Add partial tests for import defer

features.txt

@@ -84,6 +84,10 @@ Atomics.pause
 # https://github.com/tc39/proposal-is-error
 Error.isError
 
+# Deferred import evaluation
+# https://tc39.es/proposal-defer-import-eval
+import-defer
+
 ## Standard language features
 #
 # Language features that have been included in a published version of the

test/language/import/import-defer/deferred-namespace-object/dep-defer-ns_FIXTURE.js

@@ -0,0 +1,6 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import defer * as depDeferredNamespace from "./dep_FIXTURE.js";
+
+export { depDeferredNamespace };

test/language/import/import-defer/deferred-namespace-object/dep_FIXTURE.js

@@ -0,0 +1,5 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+export const foo = 1;
+export const bar = 2;

test/language/import/import-defer/deferred-namespace-object/exotic-object-behavior.js

@@ -0,0 +1,52 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-modulenamespacecreate
+description: >
+  Deferred namespace objects have the correct MOP implementation
+info: |
+  ModuleNamespaceCreate ( _module_, _exports_, _phase_ )
+    1. Let _internalSlotsList_ be the internal slots listed in <emu-xref href="#table-internal-slots-of-module-namespace-exotic-objects"></emu-xref>.
+    1. Let _M_ be MakeBasicObject(_internalSlotsList_).
+    1. Set _M_'s essential internal methods to the definitions specified in <emu-xref href="#sec-module-namespace-exotic-objects"></emu-xref>.
+    1. ...
+
+  [[GetPrototypeOf]] ( )
+    1. Return null.
+
+  [[IsExtensible]] ( )
+    1. Return false.
+
+flags: [module]
+features: [import-defer]
+includes: [propertyHelper.js, compareArray.js]
+---*/
+
+import defer * as ns from "./dep_FIXTURE.js";
+
+assert.sameValue(typeof ns, "object", "Deferred namespaces are objects");
+
+assert(!Reflect.isExtensible(ns), "Deferred namespaces are not extensible");
+assert.sameValue(Reflect.preventExtensions(ns), true, "Deferred namespaces can made non-extensible");
+
+assert.sameValue(Reflect.getPrototypeOf(ns), null, "Deferred namespaces have a null prototype");
+assert.sameValue(Reflect.setPrototypeOf(ns, {}), false, "Deferred namespaces' prototype cannot be changed");
+assert.sameValue(Reflect.setPrototypeOf(ns, null), true, "Deferred namespaces' prototype can be 'set' to null");
+
+assert.throws(TypeError, () => Reflect.apply(ns, null, []), "Deferred namespaces are not callable");
+assert.throws(TypeError, () => Reflect.construct(ns, null, []), "Deferred namespaces are not constructable");
+
+assert.compareArray(
+  Reflect.ownKeys(ns),
+  ["bar", "foo", Symbol.toStringTag],
+  "Deferred namespaces' keys are the exports sorted alphabetically, followed by @@toStringTag"
+);
+
+verifyProperty(ns, "foo", {
+  value: 1,
+  writable: true,
+  enumerable: true,
+  configurable: false,
+});
+assert.sameValue(Reflect.getOwnPropertyDescriptor(ns, "non-existent"), undefined, "No descriptors for non-exports");

test/language/import/import-defer/deferred-namespace-object/identity.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-getmodulenamespace
+description: >
+  Deferred namespace objects are created and cached appropriately
+info: |
+  GetModuleNamespace ( _module_, _phase_ )
+    1. ...
+    1. If _phase_ is ~defer~, let _namespace_ be _module_.[[DeferredNamespace]], otherwise let _namespace_ be _module_.[[Namespace]].
+    1. If _namespace_ is ~empty~, then
+      1. ...
+      1. Set _namespace_ to ModuleNamespaceCreate(_module_, _unambiguousNames_, _phase_).
+    1. Return _namespace_.
+
+  ModuleNamespaceCreate ( _module_, _exports_, _phase_ )
+    1. ...
+    1. Let _M_ be MakeBasicObject(_internalSlotsList_).
+    1. ...
+    1. If _phase_ is ~defer~, then
+      1. Set _module_.[[DeferredNamespace]] to _M_.
+      1. ...
+    1. Else,
+      1. Set _module_.[[Namespace]] to _M_.
+      1. ...
+    1. Return _M_.
+
+flags: [module]
+features: [import-defer]
+---*/
+
+import * as nsEager from "./dep_FIXTURE.js";
+
+import defer * as nsDeferred1 from "./dep_FIXTURE.js";
+import defer * as nsDeferred2 from "./dep_FIXTURE.js";
+import { depDeferredNamespace as nsDeferred3 } from "./dep-defer-ns_FIXTURE.js";
+const nsDeferred4 = await import.defer("./dep_FIXTURE.js");
+
+assert.sameValue(nsDeferred1, nsDeferred2, "Deferred import of the same module twice gives the same object");
+assert.sameValue(nsDeferred1, nsDeferred3, "Deferred import of the same module twice from different files gives the same object");
+assert.sameValue(nsDeferred1, nsDeferred4, "Static and dynamic deferred import of the same module gives the same object");
+assert.notSameValue(nsDeferred1, nsEager, "Deferred namespaces are distinct from eager namespaces");

