Set winbar throws not enough space error even when there's space.

[shadmansaleh]

Neovim version (nvim -v)

0.8.0 commit 1f1863e

Vim (not Nvim) behaves the same?

no

Operating system/version

Arch linux

Terminal name/version

Kitty terminal

$TERM environment variable

screen-256color

Installation

build from repo

How to reproduce the issue

Reproduction steps

-- file: minimal_reproduce.lua
local win = vim.api.nvim_get_current_win()
vim.wo[win].winbar = '%f'

local grp = vim.api.nvim_create_augroup('asdf', {clear=true})
vim.api.nvim_create_autocmd('WinEnter', {
  group = grp,
  pattern = '*',
  desc = 'winbar crash?',
  callback = function ()
    vim.wo[win].winbar = '%f'
  end
})

local buf = vim.api.nvim_create_buf(false, true)
vim.api.nvim_open_win(buf, true, {
  relative = "win",
  win = win,
  border = 'single',
  col = 1,
  row = 1,
  height = 1,
  width = 40,
})

nvim --clean minimal_reproduce.lua
:lua require('minimal_reproduce')

Things to note

• A winbar on current win is already set.
• We are trying to set winbar of previous win while entering the float of height 1 in auto command context.

Expected behavior

No error should be thrown as the original window has enough space in it to draw winbar.

Actual behavior

It throws following error

Error detected while processing WinEnter Autocommands for "*":
Error executing lua callback: ./minimal_reproduce.lua:10: Vim:E36: Not enough room
stack traceback:
        [C]: in function '__newindex'
        ./minimal_reproduce.lua:10: in function <./minimal_reproduce.lua:9>
        [C]: in function 'nvim_open_win'
        ./minimal_reproduce.lua:15: in main chunk
        [C]: in function 'require'
        [string ":lua"]:1: in main chunk

Speculations

It seems nvim is trying to draw winbar on the float even though winbar option in that window is empty . This can actually be seen if you open the float with height 2 the float buffer starts after an empty line.

@famiu any clue ?

[famiu]

There isn't enough room on the floating window since it's only a single row and the only row cannot be a winbar, and winbar will not resize float windows by its own volition

[zeertzjq]

When a floating window is created its 'winbar' option is not cleared.

[shadmansaleh]

There isn't enough room on the floating window since it's only a single row and the only row cannot be a winbar, and winbar will not resize float windows by its own volition

You're missing the point . The floating window isn't suppose to have a winbar . The winbar option is set as window local option on a different window.

[famiu]

It seems like this is still intended behavior since floating windows are supposed to act like split windows but just floating, so it's desired for them to inherit all options from the last window.

[shadmansaleh]

In that case why doesn't winbar get set if the autocommand isn't there ?

-- file: minimal_reproduce.lua
local win = vim.api.nvim_get_current_win()
vim.wo[win].winbar = '%f'

local buf = vim.api.nvim_create_buf(false, true)
vim.api.nvim_open_win(buf, true, {
  relative = "win",
  win = win,
  border = 'single',
  col = 1,
  row = 1,
  height = 1,
  width = 40,
})

This should throw error too right ?

Note floats with height 1 is a lot more common then splits with height 1. It's not very likely you'll hit not enough space error with splits but you'll regularly hit it with floats as a ton of plugins use single height floats (I think lsp & diagnostic code in core does too). And if it's the default behavior then it's impossible handle this error as nvim_open_win will be throwing error about not having enough space even before anything can clear that inherited winbar .

Winbar in floats are already an exception as in they don't render globar winbar option (BTW why was this decision made ?) I think it's better if floats don't inherit winbar option.

[zeertzjq]

A workaround is to switch to the floating window later, after it's buffer is set, by passing false as the second argument of nvim_open_win and using nvim_set_current_win later instead:

-- file: minimal_reproduce.lua
local win = vim.api.nvim_get_current_win()
vim.wo[win].winbar = '%f'

local grp = vim.api.nvim_create_augroup('asdf', {clear=true})
vim.api.nvim_create_autocmd('WinEnter', {
  group = grp,
  pattern = '*',
  desc = 'winbar crash?',
  callback = function ()
    vim.wo[win].winbar = '%f'
  end
})

local buf = vim.api.nvim_create_buf(false, true)
vim.api.nvim_set_current_win(vim.api.nvim_open_win(buf, false, {
  relative = "win",
  win = win,
  border = 'single',
  col = 1,
  row = 1,
  height = 1,
  width = 40,
}))

This workaround works for WinEnter, BufEnter, BufWinEnter, WinLeave etc., but not BufLeave.