Merge remote-tracking branch 'upstream/master' into mix_20240309HEADrahm

1 files changed, 647 insertions, 0 deletions

diff --git a/test/functional/plugin/lsp/folding_range_spec.lua b/test/functional/plugin/lsp/folding_range_spec.lua
new file mode 100644
index 0000000000..7e68a598d2
--- /dev/null
+++ b/test/functional/plugin/lsp/folding_range_spec.lua
@@ -0,0 +1,647 @@
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+local Screen = require('test.functional.ui.screen')
+local t_lsp = require('test.functional.plugin.lsp.testutil')
+
+local eq = t.eq
+local tempname = t.tmpname
+
+local clear_notrace = t_lsp.clear_notrace
+local create_server_definition = t_lsp.create_server_definition
+
+local api = n.api
+local exec_lua = n.exec_lua
+local insert = n.insert
+local command = n.command
+local feed = n.feed
+
+describe('vim.lsp.folding_range', function()
+  local text = [[// foldLevel() {{{2
+/// @return  fold level at line number "lnum" in the current window.
+static int foldLevel(linenr_T lnum)
+{
+  // While updating the folds lines between invalid_top and invalid_bot have
+  // an undefined fold level.  Otherwise update the folds first.
+  if (invalid_top == 0) {
+    checkupdate(curwin);
+  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {
+    return prev_lnum_lvl;
+  } else if (lnum >= invalid_top && lnum <= invalid_bot) {
+    return -1;
+  }
+
+  // Return quickly when there is no folding at all in this window.
+  if (!hasAnyFolding(curwin)) {
+    return 0;
+  }
+
+  return foldLevelWin(curwin, lnum);
+}]]
+
+  local result = {
+    {
+      endLine = 19,
+      kind = 'region',
+      startCharacter = 1,
+      startLine = 3,
+    },
+    {
+      endCharacter = 2,
+      endLine = 7,
+      kind = 'region',
+      startCharacter = 25,
+      startLine = 6,
+    },
+    {
+      endCharacter = 2,
+      endLine = 9,
+      kind = 'region',
+      startCharacter = 55,
+      startLine = 8,
+    },
+    {
+      endCharacter = 2,
+      endLine = 11,
+      kind = 'region',
+      startCharacter = 58,
+      startLine = 10,
+    },
+    {
+      endCharacter = 2,
+      endLine = 16,
+      kind = 'region',
+      startCharacter = 31,
+      startLine = 15,
+    },
+    {
+      endCharacter = 68,
+      endLine = 1,
+      kind = 'comment',
+      startCharacter = 2,
+      startLine = 0,
+    },
+    {
+      endCharacter = 64,
+      endLine = 5,
+      kind = 'comment',
+      startCharacter = 4,
+      startLine = 4,
+    },
+  }
+
+  local bufnr ---@type integer
+  local client_id ---@type integer
+
+  clear_notrace()
+  before_each(function()
+    clear_notrace()
+
+    exec_lua(create_server_definition)
+    bufnr = n.api.nvim_get_current_buf()
+    client_id = exec_lua(function()
+      _G.server = _G._create_server({
+        capabilities = {
+          foldingRangeProvider = true,
+        },
+        handlers = {
+          ['textDocument/foldingRange'] = function(_, _, callback)
+            callback(nil, result)
+          end,
+        },
+      })
+
+      vim.api.nvim_win_set_buf(0, bufnr)
+
+      return vim.lsp.start({ name = 'dummy', cmd = _G.server.cmd })
+    end)
+    command('set foldmethod=expr foldcolumn=1 foldlevel=999')
+    insert(text)
+  end)
+  after_each(function()
+    api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
+  end)
+
+  describe('setup()', function()
+    ---@type integer
+    local bufnr_set_expr
+    ---@type integer
+    local bufnr_never_set_expr
+
+    local function buf_autocmd_num(bufnr_to_check)
+      return exec_lua(function()
+        return #vim.api.nvim_get_autocmds({ buffer = bufnr_to_check, event = 'LspNotify' })
+      end)
+    end
+
+    before_each(function()
+      command([[setlocal foldexpr=v:lua.vim.lsp.foldexpr()]])
+      exec_lua(function()
+        bufnr_set_expr = vim.api.nvim_create_buf(true, false)
+        vim.api.nvim_set_current_buf(bufnr_set_expr)
+      end)
+      insert(text)
+      command('write ' .. tempname(false))
+      command([[setlocal foldexpr=v:lua.vim.lsp.foldexpr()]])
+      exec_lua(function()
+        bufnr_never_set_expr = vim.api.nvim_create_buf(true, false)
+        vim.api.nvim_set_current_buf(bufnr_never_set_expr)
+      end)
+      insert(text)
+      api.nvim_win_set_buf(0, bufnr_set_expr)
+    end)
+
+    it('only create event hooks where foldexpr has been set', function()
+      eq(1, buf_autocmd_num(bufnr))
+      eq(1, buf_autocmd_num(bufnr_set_expr))
+      eq(0, buf_autocmd_num(bufnr_never_set_expr))
+    end)
+
+    it('does not create duplicate event hooks after reloaded', function()
+      command('edit')
+      eq(1, buf_autocmd_num(bufnr_set_expr))
+    end)
+
+    it('cleans up event hooks when buffer is unloaded', function()
+      command('bdelete')
+      eq(0, buf_autocmd_num(bufnr_set_expr))
+    end)
+  end)
