weird.clj

(defn waitForFuture [timeout & refs] (doseq [r refs] (deref r timeout nil)))

(def phrase (ref "hello"))

(waitForFuture 1 
 (future (dosync (println "will rename phrase") (Thread/sleep 1000) (ref-set phrase "world")))
 (future (dosync (println @phrase) (Thread/sleep 2000) (println @phrase))))

;; What I get here
;; > will rename phrase -- first future kicks in 
;; > hello              -- second future kicks in
;; > nil                          
;; > world              -- aaand second future redone it's stuff cause ref was changed, 
;; > world

;; Now, when I eval the same thing, but only after resetting thing with dosync

(dosync (ref-set phrase "hello"))

(waitForFuture 1 
 (future (dosync (println "will rename phrase") (Thread/sleep 1000) (ref-set phrase "world")))
 (future (dosync (println @phrase) (Thread/sleep 2000) (println @phrase))))

;; What I get is next:

;; > will rename phrase -- first future kicks in
;; > hello              -- second future kicks in
;; > nil                         
;; > hello              -- wowowow, wait a second, isn't ref phrase was renamed in first future?
;;                      -- shouldn't STM do it STMish things and retry here?