timers: set _destroyed even if there are no destroy-hooks

Required for other potential changes.

This should make it so we can always just check _destroyed to
check if a timer has been ended.

PR-URL: #29595
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/timers.js

@@ -544,8 +544,8 @@ function getTimerCallbacks(runNextTicks) {
 
           if (destroyHooksExist() && !timer._destroyed) {
             emitDestroy(timer[async_id_symbol]);
-            timer._destroyed = true;
           }
+          timer._destroyed = true;
         }
       }
 

lib/timers.js

@@ -65,8 +65,8 @@ function unenroll(item) {
       item[async_id_symbol] !== undefined &&
       !item._destroyed) {
     emitDestroy(item[async_id_symbol]);
-    item._destroyed = true;
   }
+  item._destroyed = true;
 
   L.remove(item);
 

test/parallel/test-timers-destroyed.js

@@ -0,0 +1,27 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+// We don't really care about the calling results here.
+// So, this makes the test less fragile.
+const noop = () => {};
+
+const t1 = setTimeout(common.mustNotCall(), 1);
+const t2 = setTimeout(common.mustCall(), 1);
+const i1 = setInterval(common.mustNotCall(), 1);
+const i2 = setInterval(noop, 1);
+i2.unref();
+
+// Keep process alive for i2 to call once due to timer ordering.
+setTimeout(common.mustCall(), 1);
+
+clearTimeout(t1);
+clearInterval(i1);
+
+process.on('exit', () => {
+  assert.strictEqual(t1._destroyed, true);
+  assert.strictEqual(t2._destroyed, true);
+  assert.strictEqual(i1._destroyed, true);
+  assert.strictEqual(i2._destroyed, false);
+});