From 6e28703a8e41f775f64e442c5d11ce1ff599aa3f Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sat, 12 Feb 2022 15:42:18 +0000
Subject: [PATCH] patch 8.2.4359: crash when repeatedly using :retab

Problem:    crash when repeatedly using :retab.
Solution:   Bail out when the line is getting too long.
---
 src/indent.c               |  5 +++++
 src/testdir/test_retab.vim | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/src/indent.c b/src/indent.c
index e8e93b9..075802c 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -1689,6 +1689,11 @@ ex_retab(exarg_T *eap)
 	    if (ptr[col] == NUL)
 		break;
 	    vcol += chartabsize(ptr + col, (colnr_T)vcol);
+	    if (vcol >= MAXCOL)
+	    {
+		emsg(_(e_resulting_text_too_long));
+		break;
+	    }
 	    if (has_mbyte)
 		col += (*mb_ptr2len)(ptr + col);
 	    else
diff --git a/src/testdir/test_retab.vim b/src/testdir/test_retab.vim
index e7b8946..5376f92 100644
--- a/src/testdir/test_retab.vim
+++ b/src/testdir/test_retab.vim
@@ -69,6 +69,8 @@ func Test_retab()
   call assert_equal("    a       b        c    ",         Retab('!', 3))
   call assert_equal("    a       b        c    ",         Retab('',  5))
   call assert_equal("    a       b        c    ",         Retab('!', 5))
+
+  set tabstop& expandtab&
 endfunc
 
 func Test_retab_error()
@@ -78,3 +80,21 @@ func Test_retab_error()
   call assert_fails('ret 10000', 'E475:')
   call assert_fails('ret 80000000000000000000', 'E475:')
 endfunc
+
+func Test_retab_endless()
+  new
+  call setline(1, "\t0\t")
+  let caught = 'no'
+  try
+    while 1
+      set ts=4000
+      retab 4
+    endwhile
+  catch /E1240/
+    let caught = 'yes'
+  endtry
+  bwipe!
+  set tabstop&
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
-- 
2.27.0