Hi,
I can reproduce it with 1.2 and 1.3.0-master-20100911.130147-5. And I
think I know, what the problem is: You must not recur out of a
binding. The binding implicitely contains a try with cleanup code in
the finally clause. It seems that recur bypasses the finally and
executes again the binding. This pushes another frame of the bindings
onto the stack, but the old frame is not popped. When the exception is
thrown, the finally part gets executed and one frame is popped, but
the additional frames remain. The stack of bindings is now out of
sync. Hence your result. Throwing the exception in the first iteration
will leave the bindings stack intact.
user=> (binding [x [1 2 3]] (loop [c 0] (binding [y [4 5 6]] (throw
(Exception. "BOOOM")))))
Exception BOOOM user/eval13 (NO_SOURCE_FILE:9)
user=> x
IllegalStateException Var user/x is unbound. clojure.lang.Var.deref
(Var.java:142)
user=> y
IllegalStateException Var user/y is unbound. clojure.lang.Var.deref
(Var.java:142)
Please find the following code, which works as expected:
(defn test-fixed-nested-binding
[]
(binding [x [0 1 2 3 4 5 6]]
(try
(binding [y [7 8 9]]
(loop [c 0]
(change-value-of-thread-local-var)
(throw-random-exception c)
(recur (inc c))))
(catch Exception e (println (str x "\n" (.getMessage e)))))))
Since recur is local, I think "don't do it" is a valid short- to mid-
term fix.
Sincerely
Meikel
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
