fix(ui): close floating window on BufLeave event (#16664)

When buffer is visible in two splits simultaneously, BufHidden event is
not triggered, causing the floating window to remain on screen after
switching to another buffer.

Remove BufHidden event from close_events defaults, and close the window
if we changed the buffer to something other than the buffer that spawned
the floating window or the floating window buffer itself.

runtime/doc/lsp.txt

@@ -1377,18 +1377,6 @@ character_offset({bufnr}, {row}, {col})
                     (number, number) UTF-32 and UTF-16 index of the character
                     in line {row} column {col} in buffer {buf}
 
-                                        *vim.lsp.util.close_preview_autocmd()*
-close_preview_autocmd({events}, {winnr})
-                Creates autocommands to close a preview window when events
-                happen.
-
-                Parameters: ~
-                    {events}  (table) list of events
-                    {winnr}   (number) window id of preview window
-
-                See also: ~
-                    |autocmd-events|
-
                               *vim.lsp.util.convert_input_to_markdown_lines()*
 convert_input_to_markdown_lines({input}, {contents})
                 Converts any of `MarkedString` | `MarkedString[]` |

runtime/lua/vim/lsp/util.lua

@@ -1218,17 +1218,57 @@ function M.stylize_markdown(bufnr, contents, opts)
   return stripped
 end
 
+---@private
 --- Creates autocommands to close a preview window when events happen.
 ---
----@param events (table) list of events
----@param winnr (number) window id of preview window
+---@param events table list of events
+---@param winnr number window id of preview window
+---@param bufnrs table list of buffers where the preview window will remain visible
 ---@see |autocmd-events|
-function M.close_preview_autocmd(events, winnr)
+local function close_preview_autocmd(events, winnr, bufnrs)
+  local augroup = 'preview_window_'..winnr
+
+  -- close the preview window when entered a buffer that is not
+  -- the floating window buffer or the buffer that spawned it
+  vim.cmd(string.format([[
+    augroup %s
+      autocmd!
+      autocmd BufEnter * lua vim.lsp.util._close_preview_window(%d, {%s})
+    augroup end
+  ]], augroup, winnr, table.concat(bufnrs, ',')))
+
   if #events > 0 then
-    api.nvim_command("autocmd "..table.concat(events, ',').." <buffer> ++once lua pcall(vim.api.nvim_win_close, "..winnr..", true)")
+    vim.cmd(string.format([[
+      augroup %s
+        autocmd %s <buffer> lua vim.lsp.util._close_preview_window(%d)
+      augroup end
+    ]], augroup, table.concat(events, ','), winnr))
   end
 end
 
+---@private
+--- Closes the preview window
+---
+---@param winnr number window id of preview window
+---@param bufnrs table|nil optional list of ignored buffers
+function M._close_preview_window(winnr, bufnrs)
+  vim.schedule(function()
+    -- exit if we are in one of ignored buffers
+    if bufnrs and vim.tbl_contains(bufnrs, api.nvim_get_current_buf()) then
+      return
+    end
+
+    local augroup = 'preview_window_'..winnr
+    vim.cmd(string.format([[
+      augroup %s
+        autocmd!
+      augroup end
+      augroup! %s
+    ]], augroup, augroup))
+    pcall(vim.api.nvim_win_close, winnr, true)
+  end)
+end
+
 ---@internal
 --- Computes size of float needed to show contents (with optional wrapping)
 ---
@@ -1335,7 +1375,7 @@ function M.open_floating_preview(contents, syntax, opts)
   opts.wrap = opts.wrap ~= false -- wrapping by default
   opts.stylize_markdown = opts.stylize_markdown ~= false
   opts.focus = opts.focus ~= false
-  opts.close_events = opts.close_events or {"CursorMoved", "CursorMovedI", "BufHidden", "InsertCharPre"}
+  opts.close_events = opts.close_events or {"CursorMoved", "CursorMovedI", "InsertCharPre"}
 
   local bufnr = api.nvim_get_current_buf()
 
@@ -1404,7 +1444,7 @@ function M.open_floating_preview(contents, syntax, opts)
   api.nvim_buf_set_option(floating_bufnr, 'modifiable', false)
   api.nvim_buf_set_option(floating_bufnr, 'bufhidden', 'wipe')
   api.nvim_buf_set_keymap(floating_bufnr, "n", "q", "<cmd>bdelete<cr>", {silent = true, noremap = true, nowait = true})
-  M.close_preview_autocmd(opts.close_events, floating_winnr)
+  close_preview_autocmd(opts.close_events, floating_winnr, {floating_bufnr, bufnr})
 
   -- save focus_id
   if opts.focus_id then