Notify on non-zero exit codes

[musjj]

formatters silently fails on non-zero exit codes by default, which makes it hard to figure out if things went wrong.
I can set the source's ignore_stderr to false, and it seems that it's close to what I'm looking for, but what happens is that the source will stop working after it receives an error.
Is there any way to have a notification when a source encounters an error, without having the source crash?
I can also of course look at the log file, but it's obviously less convenient.

[musjj]

I guess this is the cause:

null-ls.nvim/lua/null-ls/generators.lua

Lines 93 to 97 in a75bba0

	if not ok then
	log:warn("failed to run generator: " .. results)
	generator._failed = true
	return
	end

null-ls.nvim/lua/null-ls/sources.lua

Lines 100 to 106 in a75bba0

	M.is_available = function(source, filetype, method)
	if source._disabled or source.generator._failed then
	return false
	end
	return (not filetype or matches_filetype(source, filetype)) and (not method or matches_method(source, method))
	end

Once a generator failed, it effectively becomes disabled.
Is there a reason for this behavior?

[jose-elias-alvarez]

This is deliberate and I'm not likely to change it at this point, simply because a lot of users have formatting on save set up and it could be annoying to get notified each time a formatter fails. I'd consider this a more niche use case, but you can achieve this by overriding set_exit_code and logging out stderr (example).

[musjj]

Thanks for the hint. I'm using this little hack to apply it to all formatters, and it seem to work fine for now:

require("null-ls.helpers.formatter_factory")
local formatter_factory = package.loaded["null-ls.helpers.formatter_factory"]
package.loaded["null-ls.helpers.formatter_factory"] = function(opts)
  local check_exit_code = opts.check_exit_code
  local checker
  if type(check_exit_code) == "table" then
    checker = function(code) return vim.tbl_contains(check_exit_code, code) end
  elseif type(check_exit_code) == "function" then
    checker = function(code, stderr) return check_exit_code(code, stderr) end
  else
    checker = function(code) return code == 0 end
  end
  opts.check_exit_code = function(code, stderr)
    local status = checker(code, stderr)
    if not status then
      vim.notify(stderr, vim.log.levels.ERROR)
    end
    return status
  end
  return formatter_factory(opts)
end