keymap.set in on_attach function is always called when buffer entered

[adoyle-h]

Describe the bug

Set buffer keymap in on_attach function will affect all buffers.

To Reproduce

require('aerial').setup({
  on_attach = function(bufnr)
    local aerial = require('aerial')
    require('notify')(string.format('buffer: %s', bufnr)) -- If notify not installed, use `print`

    -- vim.keymap.set('n', '<C-k>', function()
    -- 	aerial.up(-1)
    -- end, { buffer = bufnr })
    --
    -- vim.keymap.set('n', '<C-j>', function()
    -- 	aerial.up(1)
    -- end, { buffer = bufnr })
  end,
})

Screenshots

What to be expected

Only call on_attach after aerial window opened.

Set buffer keymap in on_attach function will only affect aerial buffer.

[stevearc]

Hmmm...perhaps this is a wording issue in the documentation. The on_attach function is called only for the source buffer, not the aerial buffer. It's intended to make it easy to set up keymaps for interacting with aerial once aerial has found a backend and attached to the buffer. If you want to set keymaps for aerial specifically, I'd recommend using a ftplugin/aerial.lua file, or by simply creating a FileType autocmd.

I may make it easier to change bindings in the aerial window in the future.

[adoyle-h]

I see. Thank you.

[adoyle-h]

@stevearc I have disabled all plugins but aerial. And set below codes.

vim.api.nvim_create_autocmd('FileType', {
	callback = function(args)
		if (args.match == 'aerial') then print('====', vim.loop.now()) end
	end,
})

I find that the print time is triggered when aerial window opened and cursor moved out aerial window.
But I expected it to print time only when aerial window opened. Is it a bug?

[stevearc]

Not strictly a bug, since the work it's doing should be idempotent, but unnecessary. I've pushed up a change that should prevent the duplicate calls.

Also, you can now set aerial-buffer keymaps in the call to setup(). Check the "keymaps" option.