bug: empty telescope preview if users don't call AerialXXX command first

[CharlesChiuGit]

Neovim version (nvim -v)

0.9.4

Operating system/version

macOS 14.1.1

Output of :AerialInfo

Aerial Info
-----------
Filetype: lua
Configured backends:
  treesitter (supported) (attached)
  lsp (supported)
  markdown (not supported) [Filetype is not markdown]
  man (not supported) [Filetype is not man]
Show symbols: Array, Boolean, Class, Constant, Constructor, Enum, Event, Field, File, Function, Interface, Key, Method, Module, Namespace, Null, Object, Operator, Package, Struct

Describe the bug

as title

Steps To Reproduce

1. open a lua file.
2. :Telescope aerial
   

vs

1. open a lua file.
2. open aerial side syntax tree (or other :AerialXXX command).
3. :Telescope aerial
   

Expected Behavior

non-empty telescope preview even without calling other first.

Minimal example file

telescope.lua:

...
		extensions = {
			aerial = {
				-- Display symbols as <root>.<parent>.<symbol>
				show_nesting = {
					["_"] = false, -- This key will be the default
					json = true, -- You can set the option for specific filetypes
					yaml = true,
				},
			},
		},
        require("telescope").load_extension("aerial")
...

aerial.lua:

return function()
	-- Call the setup function to change the default behavior
	require("modules.utils").load_plugin("aerial", {
		-- Priority list of preferred backends for aerial.
		-- This can be a filetype map (see :help aerial-filetype-map)
		backends = { "treesitter", "lsp", "markdown", "man" },

		layout = {
			-- These control the width of the aerial window.
			-- They can be integers or a float between 0 and 1 (e.g. 0.4 for 40%)
			-- min_width and max_width can be a list of mixed types.
			-- max_width = {40, 0.2} means "the lesser of 40 columns or 20% of total"
			max_width = { 40, 0.2 },
			width = nil,
			min_width = 30,

			-- key-value pairs of window-local options for aerial window (e.g. winhl)
			win_opts = {},

			-- Determines the default direction to open the aerial window. The 'prefer'
			-- options will open the window in the other direction *if* there is a
			-- different buffer in the way of the preferred direction
			-- Enum: prefer_right, prefer_left, right, left, float
			default_direction = "prefer_right",

			-- Determines where the aerial window will be opened
			--   edge   - open aerial at the far right/left of the editor
			--   window - open aerial to the right/left of the current window
			placement = "window",

			-- When the symbols change, resize the aerial window (within min/max constraints) to fit
			resize_to_content = true,

			-- Preserve window size equality with (:help CTRL-W_=)
			preserve_equality = false,
		},

		-- Determines how the aerial window decides which buffer to display symbols for
		--   window - aerial window will display symbols for the buffer in the window from which it was opened
		--   global - aerial window will display symbols for the current window
		attach_mode = "window",

		-- List of enum values that configure when to auto-close the aerial window
		--   unfocus       - close aerial when you leave the original source window
		--   switch_buffer - close aerial when you change buffers in the source window
		--   unsupported   - close aerial when attaching to a buffer that has no symbol source
		close_automatic_events = {},

		-- Keymaps in aerial window. Can be any value that `vim.keymap.set` accepts OR a table of keymap
		-- options with a `callback` (e.g. { callback = function() ... end, desc = "", nowait = true })
		-- Additionally, if it is a string that matches "actions.<name>",
		-- it will use the mapping at require("aerial.actions").<name>
		-- Set to `false` to remove a keymap
		keymaps = {
			["?"] = "actions.show_help",
			["g?"] = "actions.show_help",
			["<CR>"] = "actions.jump",
			["<2-LeftMouse>"] = "actions.jump",
			["<C-v>"] = "actions.jump_vsplit",
			["<C-s>"] = "actions.jump_split",
			["p"] = "actions.scroll",
			["<C-j>"] = "actions.down_and_scroll",
			["<C-k>"] = "actions.up_and_scroll",
			["{"] = "actions.prev",
			["}"] = "actions.next",
			["[["] = "actions.prev_up",
			["]]"] = "actions.next_up",
			["q"] = "actions.close",
			["o"] = "actions.tree_toggle",
			["za"] = "actions.tree_toggle",
			["O"] = "actions.tree_toggle_recursive",
			["zA"] = "actions.tree_toggle_recursive",
			["l"] = "actions.tree_open",
			["zo"] = "actions.tree_open",
			["L"] = "actions.tree_open_recursive",
			["zO"] = "actions.tree_open_recursive",
			["h"] = "actions.tree_close",
			["zc"] = "actions.tree_close",
			["H"] = "actions.tree_close_recursive",
			["zC"] = "actions.tree_close_recursive",
			["zr"] = "actions.tree_increase_fold_level",
			["zR"] = "actions.tree_open_all",
			["zm"] = "actions.tree_decrease_fold_level",
			["zM"] = "actions.tree_close_all",
			["zx"] = "actions.tree_sync_folds",
			["zX"] = "actions.tree_sync_folds",
		},

