Starting from "emacs -Q -f -eshell", type "echo $exec-path " (note
the trailing space), and then hit TAB. The result is this error:
pcomplete-match: Wrong type argument: stringp, ("/usr/bin" ...)
This is a regression from Emacs 28, and it looks like it's due to
'pcomplete-here-using-help' assuming that all the pcomplete args are
strings. However, 'exec-path' is a list (and Eshell reports it this
way to pcomplete), so the completion fails. I think all that's
necessary is checking that the pcomplete args are strings in
'pcomplete-here-using-help', but I know next to nothing about
pcomplete...
Adding Stefan, who should know more about pcomplete.
Stefan, any suggestions?