+
+  describe('expr()', function()
+    --- @type test.functional.ui.screen
+    local screen
+    before_each(function()
+      screen = Screen.new(80, 45)
+      screen:set_default_attr_ids({
+        [1] = { background = Screen.colors.Grey, foreground = Screen.colors.DarkBlue },
+        [2] = { bold = true, foreground = Screen.colors.Blue1 },
+        [3] = { bold = true, reverse = true },
+        [4] = { reverse = true },
+      })
+      command([[set foldexpr=v:lua.vim.lsp.foldexpr()]])
+      command([[split]])
+    end)
+
+    it('can compute fold levels', function()
+      ---@type table<integer, string>
+      local foldlevels = {}
+      for i = 1, 21 do
+        foldlevels[i] = exec_lua('return vim.lsp.foldexpr(' .. i .. ')')
+      end
+      eq({
+        [1] = '>1',
+        [2] = '<1',
+        [3] = '0',
+        [4] = '>1',
+        [5] = '>2',
+        [6] = '<2',
+        [7] = '>2',
+        [8] = '<2',
+        [9] = '>2',
+        [10] = '<2',
+        [11] = '>2',
+        [12] = '<2',
+        [13] = '1',
+        [14] = '1',
+        [15] = '1',
+        [16] = '>2',
+        [17] = '<2',
+        [18] = '1',
+        [19] = '1',
+        [20] = '<1',
+        [21] = '0',
+      }, foldlevels)
+    end)
+
+    it('updates folds in all windows', function()
+      screen:expect({
+        grid = [[
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:[No Name] [+]                                                                   }|
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{4:[No Name] [+]                                                                   }|
+                                                                                |
+  ]],
+      })
+    end)
+
+    it('persists wherever foldexpr is set', function()
+      command([[setlocal foldexpr=]])
+      feed('<C-w><C-w>zx')
+      screen:expect({
+        grid = [[
+{1: }// foldLevel() {{{2                                                            |
+{1: }/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1: }{                                                                              |
+{1: }  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1: }  // an undefined fold level.  Otherwise update the folds first.               |
+{1: }  if (invalid_top == 0) {                                                      |
+{1: }    checkupdate(curwin);                                                       |
+{1: }  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1: }    return prev_lnum_lvl;                                                      |
+{1: }  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1: }    return -1;                                                                 |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  // Return quickly when there is no folding at all in this window.            |
+{1: }  if (!hasAnyFolding(curwin)) {                                                |
+{1: }    return 0;                                                                  |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{4:[No Name] [+]                                                                   }|
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:[No Name] [+]                                                                   }|
+                                                                                |
+  ]],
+      })
+    end)
+
+    it('synchronizes changed rows with their previous foldlevels', function()
+      command('1,2d')
+      screen:expect({
+        grid = [[
+{1: }^static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{2:~                                                                               }|*2
+{3:[No Name] [+]                                                                   }|
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{2:~                                                                               }|*2
+{4:[No Name] [+]                                                                   }|
+                                                                                |
+]],
+      })
+    end)
+
+    it('clears folds when sole client detaches', function()
+      exec_lua(function()
+        vim.lsp.buf_detach_client(bufnr, client_id)
+      end)
+      screen:expect({
+        grid = [[
+{1: }// foldLevel() {{{2                                                            |
+{1: }/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1: }{                                                                              |
+{1: }  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1: }  // an undefined fold level.  Otherwise update the folds first.               |
+{1: }  if (invalid_top == 0) {                                                      |
