fix(ext/web): propagate aborted state to dependent signals before fir…

…ing events

Ref whatwg/dom#1295

Fixes denoland#25118

ext/web/03_abort_signal.js

@@ -69,6 +69,7 @@ class WeakRefSet {
 }
 
 const add = Symbol("[[add]]");
+const setAbortReason = Symbol("[[setAbortReason]]");
 const signalAbort = Symbol("[[signalAbort]]");
 const remove = Symbol("[[remove]]");
 const abortReason = Symbol("[[abortReason]]");
@@ -148,7 +149,22 @@ class AbortSignal extends EventTarget {
     if (this.aborted) {
       return;
     }
-    this[abortReason] = reason;
+
+    this[setAbortReason](reason);
+
+    const dependentSignalsToAbort = [];
+    if (this[dependentSignals] !== null) {
+      const dependentSignalArray = this[dependentSignals].toArray();
+      for (let i = 0; i < dependentSignalArray.length; ++i) {
+        const dependentSignal = dependentSignalArray[i];
+
+        if (!dependentSignal.aborted) {
+          dependentSignal[setAbortReason](reason);
+          dependentSignalsToAbort.push(dependentSignal);
+        }
+      }
+    }
+
     const algos = this[abortAlgos];
     this[abortAlgos] = null;
 
@@ -163,15 +179,19 @@ class AbortSignal extends EventTarget {
       }
     }
 
-    if (this[dependentSignals] !== null) {
-      const dependentSignalArray = this[dependentSignals].toArray();
-      for (let i = 0; i < dependentSignalArray.length; ++i) {
-        const dependentSignal = dependentSignalArray[i];
-        dependentSignal[signalAbort](reason);
-      }
+    for (let i = 0; i < dependentSignalsToAbort.length; ++i) {
+      const dependentSignal = dependentSignalsToAbort[i];
+      dependentSignal[signalAbort](reason);
     }
   }
 
+  [setAbortReason](reason) {
+    if (this.aborted) {
+      return;
+    }
+    this[abortReason] = reason;
+  }
+
   [remove](algorithm) {
     this[abortAlgos] && SetPrototypeDelete(this[abortAlgos], algorithm);
   }

tests/unit/abort_controller_test.ts

@@ -62,3 +62,22 @@ Deno.test(function abortReason() {
   assertEquals(signal.aborted, true);
   assertEquals(signal.reason, "hey!");
 });
+
+Deno.test(function dependentSignalsAborted() {
+  const controller = new AbortController();
+  const signal1 = AbortSignal.any([controller.signal]);
+  const signal2 = AbortSignal.any([signal1]);
+  let eventFired = false;
+
+  controller.signal.addEventListener("abort", () => {
+    const signal3 = AbortSignal.any([signal2]);
+    assert(controller.signal.aborted);
+    assert(signal1.aborted);
+    assert(signal2.aborted);
+    assert(signal3.aborted);
+    eventFired = true;
+  });
+
+  controller.abort();
+  assert(eventFired, "event fired");
+});