CheckScreendump
 
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4219,
+/**/
     4218,
 /**/
     4217,