1 files changed, 54 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Environment-module-tla-env-after-pop.js b/js/src/jit-test/tests/debug/Environment-module-tla-env-after-pop.js
new file mode 100644
index 0000000000..4d4d408d9e
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Environment-module-tla-env-after-pop.js
@@ -0,0 +1,54 @@
+// Accessing the variables in the snapshot after popping the module
+// should work until the module's top-level script's evaluation finishes.
+
+var g = newGlobal({newCompartment: true});
+g.eval(`
+var accessVarInSnapshot = null;
+`);
+g.eval(`
+var resolve;
+var p = new Promise(r => resolve = r);
+`);
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+dbg.onDebuggerStatement = function (frame) {
+  assertEq(frame.environment.getVariable("x"), 10);
+  frame.eval("accessVarInSnapshot = function() { return ++x }");
+  assertEq(gw.executeInGlobal("accessVarInSnapshot()").return, 11);
+};
+const m = g.parseModule(`
+  let x = 10;
+  await 20;
+  debugger;
+  await p;
+`);
+moduleLink(m);
+
+// Run until `await p`.
+moduleEvaluate(m);
+
+drainJobQueue();
+
+assertEq(g.accessVarInSnapshot !== null, true);
+
+// At this point, the module's top-level script's evaluation isn't yet finished,
+// and the module's ScriptSlot is still alive.
+// Accessing the snapshot should work.
+assertEq(g.accessVarInSnapshot(), 12);
+
+// Continue the module's top-level script's evaluation.
+g.eval(`
+resolve();
+`);
+
+drainJobQueue();
+
+// At this point, the module's ScriptSlot is cleared and accessing the
+// snapshot doesn't work.
+try {
+  g.accessVarInSnapshot();
+  // the above should throw.
+  assertEq(true, false);
+} catch (e) {
+  assertEq(e+"", "ReferenceError: x is not defined");
+}