Turning on *resource-debug-double-free* makes every stack/track call throw ClassCastException

[willcohen]

One liner repro:
clj -Sdeps '{:deps {techascent/tech.resource {:mvn/version "5.09"}}}' -M -e "(require (quote [tech.v3.resource.stack :as s])) (alter-var-root (var s/*resource-debug-double-free*) (constantly true)) (s/track (Object.) (fn []))"

Output:

true
Execution error (ClassCastException) at tech.v3.resource.stack/track (stack.clj:46).
class java.util.ArrayList cannot be cast to class java.util.concurrent.Future (java.util.ArrayList and java.util.concurrent.Future are in module java.base of loader 'bootstrap')

Potential fix:

--- a/src/tech/v3/resource/stack.clj
+++ b/src/tech/v3/resource/stack.clj
@@ -43,7 +43,7 @@
   itself.  Else the dispose function is tracked."
   ([item dispose-fn]
    (when (and *resource-debug-double-free*
-              (some #(identical? item %) @*resource-context*))
+              (some #(identical? item (first %)) *resource-context*))
      (throw (ex-info "Duplicate track detected; this will result in a double free"
                      {:item item})))
    (when-not *bound-resource-context?*

When change noted above is applied
clj -Sdeps '{:deps {techascent/tech.resource {:local/root "/path/to/local/tech.resource"}}}' -M -e "(require (quote [tech.v3.resource.stack :as s])) (alter-var-root (var s/*resource-debug-double-free*) (constantly true)) (let [o (Object.)] (s/track o (fn [])) (println \"first track OK\") (s/track o (fn [])))"

Output:

true
Apr 17, 2026 10:10:08 PM clojure.tools.logging$eval449$fn__452 invoke
WARNING: Stack resource tracking used but no resource context bound.
This is probably a memory leak.
first track OK
Execution error (ExceptionInfo) at tech.v3.resource.stack/track (stack.clj:47).
Duplicate track detected; this will result in a double free

Is this flag meant to still be supported?

[willcohen]

I included that fix with a regression test in #5!