investigating: https://github.com/tolitius/mount/issues/104

0. issue-104.clj

(ns issue-104.core
  (:require [mount.core :as mount :refer [defstate]]))

(mount/in-cljc-mode)

(defstate ^{:on-reload :noop} teststate
  :start "hi")

1. build.boot

(def +version+ "0.0.1")

(set-env!
  :source-paths #{"src"}
  :dependencies '[[org.clojure/clojure             "1.10.0"]
                  [org.clojure/tools.namespace     "0.2.11"]
                  [mount                           "0.1.15"]
                  [org.clojure/tools.logging       "0.4.1"]

                  ;; boot clj
                  [boot/core                       "2.8.2"   :scope "provided"]
                  [adzerk/bootlaces                "0.1.13"  :scope "test"]
                  [adzerk/boot-logservice          "1.2.0"   :scope "test"]
                  [adzerk/boot-test                "1.2.0"   :scope "test"]
                  [tolitius/boot-check             "0.1.11"  :scope "test"]])

(require '[adzerk.bootlaces :refer :all]
         '[adzerk.boot-test :as bt]
         '[adzerk.boot-logservice :as log-service]
         '[tolitius.boot-check :as check]
         '[clojure.tools.logging :as log])

(bootlaces! +version+)

(def log4b
  [:configuration
   [:appender {:name "STDOUT" :class "ch.qos.logback.core.ConsoleAppender"}
    [:encoder [:pattern "%-5level %logger{36} - %msg%n"]]]
   [:root {:level "TRACE"}
    [:appender-ref {:ref "STDOUT"}]]])

(deftask dev []
  (alter-var-root #'log/*logger-factory*
                  (constantly (log-service/make-factory log4b)))
  (repl))

2. repl.md

$ boot dev

boot.user=> (require '[mount.core :as mount]
                     '[issue-104.core :as iss]
                     '[clojure.tools.namespace.repl :as tn])

boot.user=> iss/teststate
#object[mount.core.DerefableState 0x7367eb6b {:status :pending, :val nil}]

boot.user=> (mount/start)
{:started ["#'issue-104.core/teststate"]}

boot.user=> iss/teststate
#object[mount.core.DerefableState 0x7367eb6b {:status :ready, :val "hi"}]

boot.user=> @iss/teststate
"hi"

boot.user=> (tn/refresh)
:reloading ()
:ok

boot.user=> iss/teststate
#object[mount.core.DerefableState 0x7367eb6b {:status :ready, :val "hi"}]

boot.user=> @iss/teststate
"hi"