test/language/import/import-defer/errors/get-other-while-dep-evaluating-async/dep-1-tla_FIXTURE.js

@@ -0,0 +1,13 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import { resolveFirst, resolveThird, second } from "./promises_FIXTURE.js";
+import "./dep-1.1_FIXTURE.js"
+
+await Promise.resolve();
+
+resolveFirst();
+
+await second;
+
+resolveThird();

test/language/import/import-defer/errors/get-other-while-dep-evaluating-async/dep-1.1.1_FIXTURE.js

@@ -0,0 +1,6 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import defer * as ns from "./dep-1-tla_FIXTURE.js";
+
+export let foo = 1;

test/language/import/import-defer/errors/get-other-while-dep-evaluating-async/dep-1.1_FIXTURE.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import { first, third, rejectDone, resolveDone, resolveSecond } from "./promises_FIXTURE.js";
+import defer * as ns from "./dep-1.1.1_FIXTURE.js";
+
+// dep-1 is now in the ~evaluating~ state
+try {
+  ns.foo;
+} catch (error) {
+  globalThis["error on ns.foo while evaluating"] = error;
+}
+
+first.then(() => {
+  // dep-1 is now in the ~evaluating-async~ state
+  try {
+    ns.foo;
+  } catch (error) {
+    globalThis["error on ns.foo while evaluating-async"] = error;
+  }
+  resolveSecond();
+}).then(() => {
+  return third.then(() => {
+    // dep-1 is now in the ~evaluated~ state
+    let foo = ns.foo;
+    globalThis["value of ns.foo when evaluated"] = foo;
+  })
+}).then(resolveDone, rejectDone);

test/language/import/import-defer/errors/get-other-while-dep-evaluating-async/main.js

@@ -0,0 +1,47 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-module-namespace-exotic-objects-get-p-receiver-EnsureDeferredNamespaceEvaluation
+description: >
+  Modules cannot try to trigger evaluation of modules that have dependencies in their ~evaluating-async~ phase
+info: |
+  10.4.6.8 [[Get]] ( _P_, _Receiver_ )
+    1. ...
+    1. If _O_.[[Deferred]] is **true**, perform ? EnsureDeferredNamespaceEvaluation(_O_).
+    1. ...
+
+  EnsureDeferredNamespaceEvaluation ( _O_ )
+    1. Assert: _O_.[[Deferred]] is *false*.
+    1. Let _m_ be _O_.[[Module]].
+    1. If _m_ is a Cyclic Module Record, _m_.[[Status]] is not ~evaluated~, and ReadyForSyncExecution(_m_) is *false*, throw a *TypeError* exception.
+    1. ...
+
+  ReadyForSyncExecution( _module_, _seen_ )
+    1. If _seen_ is not provided, let _seen_ be a new empty List.
+    1. If _seen_ contains _module_, return *true*.
+    1. Append _module_ to _seen_.
+    1. If _module_.[[Status]] is ~evaluated~, return *true*.
+    1. If _module_.[[Status]] is ~evaluating~ or ~evaluating-async~, return *false*.
+    1. Assert: _module_.[[Status]] is ~linked~.
+    1. If _module_.[[HasTLA]] is *true*, return *false*.
+    1. For each ModuleRequest Record _required_ of _module_.[[RequestedModules]], do
+      1. Let _requiredModule_ be GetImportedModule(_module_, _required_.[[Specifier]]).
+      1. If ReadyForSyncExecution(_requiredModule_, _seen_) is *false*, then
+        1. Return *false*.
+    1. Return *true*.
+
+flags: [module, async]
+features: [import-defer, top-level-await]
+includes: [asyncHelpers.js]
+---*/
+
+import { done } from "./promises_FIXTURE.js";
+import "./dep-1-tla_FIXTURE.js";
+
+asyncTest(async () => {
+  await done;
+  assert(globalThis["error on ns.foo while evaluating"] instanceof TypeError, "ns.foo while evaluating throws a TypeError");
+  assert(globalThis["error on ns.foo while evaluating-async"] instanceof TypeError, "ns.foo while evaluating-async throws a TypeError");
+  assert.sameValue(globalThis["value of ns.foo when evaluated"], 1);
+});

