Isolate sessions

[SevereOverfl0w]

#!/bin/sh

"exec" "clojure" "-Sdeps" '{:deps {nrepl/nrepl {:mvn/version "1.3.1"}}}' "$0" "$@"

(require '[nrepl.core :as nrepl])

(with-open [conn (nrepl/connect :port 1339)]
  (let [client (nrepl/client conn 1000)
        a (nrepl/new-session client)            ; two sessions, ONE connection
        b (nrepl/new-session client)
        ev (fn [s code] (->> (nrepl/message client {:op "eval" :session s :code code})
                             (keep :value) vec))]
    (println "[A] (+ 40 2) =>" (ev a "(+ 40 2)"))
    (println "[A] *1       =>" (ev a "*1"))
    (println "[B] *1       =>" (ev b "*1") "  <- same conn, diff session")
    (println "[B] (+ 1 1)  =>" (ev b "(+ 1 1)"))
    (println "[A] *1       =>" (ev a "*1") "  <- B clobbered A")))

Right now, *1 gets shared between sessions. nrepl spec says that session ThreadLocals should be isolated from one another, e.g. *1. This matters if tooling is performing background eval on your behalf and the user unexpectedly receives different values for *1, *e, etc.

[borkdude]

Extra comment from Slack: this is only relevant to some ops, e.g. eval.