From dd0dd4d78d65cf3a5a75dfceaf0dbf6f4d97501c Mon Sep 17 00:00:00 2001
From: Jan Edmund Lazo <jan.lazo@mail.utoronto.ca>
Date: Sun, 9 Sep 2018 13:22:10 -0400
Subject: vim-patch:8.0.1115: crash when using foldtextresult() recursively
 (#8972)

Problem:    Crash when using foldtextresult() recursively.
Solution:   Avoid recursive calls. (Yasuhiro Matsumoto, closes vim/vim#2098)
https://github.com/vim/vim/commit/495b7dd213e096361e6f15e7aed313c1d63d9d3e
---
 src/nvim/eval.c                |  7 +++++++
 src/nvim/testdir/test_fold.vim | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 309c0fc062..541a255dcc 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -8872,9 +8872,14 @@ static void f_foldtextresult(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   char_u buf[FOLD_TEXT_LEN];
   foldinfo_T foldinfo;
   int fold_count;
+  static bool entered = false;
 
   rettv->v_type = VAR_STRING;
   rettv->vval.v_string = NULL;
+  if (entered) {
+    return;  // reject recursive use
+  }
+  entered = true;
   linenr_T lnum = tv_get_lnum(argvars);
   // Treat illegal types and illegal string values for {lnum} the same.
   if (lnum < 0) {
@@ -8888,6 +8893,8 @@ static void f_foldtextresult(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     }
     rettv->vval.v_string = text;
   }
+
+  entered = false;
 }
 
 /*
diff --git a/src/nvim/testdir/test_fold.vim b/src/nvim/testdir/test_fold.vim
index 6917378890..e7d5a2ae2c 100644
--- a/src/nvim/testdir/test_fold.vim
+++ b/src/nvim/testdir/test_fold.vim
@@ -278,6 +278,7 @@ func Test_move_folds_around_manual()
   call assert_equal(0, foldlevel(6))
   call assert_equal(9, foldclosedend(7))
   call assert_equal([-1, 2, 2, 2, 2, -1, 7, 7, 7, -1], map(range(1, line('$')), 'foldclosed(v:val)'))
+
   %d
   " Ensure moving around the edges still works.
   call setline(1, PrepIndent("a") + repeat(["a"], 3) + ["\ta"])
@@ -634,3 +635,16 @@ func Test_fold_move()
   set fdm& sw& fdl&
   enew!
 endfunc
+
+func Test_foldtext_recursive()
+  new
+  call setline(1, ['{{{', 'some text', '}}}'])
+  setlocal foldenable foldmethod=marker foldtext=foldtextresult(v\:foldstart)
+  " This was crashing because of endless recursion.
+  2foldclose
+  redraw
+  call assert_equal(1, foldlevel(2))
+  call assert_equal(1, foldclosed(2))
+  call assert_equal(3, foldclosedend(2))
+  bwipe!
+endfunc
-- 
cgit