+{1: }    checkupdate(curwin);                                                       |
+{1: }  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1: }    return prev_lnum_lvl;                                                      |
+{1: }  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1: }    return -1;                                                                 |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  // Return quickly when there is no folding at all in this window.            |
+{1: }  if (!hasAnyFolding(curwin)) {                                                |
+{1: }    return 0;                                                                  |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:[No Name] [+]                                                                   }|
+{1: }// foldLevel() {{{2                                                            |
+{1: }/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1: }{                                                                              |
+{1: }  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1: }  // an undefined fold level.  Otherwise update the folds first.               |
+{1: }  if (invalid_top == 0) {                                                      |
+{1: }    checkupdate(curwin);                                                       |
+{1: }  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1: }    return prev_lnum_lvl;                                                      |
+{1: }  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1: }    return -1;                                                                 |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  // Return quickly when there is no folding at all in this window.            |
+{1: }  if (!hasAnyFolding(curwin)) {                                                |
+{1: }    return 0;                                                                  |
+{1: }  }                                                                            |
+{1: }                                                                               |
+{1: }  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{4:[No Name] [+]                                                                   }|
+                                                                                |
+  ]],
+      })
+    end)
+
+    it('remains valid after the client re-attaches.', function()
+      exec_lua(function()
+        vim.lsp.buf_detach_client(bufnr, client_id)
+        vim.lsp.buf_attach_client(bufnr, client_id)
+      end)
+      screen:expect({
+        grid = [[
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:[No Name] [+]                                                                   }|
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }}                                                                              |
+{4:[No Name] [+]                                                                   }|
+                                                                                |
+  ]],
+      })
+    end)
+  end)
+
+  describe('foldtext()', function()
+    --- @type test.functional.ui.screen
+    local screen
+    before_each(function()
+      screen = Screen.new(80, 23)
+      screen:set_default_attr_ids({
+        [1] = { background = Screen.colors.Grey, foreground = Screen.colors.DarkBlue },
+        [2] = { foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey },
+        [3] = { bold = true, foreground = Screen.colors.Blue1 },
+        [4] = { bold = true, reverse = true },
+        [5] = { reverse = true },
+      })
+      command(
+        [[set foldexpr=v:lua.vim.lsp.foldexpr() foldtext=v:lua.vim.lsp.foldtext() foldlevel=1]]
+      )
+    end)
+
+    it('shows the first folded line if `collapsedText` does not exist', function()
+      screen:expect({
+        grid = [[
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:+}{2:  // While updating the folds lines between invalid_top and invalid_bot have···}|
+{1:+}{2:  if (invalid_top == 0) {······················································}|
+{1:+}{2:  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {························}|
+{1:+}{2:  } else if (lnum >= invalid_top && lnum <= invalid_bot) {·····················}|
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:+}{2:  if (!hasAnyFolding(curwin)) {················································}|
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:~                                                                               }|*6
+                                                                                |
+  ]],
+      })
+    end)
+  end)
+
+  describe('foldclose()', function()
+    --- @type test.functional.ui.screen
+    local screen
+    before_each(function()