test/language/import/import-defer/errors/get-other-while-dep-evaluating-async/promises_FIXTURE.js

@@ -0,0 +1,14 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+export let resolveDone, rejectDone;
+export const done = new Promise((r, j) => (resolveDone = r, rejectDone = j));
+
+export let resolveFirst, rejectFirst;
+export const first = new Promise((r, j) => (resolveFirst = r, rejectFirst = j));
+
+export let resolveSecond, rejectSecond;
+export const second = new Promise((r, j) => (resolveSecond = r, rejectSecond = j));
+
+export let resolveThird, rejectThird;
+export const third = new Promise((r, j) => (resolveThird = r, rejectThird = j));

test/language/import/import-defer/errors/get-other-while-dep-evaluating/dep-1_FIXTURE.js

@@ -0,0 +1,14 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import defer * as dep2 from "./dep-2_FIXTURE.js";
+
+globalThis.dep3evaluated = false;
+
+try {
+  dep2.foo;
+} catch (error) {
+  globalThis["evaluating dep2.foo error"] = error;
+}
+
+globalThis["evaluating dep2.foo evaluates dep3"] = globalThis.dep3evaluated;

test/language/import/import-defer/errors/get-other-while-dep-evaluating/dep-2_FIXTURE.js

@@ -0,0 +1,5 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import "./dep-3_FIXTURE.js";
+import "./main.js";

test/language/import/import-defer/errors/get-other-while-dep-evaluating/dep-3_FIXTURE.js

@@ -0,0 +1,4 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+globalThis.dep3evaluated = true;

test/language/import/import-defer/errors/get-other-while-dep-evaluating/main.js

@@ -0,0 +1,42 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-module-namespace-exotic-objects-get-p-receiver-EnsureDeferredNamespaceEvaluation
+description: >
+  Modules cannot try to trigger their own evaluation
+info: |
+  10.4.6.8 [[Get]] ( _P_, _Receiver_ )
+    1. ...
+    1. If _O_.[[Deferred]] is **true**, perform ? EnsureDeferredNamespaceEvaluation(_O_).
+    1. ...
+
+  EnsureDeferredNamespaceEvaluation ( _O_ )
+    1. Assert: _O_.[[Deferred]] is *false*.
+    1. Let _m_ be _O_.[[Module]].
+    1. If _m_ is a Cyclic Module Record, _m_.[[Status]] is not ~evaluated~, and ReadyForSyncExecution(_m_) is *false*, throw a *TypeError* exception.
+    1. ...
+
+  ReadyForSyncExecution( _module_, _seen_ )
+    1. If _seen_ is not provided, let _seen_ be a new empty List.
+    1. If _seen_ contains _module_, return *true*.
+    1. Append _module_ to _seen_.
+    1. If _module_.[[Status]] is ~evaluated~, return *true*.
+    1. If _module_.[[Status]] is ~evaluating~ or ~evaluating-async~, return *false*.
+    1. Assert: _module_.[[Status]] is ~linked~.
+    1. If _module_.[[HasTLA]] is *true*, return *false*.
+    1. For each ModuleRequest Record _required_ of _module_.[[RequestedModules]], do
+      1. Let _requiredModule_ be GetImportedModule(_module_, _required_.[[Specifier]]).
+      1. If ReadyForSyncExecution(_requiredModule_, _seen_) is *false*, then
+        1. Return *false*.
+    1. Return *true*.
+
+flags: [module]
+features: [import-defer]
+---*/
+
+import "./dep-1_FIXTURE.js";
+
+assert(globalThis["evaluating dep2.foo error"] instanceof TypeError, "evaluating dep2.foo throws a TypeError");
+assert(!globalThis["evaluating dep2.foo evaluates dep3"], "evaluating dep2.foo does not evaluate dep3");
+assert(!globalThis.dep3evaluated, "dep3 is not evaluated at all");

test/language/import/import-defer/errors/get-other-while-evaluating-async/dep-1-tla_FIXTURE.js

