[v18.x backport] esm: use import attributes instead of import assertions

.eslintrc.js

@@ -44,10 +44,7 @@ module.exports = {
   parserOptions: {
     babelOptions: {
       plugins: [
-        [
-          Module._findPath('@babel/plugin-syntax-import-attributes'),
-          { deprecatedAssertSyntax: true },
-        ],
+        Module._findPath('@babel/plugin-syntax-import-attributes'),
       ],
     },
     requireConfigFile: false,

deps/v8/include/v8-script.h

@@ -128,10 +128,9 @@ class V8_EXPORT ModuleRequest : public Data {
    *
    * All assertions present in the module request will be supplied in this
    * list, regardless of whether they are supported by the host. Per
-   * https://tc39.es/proposal-import-assertions/#sec-hostgetsupportedimportassertions,
-   * hosts are expected to ignore assertions that they do not support (as
-   * opposed to, for example, triggering an error if an unsupported assertion is
-   * present).
+   * https://tc39.es/proposal-import-attributes/#sec-hostgetsupportedimportattributes,
+   * hosts are expected to throw for assertions that they do not support (as
+   * opposed to, for example, ignoring them).
    */
   Local<FixedArray> GetImportAssertions() const;
 

deps/v8/src/execution/isolate.cc

@@ -4726,7 +4726,7 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
 
   // The parser shouldn't have allowed the second argument to import() if
   // the flag wasn't enabled.
-  DCHECK(FLAG_harmony_import_assertions);
+  DCHECK(FLAG_harmony_import_assertions || FLAG_harmony_import_attributes);
 
   if (!import_assertions_argument->IsJSReceiver()) {
     this->Throw(
@@ -4736,18 +4736,35 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
 
   Handle<JSReceiver> import_assertions_argument_receiver =
       Handle<JSReceiver>::cast(import_assertions_argument);
-  Handle<Name> key = factory()->assert_string();
 
   Handle<Object> import_assertions_object;
-  if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver, key)
-           .ToHandle(&import_assertions_object)) {
-    // This can happen if the property has a getter function that throws
-    // an error.
-    return MaybeHandle<FixedArray>();
+
+  if (FLAG_harmony_import_attributes) {
+    Handle<Name> with_key = factory()->with_string();
+    if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver,
+                                 with_key)
+             .ToHandle(&import_assertions_object)) {
+      // This can happen if the property has a getter function that throws
+      // an error.
+      return MaybeHandle<FixedArray>();
+    }
   }
 
-  // If there is no 'assert' option in the options bag, it's not an error. Just
-  // do the import() as if no assertions were provided.
+  if (FLAG_harmony_import_assertions &&
+      (!FLAG_harmony_import_attributes ||
+       import_assertions_object->IsUndefined())) {
+    Handle<Name> assert_key = factory()->assert_string();
+    if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver,
+                                 assert_key)
+             .ToHandle(&import_assertions_object)) {
+      // This can happen if the property has a getter function that throws
+      // an error.
+      return MaybeHandle<FixedArray>();
+    }
+  }
+
+  // If there is no 'with' or 'assert' option in the options bag, it's not an
+  // error. Just do the import() as if no assertions were provided.
   if (import_assertions_object->IsUndefined()) return import_assertions_array;
 
   if (!import_assertions_object->IsJSReceiver()) {
@@ -4769,6 +4786,8 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
     return MaybeHandle<FixedArray>();
   }
 
+  bool has_non_string_attribute = false;
+
   // The assertions will be passed to the host in the form: [key1,
   // value1, key2, value2, ...].
   constexpr size_t kAssertionEntrySizeForDynamicImport = 2;
@@ -4786,9 +4805,7 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
     }
 
     if (!assertion_value->IsString()) {
-      this->Throw(*factory()->NewTypeError(
-          MessageTemplate::kNonStringImportAssertionValue));
-      return MaybeHandle<FixedArray>();
+      has_non_string_attribute = true;
     }
 
     import_assertions_array->set((i * kAssertionEntrySizeForDynamicImport),
@@ -4797,6 +4814,12 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
                                  *assertion_value);
   }
 
