1 files changed, 40 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/stream/bug-1387503-2.js b/js/src/jit-test/tests/stream/bug-1387503-2.js
new file mode 100644
index 0000000000..d6885f325a
--- /dev/null
+++ b/js/src/jit-test/tests/stream/bug-1387503-2.js
@@ -0,0 +1,40 @@
+// |jit-test| skip-if: !this.hasOwnProperty("ReadableStream")
+// Test uncatchable error when a stream's queuing strategy's size() method is called.
+
+// Make `debugger;` raise an uncatchable exception.
+let g = newGlobal({newCompartment: true});
+g.parent = this;
+g.hit = false;
+g.eval(`
+    var dbg = new Debugger(parent);
+    dbg.onDebuggerStatement = (_frame, exc) => (hit = true, null);
+`);
+
+let fnFinished = false;
+async function fn() {
+    // Await once to postpone the uncatchable error until we're running inside
+    // a reaction job. We don't want the rest of the test to be terminated.
+    // (`drainJobQueue` catches uncatchable errors!)
+    await 1; 
+
+    try {
+        // Create a stream with a strategy whose .size() method raises an
+        // uncatchable exception, and have it call that method.
+        new ReadableStream({
+            start(controller) {
+                controller.enqueue("FIRST POST");  // this calls .size()
+            }
+        }, {
+            size() {
+                debugger;
+            }
+        });
+    } finally {
+        fnFinished = true;
+    }
+}
+
+fn();
+drainJobQueue();
+assertEq(g.hit, true);
+assertEq(fnFinished, false);