@@ -0,0 +1,15 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import { resolveFirst, resolveThird, second } from "./promises_FIXTURE.js";
+import "./dep-1.1_FIXTURE.js"
+
+await Promise.resolve();
+
+resolveFirst();
+
+await second;
+
+resolveThird();
+
+export let foo = 1;

test/language/import/import-defer/errors/get-other-while-evaluating-async/dep-1.1_FIXTURE.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+import { first, third, resolveSecond, rejectDone, resolveDone } from "./promises_FIXTURE.js";
+import defer * as ns from "./dep-1-tla_FIXTURE.js";
+
+// ns is now in the ~evaluating~ state
+try {
+  ns.foo;
+} catch (error) {
+  globalThis["error on ns.foo while evaluating"] = error;
+}
+
+first.then(() => {
+  // ns is now in the ~evaluating-async~ state
+  try {
+    ns.foo;
+  } catch (error) {
+    globalThis["error on ns.foo while evaluating-async"] = error;
+  }
+  resolveSecond();
+}).then(() => {
+  return third.then(() => {
+    // ns is now in the ~evaluated~ state
+    let foo = ns.foo;
+    globalThis["value of ns.foo when evaluated"] = foo;
+  })
+}).then(resolveDone, rejectDone);

test/language/import/import-defer/errors/get-other-while-evaluating-async/main.js

@@ -0,0 +1,47 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-module-namespace-exotic-objects-get-p-receiver-EnsureDeferredNamespaceEvaluation
+description: >
+  Modules cannot try to trigger evaluation of modules that are in their ~evaluating-async~ phase
+info: |
+  10.4.6.8 [[Get]] ( _P_, _Receiver_ )
+    1. ...
+    1. If _O_.[[Deferred]] is **true**, perform ? EnsureDeferredNamespaceEvaluation(_O_).
+    1. ...
+
+  EnsureDeferredNamespaceEvaluation ( _O_ )
+    1. Assert: _O_.[[Deferred]] is *false*.
+    1. Let _m_ be _O_.[[Module]].
+    1. If _m_ is a Cyclic Module Record, _m_.[[Status]] is not ~evaluated~, and ReadyForSyncExecution(_m_) is *false*, throw a *TypeError* exception.
+    1. ...
+
+  ReadyForSyncExecution( _module_, _seen_ )
+    1. If _seen_ is not provided, let _seen_ be a new empty List.
+    1. If _seen_ contains _module_, return *true*.
+    1. Append _module_ to _seen_.
+    1. If _module_.[[Status]] is ~evaluated~, return *true*.
+    1. If _module_.[[Status]] is ~evaluating~ or ~evaluating-async~, return *false*.
+    1. Assert: _module_.[[Status]] is ~linked~.
+    1. If _module_.[[HasTLA]] is *true*, return *false*.
+    1. For each ModuleRequest Record _required_ of _module_.[[RequestedModules]], do
+      1. Let _requiredModule_ be GetImportedModule(_module_, _required_.[[Specifier]]).
+      1. If ReadyForSyncExecution(_requiredModule_, _seen_) is *false*, then
+        1. Return *false*.
+    1. Return *true*.
+
+flags: [module, async]
+features: [import-defer, top-level-await]
+includes: [asyncHelpers.js]
+---*/
+
+import { done } from "./promises_FIXTURE.js";
+import "./dep-1-tla_FIXTURE.js";
+
+asyncTest(async () => {
+  await done;
+  assert(globalThis["error on ns.foo while evaluating"] instanceof TypeError, "ns.foo while evaluating throws a TypeError");
+  assert(globalThis["error on ns.foo while evaluating-async"] instanceof TypeError, "ns.foo while evaluating-async throws a TypeError");
+  assert.sameValue(globalThis["value of ns.foo when evaluated"], 1);
+});