1 files changed, 42 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Frame-onStep-generator-resumption-01.js b/js/src/jit-test/tests/debug/Frame-onStep-generator-resumption-01.js
new file mode 100644
index 0000000000..ad61ccd9e4
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Frame-onStep-generator-resumption-01.js
@@ -0,0 +1,42 @@
+// The debugger can't force return from a generator before the initial yield.
+
+let g = newGlobal({newCompartment: true});
+g.eval(`
+  function* f() {
+    yield 1;
+  }
+`);
+
+let dbg = new Debugger(g);
+let steps = 0;
+let uncaughtErrorsReported = 0;
+dbg.onEnterFrame = frame => {
+  assertEq(frame.callee.name, "f");
+  dbg.onEnterFrame = undefined;
+  frame.onStep = () => {
+    steps++;
+
+    // This test case never resumes the generator after the initial
+    // yield. Therefore the initial yield has not happened yet. So this
+    // force-return will be an error.
+    return {return: "ponies"};
+  };
+
+  // Having an onPop hook exercises some assertions that don't happen
+  // otherwise.
+  frame.onPop = completion => {};
+};
+
+dbg.uncaughtExceptionHook = (reason) => {
+  // When onEnterFrame returns an invalid resumption value,
+  // the error is reported here.
+  assertEq(reason instanceof TypeError, true);
+  uncaughtErrorsReported++;
+  return undefined;  // Cancel the force-return. Let the debuggee continue.
+};
+
+let result = g.f();
+assertEq(result instanceof g.f, true);
+
+assertEq(steps > 0, true);
+assertEq(uncaughtErrorsReported, steps);