1 files changed, 61 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Object-forceLexicalInitializationByName.js b/js/src/jit-test/tests/debug/Object-forceLexicalInitializationByName.js
new file mode 100644
index 0000000000..7550d15ef0
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Object-forceLexicalInitializationByName.js
@@ -0,0 +1,61 @@
+load(libdir + "asserts.js");
+
+var g = newGlobal({newCompartment: true});
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+
+let errorOne, errorTwo;
+
+function evalErrorStr(global, evalString) {
+    try {
+        global.evaluate(evalString);
+        return undefined;
+    } catch (e) {
+        return e.toString();
+    }
+}
+
+
+assertEq(evalErrorStr(g, "let y = IDONTEXIST;"), "ReferenceError: IDONTEXIST is not defined");
+assertEq(evalErrorStr(g, "y = 1;"),
+         "ReferenceError: can't access lexical declaration 'y' before initialization");
+
+// Here we flip the uninitialized binding to undfined.
+assertEq(gw.forceLexicalInitializationByName("y"), true);
+assertEq(g.evaluate("y"), undefined);
+g.evaluate("y = 1;");
+assertEq(g.evaluate("y"), 1);
+
+// Ensure that bogus bindings return false, but otherwise trigger no error or
+// side effect.
+assertEq(gw.forceLexicalInitializationByName("idontexist"), false);
+assertEq(evalErrorStr(g, "idontexist"), "ReferenceError: idontexist is not defined");
+
+// Ensure that ropes (non-atoms) behave properly
+assertEq(gw.forceLexicalInitializationByName(("foo" + "bar" + "bop" + "zopple" + 2 + 3).slice(1)),
+                                             false);
+assertEq(evalErrorStr(g, "let oobarbopzopple23 = IDONTEXIST;"), "ReferenceError: IDONTEXIST is not defined");
+assertEq(gw.forceLexicalInitializationByName(("foo" + "bar" + "bop" + "zopple" + 2 + 3).slice(1)),
+                                             true);
+assertEq(g.evaluate("oobarbopzopple23"), undefined);
+
+// Ensure that only strings are accepted by forceLexicalInitializationByName
+const bad_types = [
+    2112,
+    {geddy: "lee"},
+    () => 1,
+    [],
+    Array,
+    "'1'", // non-identifier
+]
+
+for (var badType of bad_types) {
+    assertThrowsInstanceOf(() => {
+        gw.forceLexicalInitializationByName(badType);
+    }, TypeError);
+}
+
+// Finally, supplying no arguments should throw a type error
+assertThrowsInstanceOf(() => {
+    Debugger.isCompilableUnit();
+}, TypeError);