		-- When true, don't load aerial until a command or function is called
		-- Defaults to true, unless `on_attach` is provided, then it defaults to false
		lazy_load = true,

		-- Disable aerial on files with this many lines
		disable_max_lines = 10000,

		-- Disable aerial on files this size or larger (in bytes)
		disable_max_size = 2000000, -- Default 2MB

		-- A list of all symbols to display. Set to false to display all symbols.
		-- This can be a filetype map (see :help aerial-filetype-map)
		-- To see all available values, see :help SymbolKind
		filter_kind = {
			"Array",
			"Boolean",
			"Class",
			"Constant",
			"Constructor",
			"Enum",
			-- "EnumMember",
			"Event",
			"Field",
			"File",
			"Function",
			"Interface",
			"Key",
			"Method",
			"Module",
			"Namespace",
			"Null",
			-- "Number",
			"Object",
			"Operator",
			"Package",
			-- "Property",
			-- "String",
			"Struct",
			-- "TypeParameter",
			-- "Variable",
		},

		-- Determines line highlighting mode when multiple splits are visible.
		-- split_width   Each open window will have its cursor location marked in the
		--               aerial buffer. Each line will only be partially highlighted
		--               to indicate which window is at that location.
		-- full_width    Each open window will have its cursor location marked as a
		--               full-width highlight in the aerial buffer.
		-- last          Only the most-recently focused window will have its location
		--               marked in the aerial buffer.
		-- none          Do not show the cursor locations in the aerial window.
		highlight_mode = "split_width",

		-- Highlight the closest symbol if the cursor is not exactly on one.
		highlight_closest = true,

		-- Highlight the symbol in the source buffer when cursor is in the aerial win
		highlight_on_hover = false,

		-- When jumping to a symbol, highlight the line for this many ms.
		-- Set to false to disable
		highlight_on_jump = 300,

		-- Jump to symbol in source window when the cursor moves
		autojump = false,

		-- Define symbol icons. You can also specify "<Symbol>Collapsed" to change the
		-- icon when the tree is collapsed at that symbol, or "Collapsed" to specify a
		-- default collapsed icon. The default icon set is determined by the
		-- "nerd_font" option below.
		-- If you have lspkind-nvim installed, it will be the default icon set.
		-- This can be a filetype map (see :help aerial-filetype-map)
		icons = {},

		-- Control which windows and buffers aerial should ignore.
		-- Aerial will not open when these are focused, and existing aerial windows will not be updated
		ignore = {
			-- Ignore unlisted buffers. See :help buflisted
			unlisted_buffers = false,

			-- List of filetypes to ignore.
			filetypes = {},

			-- Ignored buftypes.
			-- Can be one of the following:
			-- false or nil - No buftypes are ignored.
			-- "special"    - All buffers other than normal, help and man page buffers are ignored.
			-- table        - A list of buftypes to ignore. See :help buftype for the
			--                possible values.
			-- function     - A function that returns true if the buffer should be
			--                ignored or false if it should not be ignored.
			--                Takes two arguments, `bufnr` and `buftype`.
			buftypes = "special",

			-- Ignored wintypes.
			-- Can be one of the following:
			-- false or nil - No wintypes are ignored.
			-- "special"    - All windows other than normal windows are ignored.
			-- table        - A list of wintypes to ignore. See :help win_gettype() for the
			--                possible values.
			-- function     - A function that returns true if the window should be
			--                ignored or false if it should not be ignored.
			--                Takes two arguments, `winid` and `wintype`.
			wintypes = "special",
		},

		-- Use symbol tree for folding. Set to true or false to enable/disable
		-- Set to "auto" to manage folds if your previous foldmethod was 'manual'
		-- This can be a filetype map (see :help aerial-filetype-map)
		manage_folds = true,

		-- When you fold code with za, zo, or zc, update the aerial tree as well.
		-- Only works when manage_folds = true
		link_folds_to_tree = false,

		-- Fold code when you open/collapse symbols in the tree.
		-- Only works when manage_folds = true
		link_tree_to_folds = true,

		-- Set default symbol icons to use patched font icons (see https://www.nerdfonts.com/)
		-- "auto" will set it to true if nvim-web-devicons or lspkind-nvim is installed.
		nerd_font = "auto",

		-- Call this function when aerial attaches to a buffer.
		-- on_attach = function(bufnr) end,

		-- Call this function when aerial first sets symbols on a buffer.
		-- on_first_symbols = function(bufnr) end,

		-- Automatically open aerial when entering supported buffers.
		-- This can be a function (see :help aerial-open-automatic)
		open_automatic = false,

		-- Run this command after jumping to a symbol (false will disable)
		post_jump_cmd = "normal! zz",

