Race condition with automatic agenda refresh when rescheduling from agenda buffer

[Maltimore]

Hi all,
I'm not filing this as an "official" issue, because it's a bug that only happens with a custom orgmode setup. Specifically, I'm using the following snippet suggested by @kristijanhusak in #656 to redo the agenda every time an org file is written:

vim.api.nvim_create_autocmd('BufWritePost', {
  pattern = '*.org',
  callback = function()
    local bufnr = vim.fn.bufnr('orgagenda') or -1
    if bufnr > -1 then
      require('orgmode').agenda:redo()
    end
  end
})

The issue is when I am in the agenda buffer and I re-schedule a task from there. In fact, it only happens if I re-schedule at least two things. I figured out that a race condition is happening: the above snippet causes a re-do of the agenda, but when re-scheduling from the agenda buffer, orgmode automatically causes a re-do as well, causing the agenda to be re-done twice. The following error occurs:

vim.schedule callback: unhandled promise rejection: { "...im_orgmode/lazy/orgmode/lua/orgmode/agenda/view/init.lua:71: Buffer is
 not 'modifiable'" }
stack traceback:
        [C]: in function 'error'
        .../nvim_orgmode/lazy/orgmode/lua/orgmode/utils/promise.lua:76: in function <.../nvim_orgmode/lazy/orgmode/lua/orgmode/u
tils/promise.lua:68>
        [C]: in function 'wait'
        /tmp/nvim_orgmode/lazy/orgmode/lua/orgmode/files/init.lua:343: in function 'ensure_loaded'
        /tmp/nvim_orgmode/lazy/orgmode/lua/orgmode/files/init.lua:149: in function 'all'
        ...orgmode/lazy/orgmode/lua/orgmode/agenda/types/agenda.lua:390: in function '_get_agenda_days'
        ...orgmode/lazy/orgmode/lua/orgmode/agenda/types/agenda.lua:244: in function 'render'
        /tmp/nvim_orgmode/lazy/orgmode/lua/orgmode/agenda/init.lua:77: in function 'render'
        /tmp/nvim_orgmode/lazy/orgmode/lua/orgmode/agenda/init.lua:303: in function </tmp/nvim_orgmode/lazy/orgmode/lua/orgmode/
agenda/init.lua:302>
        [C]: in function 'pcall'
        .../nvim_orgmode/lazy/orgmode/lua/orgmode/utils/promise.lua:20: in function 'pcall'
        .../nvim_orgmode/lazy/orgmode/lua/orgmode/utils/promise.lua:161: in function '_start_resolve'
        .../nvim_orgmode/lazy/orgmode/lua/orgmode/utils/promise.lua:151: in function '_resolve'
        .../nvim_orgmode/lazy/orgmode/lua/orgmode/utils/promise.lua:170: in function <.../nvim_orgmode/lazy/orgmode/lua/orgmode/
utils/promise.lua:169>

I believe what's happening is that the one agenda re-doing makes the agenda buffer modifiable, then the other re-doing tries to make it modifiabe (but it already is), and then the first re-doing makes it unmodifiable again, causing the second re-do to throw an error. Does anyone have an idea how to go about fixing this?

P.S.: Since there is clearly a lot of interest in having the agenda auto-update when org files are changed (see all the participants in #656), I think maybe we could think about robustly supporting agenda re-doing by default or at least as a configurable option?

[kristijanhusak]

Can you try modifying your snippet to this?

vim.api.nvim_create_autocmd('BufWritePost', {
  pattern = '*.org',
  callback = function(ev)
    if vim.b[ev.buffer].org_tmp_edit_window then
      return
    end
    local bufnr = vim.fn.bufnr('orgagenda') or -1
    if bufnr > -1 then
      require('orgmode').agenda:redo()
    end
  end
})

This should prevent the temporary buffer to trigger the redo, but when you edit a normal org file, it should work.

[Maltimore]

Yes! Wow, the magician strikes again! :)
Thanks a lot, this will be super helpful to me.

[Maltimore]

Strangely, there was a tiny bug in the above script, which nevertheless fixed my issue by erroring out of the redo early. But it caused another problem when saving .org files. It has to be ev.buf, not ev.buffer. The total patch for people who want to copy paste is

vim.api.nvim_create_autocmd('BufWritePost', {
  pattern = '*.org',
  callback = function(ev)
    if vim.b[ev.buf].org_tmp_edit_window then
      return
    end
    local bufnr = vim.fn.bufnr('orgagenda') or -1
    if bufnr > -1 then
      require('orgmode').agenda:redo()
    end
  end
})