NREPL errors in projects generated from this template

Hi there,

After a long absence from Clojure I thought I would take a look at Dmitri's book and I've hit a peculiar problem after generating a new project as per the instructions lein new luminus guestbook --template-version 3.91 -- +h2 +http-kit. (The problem I'm about to describe also affects the current template version and does not seem to have anything to do with h2 or http-kit).

I start a REPL with lein repl; this is using nrepl 0.8.3 and cider-nrepl 0.26.0 (the latest versions at time of writing). When I evaluate a simple form in Vim with fireplace it works fine. When I use Fireplace's Require! command (which boils down to (require :reload-all) I get errors from deep in nrepl.

user=> 2021-09-04 16:40:21,379 [nREPL-session-a02fb10d-98f1-4bf2-ac4f-51a6f8cde12c] ERROR guestbook.core - {:what :uncaught-exception, :exception #error {
 :cause No implementation of method: :send of protocol: #'nrepl.transport/Transport found for class: nrepl.transport.FnTransport
 :via
 [{:type java.lang.IllegalArgumentException
   :message No implementation of method: :send of protocol: #'nrepl.transport/Transport found for class: nrepl.transport.FnTransport
   :at [clojure.core$_cache_protocol_fn invokeStatic core_deftype.clj 583]}]
 :trace
 [[clojure.core$_cache_protocol_fn invokeStatic core_deftype.clj 583]
  [clojure.core$_cache_protocol_fn invoke core_deftype.clj 575]
  [nrepl.transport$eval33772$fn__33773$G__33763__33780 invoke transport.clj 17]
  [nrepl.middleware.print$send_streamed invokeStatic print.clj 136]
  [nrepl.middleware.print$send_streamed invoke print.clj 122]
  [nrepl.middleware.print$printing_transport$reify__15778 send print.clj 173]
  [nrepl.middleware.caught$caught_transport$reify__15813 send caught.clj 58]
  [nrepl.middleware.print$replying_PrintWriter$fn__15739 invoke print.clj 115]
  [nrepl.middleware.print.proxy$java.io.Writer$ff19274a write nil -1]
  [java.io.BufferedWriter flushBuffer BufferedWriter.java 120]
  [java.io.BufferedWriter flush BufferedWriter.java 256]
  [java.io.PrintWriter flush PrintWriter.java 396]
  [nrepl.middleware.interruptible_eval$evaluate invokeStatic interruptible_eval.clj 136]
  [nrepl.middleware.interruptible_eval$evaluate invoke interruptible_eval.clj 56]
  [nrepl.middleware.interruptible_eval$interruptible_eval$fn__15887$fn__15891 invoke interruptible_eval.clj 152]
  [clojure.lang.AFn run AFn.java 22]
  [nrepl.middleware.session$session_exec$main_loop__15954$fn__15958 invoke session.clj 202]
  [nrepl.middleware.session$session_exec$main_loop__15954 invoke session.clj 201]
  [clojure.lang.AFn run AFn.java 22]
  [java.lang.Thread run Thread.java 831]]}, :where Uncaught exception onnREPL-session-a02fb10d-98f1-4bf2-ac4f-51a6f8cde12c}

So why is the issue here and not in one of those other projects?

At first I assumed that my Vim setup had just rotted over the years. But a fresh install of emacs + spacemacs, jacking Cider into my repl process, had the same problems for the equivalent command.

I tried it on both my work (intel) macbook and my personal Linux machine - both exhibited the same error.

I then started trying it in different projects, using different templates. I have not yet found one that generates these errors apart from the luminus template.

Sorry if this is a misunderstanding on my part but I'm pretty much stumped at this point and googling the error message returns nothing relevant ...

luminus-framework / luminus-template

NREPL errors in projects generated from this template #546

So why is the issue here and not in one of those other projects?