		-- Invoked after each symbol is parsed, can be used to modify the parsed item,
		-- or to filter it by returning false.
		--
		-- bufnr: a neovim buffer number
		-- item: of type aerial.Symbol
		-- ctx: a record containing the following fields:
		--   * backend_name: treesitter, lsp, man...
		--   * lang: info about the language
		--   * symbols?: specific to the lsp backend
		--   * symbol?: specific to the lsp backend
		--   * syntax_tree?: specific to the treesitter backend
		--   * match?: specific to the treesitter backend, TS query match
		-- post_parse_symbol = function(bufnr, item, ctx)
		-- 	return true
		-- end,

		-- Invoked after all symbols have been parsed and post-processed,
		-- allows to modify the symbol structure before final display
		--
		-- bufnr: a neovim buffer number
		-- items: a collection of aerial.Symbol items, organized in a tree,
		--        with 'parent' and 'children' fields
		-- ctx: a record containing the following fields:
		--   * backend_name: treesitter, lsp, man...
		--   * lang: info about the language
		--   * symbols?: specific to the lsp backend
		--   * syntax_tree?: specific to the treesitter backend
		-- post_add_all_symbols = function(bufnr, items, ctx)
		-- 	return items
		-- end,

		-- When true, aerial will automatically close after jumping to a symbol
		close_on_select = false,

		-- The autocmds that trigger symbols update (not used for LSP backend)
		update_events = "TextChanged,InsertLeave",

		-- Show box drawing characters for the tree hierarchy
		show_guides = false,

		-- Customize the characters used when show_guides = true
		guides = {
			-- When the child item has a sibling below it
			mid_item = "├─",
			-- When the child item is the last in the list
			last_item = "└─",
			-- When there are nested child guides to the right
			nested_top = "│ ",
			-- Raw indentation
			whitespace = "  ",
		},

		-- Set this function to override the highlight groups for certain symbols
		-- get_highlight = function(symbol, is_icon, is_collapsed)
		-- 	-- return "MyHighlight" .. symbol.kind
		-- end,

		-- Options for opening aerial in a floating win
		float = {
			-- Controls border appearance. Passed to nvim_open_win
			border = "rounded",

			-- Determines location of floating window
			--   cursor - Opens float on top of the cursor
			--   editor - Opens float centered in the editor
			--   win    - Opens float centered in the window
			relative = "cursor",

			-- These control the height of the floating window.
			-- They can be integers or a float between 0 and 1 (e.g. 0.4 for 40%)
			-- min_height and max_height can be a list of mixed types.
			-- min_height = {8, 0.1} means "the greater of 8 rows or 10% of total"
			max_height = 0.9,
			height = nil,
			min_height = { 8, 0.1 },

			-- override = function(conf, source_winid)
			-- 	-- This is the config that will be passed to nvim_open_win.
			-- 	-- Change values here to customize the layout
			-- 	return conf
			-- end,
		},

		-- Options for the floating nav windows
		nav = {
			border = "rounded",
			max_height = 0.9,
			min_height = { 10, 0.1 },
			max_width = 0.5,
			min_width = { 0.2, 20 },
			win_opts = {
				cursorline = true,
				winblend = 10,
			},
			-- Jump to symbol in source window when the cursor moves
			autojump = false,
			-- Show a preview of the code in the right column, when there are no child symbols
			preview = false,
			-- Keymaps in the nav window
			keymaps = {
				["<CR>"] = "actions.jump",
				["<2-LeftMouse>"] = "actions.jump",
				["<C-v>"] = "actions.jump_vsplit",
				["<C-s>"] = "actions.jump_split",
				["h"] = "actions.left",
				["l"] = "actions.right",
				["<C-c>"] = "actions.close",
			},
		},

		lsp = {
			-- Fetch document symbols when LSP diagnostics update.
			-- If false, will update on buffer changes.
			diagnostics_trigger_update = true,

			-- Set to false to not update the symbols when there are LSP errors
			update_when_errors = true,

			-- How long to wait (in ms) after a buffer change before updating
			-- Only used when diagnostics_trigger_update = false
			update_delay = 300,

			-- Map of LSP client name to priority. Default value is 10.
			-- Clients with higher (larger) priority will be used before those with lower priority.
			-- Set to -1 to never use the client.
			priority = {
				-- pyright = 10,
			},
		},

		treesitter = {
			-- How long to wait (in ms) after a buffer change before updating
			update_delay = 300,
		},

		markdown = {
			-- How long to wait (in ms) after a buffer change before updating
			update_delay = 300,
		},

		man = {
			-- How long to wait (in ms) after a buffer change before updating
			update_delay = 300,
		},
	})
end

plugin loading part:

completion["stevearc/aerial.nvim"] = {
	lazy = false,
	-- event = "LspAttach",
	config = require("completion.aerial"),
}

and

completion["stevearc/aerial.nvim"] = {
	lazy = true,
	event = "LspAttach",
	config = require("completion.aerial"),
}

both have the same issue, so I don't think it's about the lazy-loading strategy.

Minimal init.lua

No response

Additional context

https://github.com/ayamir/nvimdots/tree/refactor/use-aerial

We're preparing to replace symbol-outline.nvim with aerial.nvim and here's the pr.

[CharlesChiuGit]

set lazy_load = false in aerial config fixed the issue.