om.next transform-reads issue

transform-reads-missing-reads.clj

;; Issue with om/transform-reads
;; Issue is when having two siblings or cousins with the same read-key 
;; in nested at level 2 or deeper, transform-reads will two paths
;; with the same root. Parsing such query will overwrite the first path
;; returning only the second one. 

;; Example:
;; (om/transform-reads r [:foo])
;; returns: [#:join{:parent [#:join{:child1 [:foo]}]} 
;;           #:join{:parent [#:join{:child2 [:foo]}]}]
;; Parsing the query will return :foo only for the second path:
;; #:join{:parent #:join{:child2 {:foo 1}}}

;; Repro:

(require '[om.next :as om :refer [defui]])
(require '[om.dom :as dom])

;; Is it possible to repro without a render target? Doesn't seem like it.
(require '[goog.dom :as gdom])
(def render-target (gdom/getElement "app-div"))

(defui Child1
  static om/IQuery
  (query [this] [:foo])
;;               ^^^^ important
    Object
  (render [this] 
    (dom/div nil "child1")))

(defui Child2
  static om/IQuery
  (query [this] [:foo])
;;               ^^^^ important
    Object
  (render [this] 
    (dom/div nil "child2")))

(defui Parent
  static om/IQuery
  (query [this] 
    [{:join/child1 (om/get-query Child1)}
     {:join/child2 (om/get-query Child2)}])
  Object
  (render [this] 
    (dom/div nil "parent"
      ((om/factory Child1) (:join/child1 (om/props this)))
      ((om/factory Child2) (:join/child2 (om/props this))))))

(defui Grandparent
  static om/IQuery
  (query [this] [{:join/parent (om/get-query Parent)}])
    Object
  (render [this] 
    (dom/div nil "grandparent"
      ((om/factory Parent) (:join/parent (om/props this))))))

;; Needs a read for repro.
(defn read [{:keys [parser query target state] :as env} k _]
  (if (= "join" (namespace k))
    {:value (parser env query target)}
    {:value (get @state k)}))

(def r (om/reconciler {:state (atom {:foo 1}) :parser (om/parser {:read read})}))

(om/add-root! r Grandparent render-target)
(def foo-query (om/transform-reads r [:foo]))
(prn foo-query)
;; => [#:join{:parent [#:join{:child1 [:foo]}]} #:join{:parent [#:join{:child2 [:foo]}]}]

((-> r :config :parser) (#'om/to-env r) foo-query)
;; => #:join{:parent #:join{:child2 {:foo 1}}}
;; Missing out on the child1's query.
;; Query must be merged to get both.