how can I fix this display issue in *cider-error* buffer?

Unhandled clojure.lang.ExceptionInfo
   [38;5;32m-- [0m[38;5;45mRouter creation failed
   [0m[38;5;32m----------------------------------
   [0m[38;5;45mNO_SOURCE_FILE:6[0m [38;5;32m--[0m
   
   [38;5;253mRouter contains conflicting route paths:[0m

there is a way to fix it or at least ignore ansi and consider only text?

it’s exactly that it’s not doing anything with ansi escape codes. does your error handler add colours? I don’t know how to hide them in emacs, but your exception handler could/should not use colour unless it detects its output writer is a TTY

yeah, those make sense in a terminal setting, but I'd never include them in something that's meant to be used programmatically.

I can't remember if reitit was raising errors like this before. Will investigate their exception handler

looking at the code seems like this is the printing function https://github.com/metosin/reitit/blob/1ab075bd353966636f154ac36ae9b7990efeb008/modules/reitit-core/src/reitit/exception.cljc#L28 and nothing weird pops out

and my cider-print-fn is using 'pprintas default

found it, https://github.com/metosin/reitit/blob/1ab075bd353966636f154ac36ae9b7990efeb008/modules/reitit-dev/src/reitit/dev/pretty.cljc#L270 reitit pretty/exception namespace