vimscript - reliable way of checking win and buf type of a new window with autocommands

Question

So, I faced a need to check a type of a window and a buffer when entering a new window so I can do some stuff automatically depending on the types of aforementioned stuff.

For example, when quickfix is opened, I need to know that it is it, the same with command window, help, etc. Putting it in other words - I need to know when the new window opened is a regular window with a regular buffer in it.

The only ways that I wound was a combination of win_gettype() and &buftype options.

First thing I tried was an obvious WinEnter event, which didn't work properly as I couldn't check the type of a buffer.

Then, I tried BufEnter, but that wouldn't catch :split without arguments, apparently in a way similar to BufWinEnter. In addition, that wouldn't catch quickfix when it is opened for the first time and command.

So, coming to the question - is there any reliable way to validate window's and buffer's type automatically when a new window is opened without taking into account the way it was opened in? To summarize - there are two problems - 1) cannot catch a window at all if it is opened with :split without arguments, 2) cannot catch types reliably (see Edit 2).

EDIT 4

Well, with EDIT 3 taken into account, WinEnter works properly and as expected. But this is still a huge workaround. Will leave the question open in case anybody has an adequate solution.

EDIT 3

Well, I cannot see how to check things from EDIT 2 below upon window or buf entrance, but I guess it is possible to check them once again afterwords. I've come up with an idea to catch terminal with TerminalOpen, check command once again with CmdWinEnter, and fixquickfix problem with checking its' filetype with, well, FileType. These are huge workarounds, but I cannot see another way of solving this yet. Unfortunatelly, :split problem is still a thing.

EDIT 2

I've elaborated a bit on the main question and played a bit more with all this stuff. It seems like command line is caught. But terminal behavior is weird. So, behavior of different windows with WinEnter and BufEnter is as follows:

|Window    |WinEnter|BufEnter|
|:---------|:-------|:-------|
|quickfix  |   -    |+, 2    |
|command   |   -    |    +   |
|help      |   -    |    +   |  
|terminal  | +, 1   |+, 1    |

   

1 - but only if another terminal window is opened (the first one is not being caught);

2 - but fails for the first time after Vim startup.

Sorry for the table, it forces me to indent it for some reason, and it breaks all the pretty visuals on the page.

EDIT 1

Adding a snippet of code. The whole idea of what I am trying to do is storing an information about all the windows currently opened that are regular windows with regular buffers. Each time new window is opened or an old window is closed I need this info to be updated automatically. The core code is below:

function HandleNewWindow()
    let winid = win_getid()
    let wi = getwininfo(winid)[0]
    let bufnr = wi.bufnr

    if !CorrectBufAndWinTypes(bufnr, winid)
        return 1
    else
        " add winid to the list of regular windows' IDs
    endif
endfunction

function CorrectBufAndWinTypes(bufnr, winid)
    let wt = win_gettype(a:winid)
    let bt = getbufvar(a:bufnr, "&buftype")
    let wi = getwininfo(a:winid)[0]
    let is_terminal = wi.terminal
    let is_quickfix = wi.quickfix

    echom "WT - " wt "BT - " bt is_terminal is_quickfix

    if wt !=? "" || bt !=? "" || is_terminal || is_quickfix
        return 0
    else
        return 1
    endif
endfunction

" I was trying to handle it with the autocommands below:

" autocmd BufEnter * call HandleNewWindow()
"     cannot detect quickfix window at first try
"   (subsequent tries are positive, though)
"     can detect help, but only via &buftype

" autocmd WimEnter * call HandleNewWindow()
"     cannot detect quickfix at all
"     cannot detect help at all

"     both cannot handle command window (q:)

Answer 1

You shouldn't have to deal with buffers and thus use :help 'buftype'.

:help win_gettype() tells you if a window is:

• a popup window
• a preview window
• a command-line window

:help getwininfo() tells you if a window is:

• a quickfix window
• a terminal window

Having those related informations split between two inconsistently named functions is as ugly as can be but well…

Answer 2

You can check out :h :buffers which shows all buffers.

:buffers[!] [flags] where [flags] restricts the buffers to be listed. For example

" Show all active buffers
buffers! a

" Show regular active buffers
buffers a

" Show special(unlisted) active buffers
buffers au

You can also :filter buffers by displayed buffer name

filter /\.vim/ buffers a

Another way to get all buffers is getbufinfo() which provides more details.