# HG changeset patch
# User Christian Brabandt <cb@256bit.org>
# Date 1704306602 -3600
# Node ID 48955338edb1046be0cd3050fb49af00d1df3c66
# Parent  c80bf1674767be529e68b53565ad30931a60b147
patch 9.1.0002: a closing fold expr, may start a new fold

Commit: https://github.com/vim/vim/commit/0689b870595c687a23e102913ce5037f65d03748
Author: Shota Nozaki <emonkak@gmail.com>
Date:   Wed Jan 3 19:18:43 2024 +0100

    patch 9.1.0002: a closing fold expr, may start a new fold

    Problem:  a closing fold expression may unexpectedly start a new fold
              when it should end a fold
              (reported by Shota Nozaki)
    Solution: if a fold hasn't started yet, do not immediately
              start a new fold with level 1
              (Shota Nozaki)

    fixes: #12768
    closes: #13748

    Signed-off-by: Shota Nozaki <emonkak@gmail.com>
    Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/fold.c b/src/fold.c
--- a/src/fold.c
+++ b/src/fold.c
@@ -3362,7 +3362,9 @@ foldlevelExpr(fline_T *flp)
 		  break;
 
 	// "<1", "<2", .. : end a fold with a certain level
-	case '<': flp->lvl_next = n - 1;
+	case '<': // To prevent an unexpected start of a new fold, the next
+		  // level must not exceed the level of the current fold.
+		  flp->lvl_next = MIN(flp->lvl, n - 1);
 		  flp->end = n;
 		  break;
 
diff --git a/src/testdir/test_fold.vim b/src/testdir/test_fold.vim
--- a/src/testdir/test_fold.vim
+++ b/src/testdir/test_fold.vim
@@ -1778,4 +1778,17 @@ func Test_foldexpr_return_empty_string()
   bwipe!
 endfunc
 
+" Make sure that when ending a fold that hasn't been started, it does not
+" start a new fold.
+func Test_foldexpr_end_fold()
+  new
+  setlocal foldmethod=expr
+  let &l:foldexpr = 'v:lnum == 2 ? "<2" : "="'
+  call setline(1, range(1, 3))
+  redraw
+  call assert_equal([0, 0, 0], range(1, 3)->map('foldlevel(v:val)'))
+
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2,
+/**/
     1,
 /**/
     0