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I have seen posts on the topic of getting "??" in the modeline instead of the line number. However despite my best efforts I can't get rid of the problem.
I have put those settings in my config:
(setq line-number-display-limit nil) (setq line-number-display-limit-width most-positive-fixnum)
I'm pretty sure they help, sometimes now it's OK. But at least half of the time it's not. It's funny, I made myself a test file and it's kind of randomly working or not...
spacemacs and put my config on github.
By the way, this is the relevant code in spacemacs if that helps...