Attached a better patch.

I need a little help, though. The following setting does not filter as intended, 
meaning I see the dired buffer for the current project and I also see the 
buffers `mu-project-buffer-p' should ignore:

(defun mu-project-buffer-p (buffer)
   "Check if BUFFER is NOT a member of `mu-ignored-buffers'."
   (not (seq-contains-p mu-ignored-buffers (buffer-name buffer) #'string-match-p)))

(setq-default project-switch-to-buffer-conditions '(mu-project-buffer-p
                                                     (not (derived-mode . 
comint-mode))))

However, this correctly hides the buffers specified in mu-ignored-buffers:

(setq-default project-switch-to-buffer-conditions '(mu-project-buffer-p)

-- 
Manuel Uberti
www.manueluberti.eu