+  if (has_non_string_attribute) {
+    this->Throw(*factory()->NewTypeError(
+        MessageTemplate::kNonStringImportAssertionValue));
+    return MaybeHandle<FixedArray>();
+  }
+
   return import_assertions_array;
 }
 

deps/v8/src/flags/flag-definitions.h

@@ -300,6 +300,7 @@ DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
 
 // Features that are still work in progress (behind individual flags).
 #define HARMONY_INPROGRESS_BASE(V)                                             \
+  V(harmony_import_attributes, "harmony import attributes")                    \
   V(harmony_weak_refs_with_cleanup_some,                                       \
     "harmony weak references with FinalizationRegistry.prototype.cleanupSome") \
   V(harmony_import_assertions, "harmony import assertions")                    \

deps/v8/src/init/bootstrapper.cc

@@ -4482,6 +4482,7 @@ void Genesis::InitializeConsole(Handle<JSObject> extras_binding) {
   void Genesis::InitializeGlobal_##id() {}
 
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_import_assertions)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_import_attributes)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_private_brand_checks)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_class_static_blocks)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_error_cause)

deps/v8/src/init/heap-symbols.h

@@ -432,6 +432,7 @@
   V(_, week_string, "week")                                           \
   V(_, weeks_string, "weeks")                                         \
   V(_, weekOfYear_string, "weekOfYear")                               \
+  V(_, with_string, "with")                                           \
   V(_, word_string, "word")                                           \
   V(_, writable_string, "writable")                                   \
   V(_, yearMonthFromFields_string, "yearMonthFromFields")             \

deps/v8/src/parsing/parser-base.h

@@ -3725,7 +3725,9 @@ ParserBase<Impl>::ParseImportExpressions() {
   AcceptINScope scope(this, true);
   ExpressionT specifier = ParseAssignmentExpressionCoverGrammar();
 
-  if (FLAG_harmony_import_assertions && Check(Token::COMMA)) {
+  if ((FLAG_harmony_import_assertions ||
+       FLAG_harmony_import_attributes) &&
+      Check(Token::COMMA)) {
     if (Check(Token::RPAREN)) {
       // A trailing comma allowed after the specifier.
       return factory()->NewImportCallExpression(specifier, pos);

deps/v8/src/parsing/parser.cc

@@ -1344,39 +1344,42 @@ ZonePtrList<const Parser::NamedImport>* Parser::ParseNamedImports(int pos) {
 }
 
 ImportAssertions* Parser::ParseImportAssertClause() {
-  // AssertClause :
-  //    assert '{' '}'
-  //    assert '{' AssertEntries '}'
+  // WithClause :
+  //    with '{' '}'
+  //    with '{' WithEntries ','? '}'
 
-  // AssertEntries :
-  //    IdentifierName: AssertionKey
-  //    IdentifierName: AssertionKey , AssertEntries
+  // WithEntries :
+  //    LiteralPropertyName
+  //    LiteralPropertyName ':' StringLiteral , WithEntries
 
-  // AssertionKey :
-  //     IdentifierName
-  //     StringLiteral
+  // (DEPRECATED)
+  // AssertClause :
+  //    assert '{' '}'
+  //    assert '{' WithEntries ','? '}'
 
   auto import_assertions = zone()->New<ImportAssertions>(zone());
 
-  if (!FLAG_harmony_import_assertions) {
-    return import_assertions;
-  }
+  if (FLAG_harmony_import_attributes && Check(Token::WITH)) {
+    // 'with' keyword consumed
+  } else if (FLAG_harmony_import_assertions &&
+             !scanner()->HasLineTerminatorBeforeNext() &&
+             CheckContextualKeyword(ast_value_factory()->assert_string())) {
+    // The 'assert' contextual keyword is deprecated in favor of 'with', and we
+    // need to investigate feasibility of unshipping.
+    //
+    // TODO(v8:13856): Remove once decision is made to unship 'assert' or keep.
 
