Subject: bug#42017: 26.3; format-mode-line and %p

From: Mattias Engdegård <[email-masked]>
Date: Tue, 23 Jun 2020 15:12:49 +0200

tag 42017 notabug
close 42017
done

> (setq mode-line-format (:eval (format-mode-line "(%p)")))

The result of the form after :eval is the mode-line format string to use, not the final string itself.
What you observe is the effect of using "(25%)" (for example) as a mode-line format string: since "%)" is not a valid format specification, it produces no characters.

Thanks for reporting it just the same, and please do not let this dissuade you from reporting things you think aren't right in the future!