bug: {} should be considered "no result" when returned from parser in on_output_parse

[jerri]

Neovim version (nvim -v)

v0.11.6

Operating system/version

MacOS 26.2

Describe the bug

I tried to create a parser which only returns a result when certain strings are found in the output of a task. This way I wanted to be able to only open the output with open_output and on_result = "always" when there is actually interesting stuff happening.

Unfortunately, when I try to return {} from get_result in my parser, the on_result still gets triggered and the output is shown. I consider this a bug, because this way you can't not trigger on_result with on_output_parse. Returning nil doesn't work either, as on_pre_result expects the result to be a table, otherwise you get an error message in overseer.log.

I was able to work around the situation with if_diagnostics and just returning something in the diagnostics key, but I think returning {} as no result would make more sense.

I tried to find the issue in the code, but I am not sure why it happens. According to the code in task.lua, {} should actually be considered no result. Not sure though, what is happening.

What is the severity of this bug?

tolerable (can work around it)

Steps To Reproduce

With a parser like

local error_parser = {
_error_found = false
parse = function (self, line)
if line.match("Error") then
self._error_found = true
end
end,
get_result = function ()
if self._error_found then
return { error_found = true }
end
return {}
end,
reset = function ()
self._error_found = false
end
}

and used within on_output_parse as parser. Then open_output gets triggered when on_result = "always".

Expected Behavior

{} should be considered no result and open_output should not be triggered.

Minimal example file

No response

Minimal init.lua

-- DO NOT change the paths and don't remove the colorscheme
local root = vim.fn.fnamemodify("./.repro", ":p")

-- set stdpaths to use .repro
for _, name in ipairs({ "config", "data", "state", "cache" }) do
  vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. "/" .. name
end

-- bootstrap lazy
local lazypath = root .. "/plugins/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  vim.fn.system({
    "git",
    "clone",
    "--filter=blob:none",
    "--single-branch",
    "https://github.com/folke/lazy.nvim.git",
    lazypath,
  })
end
vim.opt.runtimepath:prepend(lazypath)

-- install plugins
local plugins = {
  "folke/tokyonight.nvim",
  { "stevearc/dressing.nvim", config = true },
  {
    "stevearc/overseer.nvim",
    config = function()
      require("overseer").setup({
        -- add your overseer config here
      })
    end,
  },
  -- add any other plugins here
}
require("lazy").setup(plugins, {
  root = root .. "/plugins",
})

vim.cmd.colorscheme("tokyonight")
-- add anything else here

Additional context

No response