integrant-ref-with.clj

(defrecord RefWith [key opts]
  ig/RefLike
  (ref-key [_] key)
  (ref-resolve [_ config resolvef]
    (let [[k _] (first (ig/find-derived config key))
          config (update config k #(merge % opts))
          v (get (ig/init config [k]) k)]
      (resolvef k v))))

(defn ref-with [key opts]
  (->RefWith key opts))

(defmethod ig/init-key :test/ref-with [_ opts]
  opts)

(defmethod ig/init-key :component/basic [_ opts]
  (update opts :counter inc))

(defmethod ig/init-key :another/value [_ opts]
  opts)

(def s
  (ig/init {:test/ref-with {:age (ref-with :my/component {:counter 9999})}
            [:component/basic :my/component]
            {:counter 123
             :year 1992
             :value (ig/ref :another/value)}
            :another/value 1}))