+      screen = Screen.new(80, 23)
+      screen:set_default_attr_ids({
+        [1] = { background = Screen.colors.Grey, foreground = Screen.colors.DarkBlue },
+        [2] = { foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey },
+        [3] = { bold = true, foreground = Screen.colors.Blue1 },
+        [4] = { bold = true, reverse = true },
+        [5] = { reverse = true },
+      })
+      command([[set foldexpr=v:lua.vim.lsp.foldexpr()]])
+    end)
+
+    it('closes all folds of one kind immediately', function()
+      exec_lua(function()
+        vim.lsp.foldclose('comment')
+      end)
+      screen:expect({
+        grid = [[
+{1:+}{2:+--  2 lines: foldLevel()······················································}|
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:+}{2:+---  2 lines: While updating the folds lines between invalid_top and invalid_b}|
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:~                                                                               }|*3
+                                                                                |
+  ]],
+      })
+    end)
+
+    it('closes the smallest fold first', function()
+      exec_lua(function()
+        vim.lsp.foldclose('region')
+      end)
+      screen:expect({
+        grid = [[
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:+}{2:+-- 17 lines: {································································}|
+{1: }^}                                                                              |
+{3:~                                                                               }|*17
+                                                                                |
+  ]],
+      })
+      command('4foldopen')
+      screen:expect({
+        grid = [[
+{1:-}// foldLevel() {{{2                                                            |
+{1:│}/// @return  fold level at line number "lnum" in the current window.           |
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:-}  // While updating the folds lines between invalid_top and invalid_bot have   |
+{1:2}  // an undefined fold level.  Otherwise update the folds first.               |
+{1:+}{2:+---  2 lines: if (invalid_top == 0) {·········································}|
+{1:+}{2:+---  2 lines: } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {···········}|
+{1:+}{2:+---  2 lines: } else if (lnum >= invalid_top && lnum <= invalid_bot) {········}|
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:+}{2:+---  2 lines: if (!hasAnyFolding(curwin)) {···································}|
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:~                                                                               }|*5
+                                                                                |
+  ]],
+      })
+    end)
+
+    it('is defered when the buffer is not up-to-date', function()
+      exec_lua(function()
+        vim.lsp.foldclose('comment')
+        vim.lsp.util.buf_versions[bufnr] = 0
+      end)
+      screen:expect({
+        grid = [[
+{1:+}{2:+--  2 lines: foldLevel()······················································}|
+{1: }static int foldLevel(linenr_T lnum)                                            |
+{1:-}{                                                                              |
+{1:+}{2:+---  2 lines: While updating the folds lines between invalid_top and invalid_b}|
+{1:-}  if (invalid_top == 0) {                                                      |
+{1:2}    checkupdate(curwin);                                                       |
+{1:-}  } else if (lnum == prev_lnum && prev_lnum_lvl >= 0) {                        |
+{1:2}    return prev_lnum_lvl;                                                      |
+{1:-}  } else if (lnum >= invalid_top && lnum <= invalid_bot) {                     |
+{1:2}    return -1;                                                                 |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  // Return quickly when there is no folding at all in this window.            |
+{1:-}  if (!hasAnyFolding(curwin)) {                                                |
+{1:2}    return 0;                                                                  |
+{1:│}  }                                                                            |
+{1:│}                                                                               |
+{1:│}  return foldLevelWin(curwin, lnum);                                           |
+{1: }^}                                                                              |
+{3:~                                                                               }|*3
+                                                                                |
+  ]],
+      })
+    end)
+  end)
+end)