vim-patch:8.2.4987: after deletion a small fold may be closable (#18683)

Problem:    After deletion a small fold may be closable.
Solution:   Check for a reverse range. (Brandon Simmons, closes vim/vim#10457)
https://github.com/vim/vim/commit/3fcccf94e8bc142d2c79c3b62087145896df6b36

1 files changed, 29 insertions, 0 deletions

diff --git a/src/nvim/testdir/test_fold.vim b/src/nvim/testdir/test_fold.vim
index b1d91fd879..da3e0ffc99 100644
--- a/src/nvim/testdir/test_fold.vim
+++ b/src/nvim/testdir/test_fold.vim
@@ -921,4 +921,33 @@ func Test_fold_split()
   bw!
 endfunc
 
+" Make sure that when you delete 1 line of a fold whose length is 2 lines, the
+" fold can't be closed since its length (1) is now less than foldminlines.
+func Test_indent_one_line_fold_close()
+  let lines =<< trim END
+    line 1
+      line 2
+      line 3
+  END
+
+  new
+  setlocal sw=2 foldmethod=indent
+  call setline(1, lines)
+  " open all folds, delete line, then close all folds
+  normal zR
+  3delete
+  normal zM
+  call assert_equal(-1, foldclosed(2)) " the fold should not be closed
+
+  " Now do the same, but delete line 2 this time; this covers different code.
+  " (Combining this code with the above code doesn't expose both bugs.)
+  1,$delete
+  call setline(1, lines)
+  normal zR
+  2delete
+  normal zM
+  call assert_equal(-1, foldclosed(2))
+  bw!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab