fix: fix autoscroll in case of early terminal focus

[Run1e]

Fixes an issue where the CursorMoved autocmd will run before the on_lines handler and set autoscroll = false in the case of the user focusing on the terminal before any output, resulting in broken autoscrolling.

Discussion: #109 (reply in thread)

[igorlfs]

Hey, thanks for looking into this. Made a few important comments.

[Run1e]

Hi there again,

You're right my initial implementation was quite poorly tested, my bad. I've done a more thorough implementation which seems to fix all autoscrolling issues I've been seeing.

Most important changes are:

• Keep track of autoscrolling by individual term buffers
• Upon opening the console section, the autoscroll is re-applied if it was previously marked to be active (this seems to handle empty term buffers as well)

I also spotted a bug, namely that term buffers seem to be re-used, but the autoscroll setup seems to get called on each session restart, causing the InsertEnter/CursorMoved autocmd to be re-registered each time. I left a comment here: https://github.com/igorlfs/nvim-dap-view/pull/111/files#diff-665aacfce1a0455fca5c2033dcf97c838aafe2af15d4a75e0b588f5d10789f72R28

There's also no logic for clearing entries in the termbuf_is_autoscrolling table when buffers get deleted. I didn't find a logical place to put that, so I guess an autocmd is required. https://github.com/igorlfs/nvim-dap-view/pull/111/files#diff-665aacfce1a0455fca5c2033dcf97c838aafe2af15d4a75e0b588f5d10789f72R78

[igorlfs]

Thanks for going the extra mile to solve this issue!

Keep track of autoscrolling by individual term buffers

That's a really nice observation by the way!

[igorlfs]

Hey there,

I pushed some small fixes and merged soon after. Let me know if you run into any trouble with this newer version

[Run1e]

Hi there,

I'm having issues where opening the termbuf after lines have appeared causes the autoscroll to not work, as in it's stuck to the top.

I had this issue in my PR, and moving the vim.schedule to the scroll_to_bottom fixed it, and it does now too.

I.e.:

---@param winnr integer
---@param bufnr integer
M.scroll_to_bottom = function(winnr, bufnr)
    if util.is_win_valid(winnr) and util.is_buf_valid(bufnr) then
        vim.schedule(function()
            api.nvim_win_set_cursor(winnr, { api.nvim_buf_line_count(bufnr), 0 })
        end)

        termbuf_is_autoscrolling[bufnr] = true
    end
end

Not familiar enough with nvim internals to understand exactly what the root cause is here, but the above code (and removing vim.schedule from the on_lines callback) fixes it.

[igorlfs]

I'm having issues where opening the termbuf after lines have appeared causes the autoscroll to not work, as in it's stuck to the top.

Can you share an exact repro?

EDIT: I guess you're using a snippet similar to this one, with an early focus... I can actually repro with such a setup. I'll push your suggestion, because I see no reason not to. But I'm not 100% sure that's the way forward, with no regressions.

[igorlfs]

Done with 76f219c