-  // Assert clause is optional, and cannot be preceded by a LineTerminator.
-  if (scanner()->HasLineTerminatorBeforeNext() ||
-      !CheckContextualKeyword(ast_value_factory()->assert_string())) {
+    // NOTE(Node.js): Commented out to avoid backporting this use counter to Node.js 18
+    // ++use_counts_[v8::Isolate::kImportAssertionDeprecatedSyntax];
+  } else {
     return import_assertions;
   }
 
   Expect(Token::LBRACE);
 
   while (peek() != Token::RBRACE) {
-    const AstRawString* attribute_key = nullptr;
-    if (Check(Token::STRING)) {
-      attribute_key = GetSymbol();
-    } else {
-      attribute_key = ParsePropertyName();
-    }
+    const AstRawString* attribute_key =
+        Check(Token::STRING) ? GetSymbol() : ParsePropertyName();
 
     Scanner::Location location = scanner()->location();
 

deps/v8/test/mjsunit/harmony/modules-import-attributes-1.mjs

@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import { life } from 'modules-skip-1.mjs' with { };
+
+assertEquals(42, life());

deps/v8/test/mjsunit/harmony/modules-import-attributes-2.mjs

@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import json from 'modules-skip-1.json' with { type: 'json' };
+
+assertEquals(42, json.life);

deps/v8/test/mjsunit/harmony/modules-import-attributes-3.mjs

@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import {life} from 'modules-skip-imports-json-1.mjs';
+
+assertEquals(42, life());

deps/v8/test/mjsunit/harmony/modules-import-attributes-4.mjs

@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import json from 'modules-skip-1.json' with { type: 'json', notARealAssertion: 'value'};
+
+assertEquals(42, json.life);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-1.mjs

@@ -0,0 +1,12 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', { }).then(namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-10.mjs

@@ -0,0 +1,19 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var result1;
+var result2;
+import('modules-skip-1.json', { get with() { throw 'bad \'with\' getter!'; } }).then(
+    () => assertUnreachable('Should have failed due to throwing getter'),
+    error => result1 = error);
+import('modules-skip-1.json', { with: { get assertionKey() { throw 'bad \'assertionKey\' getter!'; } } }).then(
+    () => assertUnreachable('Should have failed due to throwing getter'),
+    error => result2 = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('bad \'with\' getter!', result1);
+assertEquals('bad \'assertionKey\' getter!', result2);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-11.mjs

@@ -0,0 +1,19 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes --harmony-top-level-await
+
+var life1;
+var life2;
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life1 = namespace.default.life);
+
+// Try loading the same module a second time.
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life2 = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life1);
+assertEquals(42, life2);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-12.mjs

@@ -0,0 +1,26 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+let result1;
+let result2;
+
+let badAssertProxy1 = new Proxy({}, { ownKeys() { throw "bad ownKeys!"; } });
+import('./modules-skip-1.mjs', { with: badAssertProxy1 }).then(
+    () => assertUnreachable('Should have failed due to throwing ownKeys'),
+    error => result1 = error);
+
+let badAssertProxy2 = new Proxy(
+    {foo: "bar"},
+    { getOwnPropertyDescriptor() { throw "bad getOwnPropertyDescriptor!"; } });
+import('./modules-skip-1.mjs', { with: badAssertProxy2 }).then(
+    () => assertUnreachable(
+        'Should have failed due to throwing getOwnPropertyDescriptor'),
+    error => result2 = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('bad ownKeys!', result1);
+assertEquals('bad getOwnPropertyDescriptor!', result2);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-13.mjs

@@ -0,0 +1,26 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+let getters = 0;
+let result;
+
+import('./modules-skip-1.mjs', { with: {
+    get attr1() {
+        getters++;
+        return {};
+    },
+    get attr2() {
+        getters++;
+        return {};
+    },
+} }).then(
+    () => assertUnreachable('Should have failed due to invalid attributes values'),
+    error => result = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(2, getters);
+assertInstanceof(result, TypeError);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-2.mjs

@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', { with: { } }).then(
+    namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);

deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-3.mjs

@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);