chaperone-evt: don't drop other chaperones

pkgs/racket-pkgs/racket-test/tests/racket/chaperone.rktl

@@ -1245,6 +1245,20 @@
   (err/rt-test (sync (chaperone-evt evt redirect-3)))
   (err/rt-test (sync (chaperone-evt evt redirect-4))))
 
+;; check that evt-chaperone handling doesn't intefere with other chaperones:
+(let ()
+  (struct e (orig)
+    #:property prop:input-port 0)
+  (define an-e (e (open-input-string "s")))
+  (define checked? #f)
+  (test #t input-port? an-e)
+  (sync (chaperone-struct an-e
+                          e-orig
+                          (lambda (self v)
+                            (set! checked? #t)
+                            v)))
+  (test #t values checked?))
+
 ;; ----------------------------------------
 ;; channel chaperones
 

racket/src/racket/src/struct.c

@@ -3615,19 +3615,29 @@ static Scheme_Object *chaperone_evt(int argc, Scheme_Object *argv[])
   return scheme_do_chaperone_evt("chaperone-evt", 0, argc, argv);
 }
 
-static int chaperone_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
+static int chaperone_evt_is_ready(Scheme_Object *obj, Scheme_Schedule_Info *sinfo)
 {
+  Scheme_Object *o = obj;
   Scheme_Chaperone *px;
+  int redirected = 0;
 
   while (SCHEME_CHAPERONEP(o)) {
     px = (Scheme_Chaperone *)o;
     if (SAME_TYPE(SCHEME_TYPE(px->redirects), scheme_nack_guard_evt_type)) {
       o = px->redirects;
+      redirected = 1;
       break;
     }
     o = px->prev;
   }
 
+  if (!redirected && SCHEME_STRUCTP(o)) {
+    /* No chaperone was an `evt` chaperone. Don't discard
+       other chaperones, because they may be relevant for
+       structure properties. */
+    return evt_struct_is_ready(obj, sinfo);
+  }
+
   scheme_set_sync_target(sinfo, o, NULL, NULL, 0, 1, NULL);
   return 0;
 }