fix(capabilities): unref the wasm transport sleep timer so the host can exit

The wasm exporter races a sleep(timeout) against each HTTP request as a timeout
guard (and reuses it for retry backoff). On a fast success the timer is
abandoned but, being reffed, kept the Node process alive for up to the request
timeout (5 minutes) after the last flush. unref the timer: an in-flight request
refs the event loop on its own, so an abandoned/standalone timeout timer must
not block process exit.

This also fixes the Node 18 CI test jobs: scripts/test.sh now probes for
--test-force-exit (Node >= 20.14/22) and runs without it on Node 18, which
rejects the flag as unknown. With the unref above, node:test exits cleanly on
Node 18 regardless.

Author: bengl

crates/capabilities/src/http_transport.js

@@ -9,7 +9,14 @@ function isDetachedBufferError (err) {
 }
 
 module.exports.sleep = function (ms) {
-  return new Promise(resolve => setTimeout(resolve, ms))
+  return new Promise((resolve) => {
+    const timer = setTimeout(resolve, ms)
+    // The exporter races this sleep against each request as a timeout guard (and
+    // reuses it for retry backoff). An in-flight request refs the event loop on
+    // its own, so an abandoned timeout timer (e.g. the 5-minute request-timeout
+    // guard after a fast success) must not keep the host process alive.
+    timer.unref?.()
+  })
 }
 
 module.exports.setStorage = function (new_storage) {

scripts/test.sh

@@ -14,8 +14,17 @@ run_test() {
   # exporter's runtime machinery after a flush). For the long-lived real
   # consumer that is expected; for the test runner we force a clean exit once
   # all tests have finished. Only applies to files that use node:test.
+  #
+  # `--test-force-exit` exists on Node >= 20.14/22 but Node 18 rejects it as an
+  # unknown option. The wasm transport unref's its timeout/backoff timers so the
+  # process still exits cleanly without the flag; probe for support and degrade
+  # gracefully on Node 18.
   if grep -q "node:test" "$1"; then
-    node --test-force-exit "$1"
+    if node --test-force-exit --eval '' >/dev/null 2>&1; then
+      node --test-force-exit "$1"
+    else
+      node "$1"
+    fi
   else
     node "$1"
   fi