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LibJS: Remove [[VarNames]] from GlobalEnvironment

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This is a normative change in the ECMA-262 spec. See:
ed75310
This commit is contained in:
Timothy Flynn 2025-04-28 17:02:01 -04:00 • committed by Tim Flynn
parent 9c85a16aeb
commit 15faaeb2bb
Notes: github-actions[bot] 2025-04-29 11:34:32 +00:00
5 changed files with 35 additions and 51 deletions
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11
Libraries/LibJS/AST.cpp
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@ -1693,17 +1693,16 @@ ThrowCompletionOr<void> Program::global_declaration_instantiation(VM& vm, Global
TRY(for_each_lexically_declared_identifier([&](Identifier const& identifier) -> ThrowCompletionOr<void> {
auto const& name = identifier.string();
// a. If env.HasVarDeclaration(name) is true, throw a SyntaxError exception.
if (global_environment.has_var_declaration(name))
return vm.throw_completion<SyntaxError>(ErrorType::TopLevelVariableAlreadyDeclared, name);
// b. If env.HasLexicalDeclaration(name) is true, throw a SyntaxError exception.
// a. If HasLexicalDeclaration(env, name) is true, throw a SyntaxError exception.
if (global_environment.has_lexical_declaration(name))
return vm.throw_completion<SyntaxError>(ErrorType::TopLevelVariableAlreadyDeclared, name);
// c. Let hasRestrictedGlobal be ? env.HasRestrictedGlobalProperty(name).
// b. Let hasRestrictedGlobal be ? HasRestrictedGlobalProperty(env, name).
auto has_restricted_global = TRY(global_environment.has_restricted_global_property(name));
// c. NOTE: Global var and function bindings (except those that are introduced by non-strict direct eval) are
// non-configurable and are therefore restricted global properties.
// d. If hasRestrictedGlobal is true, throw a SyntaxError exception.
if (has_restricted_global)
return vm.throw_completion<SyntaxError>(ErrorType::RestrictedGlobalProperty, name);

53
Libraries/LibJS/Runtime/GlobalEnvironment.cpp
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@ -146,34 +146,15 @@ ThrowCompletionOr<bool> GlobalEnvironment::delete_binding(VM& vm, FlyString cons
// 6. If existingProp is true, then
if (existing_prop) {
// a. Let status be ? ObjRec.DeleteBinding(N).
bool status = TRY(m_object_record->delete_binding(vm, name));
// b. If status is true, then
if (status) {
// i. Let varNames be envRec.[[VarNames]].
// ii. If N is an element of varNames, remove that element from the varNames.
m_var_names.remove_all_matching([&](auto& entry) { return entry == name; });
}
// c. Return status.
return status;
// a. Return ? ObjRec.DeleteBinding(N).
return TRY(m_object_record->delete_binding(vm, name));
}
// 7. Return true.
return true;
}
// 9.1.1.4.12 HasVarDeclaration ( N ), https://tc39.es/ecma262/#sec-hasvardeclaration
bool GlobalEnvironment::has_var_declaration(FlyString const& name) const
{
// 1. Let varDeclaredNames be envRec.[[VarNames]].
// 2. If varDeclaredNames contains N, return true.
// 3. Return false.
return m_var_names.contains_slow(name);
}
// 9.1.1.4.13 HasLexicalDeclaration ( N ), https://tc39.es/ecma262/#sec-haslexicaldeclaration
// 9.1.1.4.12 HasLexicalDeclaration ( envRec, N ), https://tc39.es/ecma262/#sec-haslexicaldeclaration
bool GlobalEnvironment::has_lexical_declaration(FlyString const& name) const
{
// 1. Let DclRec be envRec.[[DeclarativeRecord]].
@ -181,7 +162,7 @@ bool GlobalEnvironment::has_lexical_declaration(FlyString const& name) const
return MUST(m_declarative_record->has_binding(name));
}
// 9.1.1.4.14 HasRestrictedGlobalProperty ( N ), https://tc39.es/ecma262/#sec-hasrestrictedglobalproperty
// 9.1.1.4.13 HasRestrictedGlobalProperty ( envRec, N ), https://tc39.es/ecma262/#sec-hasrestrictedglobalproperty
ThrowCompletionOr<bool> GlobalEnvironment::has_restricted_global_property(FlyString const& name) const
{
// 1. Let ObjRec be envRec.[[ObjectRecord]].
@ -203,7 +184,7 @@ ThrowCompletionOr<bool> GlobalEnvironment::has_restricted_global_property(FlyStr
return true;
}
// 9.1.1.4.15 CanDeclareGlobalVar ( N ), https://tc39.es/ecma262/#sec-candeclareglobalvar
// 9.1.1.4.14 CanDeclareGlobalVar ( envRec, N ), https://tc39.es/ecma262/#sec-candeclareglobalvar
ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_var(FlyString const& name) const
{
// 1. Let ObjRec be envRec.[[ObjectRecord]].
@ -221,7 +202,7 @@ ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_var(FlyString cons
return global_object.is_extensible();
}
// 9.1.1.4.16 CanDeclareGlobalFunction ( N ), https://tc39.es/ecma262/#sec-candeclareglobalfunction
// 9.1.1.4.15 CanDeclareGlobalFunction ( envRec, N ), https://tc39.es/ecma262/#sec-candeclareglobalfunction
ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_function(FlyString const& name) const
{
// 1. Let ObjRec be envRec.[[ObjectRecord]].
@ -247,7 +228,7 @@ ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_function(FlyString
return false;
}
// 9.1.1.4.17 CreateGlobalVarBinding ( N, D ), https://tc39.es/ecma262/#sec-createglobalvarbinding
// 9.1.1.4.16 CreateGlobalVarBinding ( envRec, N, D ), https://tc39.es/ecma262/#sec-createglobalvarbinding
ThrowCompletionOr<void> GlobalEnvironment::create_global_var_binding(FlyString const& name, bool can_be_deleted)
{
auto& vm = this->vm();
@ -271,18 +252,11 @@ ThrowCompletionOr<void> GlobalEnvironment::create_global_var_binding(FlyString c
TRY(m_object_record->initialize_binding(vm, name, js_undefined(), Environment::InitializeBindingHint::Normal));
}
// 6. Let varDeclaredNames be envRec.[[VarNames]].
// 7. If varDeclaredNames does not contain N, then
if (!m_var_names.contains_slow(name)) {
// a. Append N to varDeclaredNames.
m_var_names.append(name);
}
// 8. Return unused.
// 6. Return UNUSED.
return {};
}
// 9.1.1.4.18 CreateGlobalFunctionBinding ( N, V, D ), https://tc39.es/ecma262/#sec-createglobalfunctionbinding
// 9.1.1.4.17 CreateGlobalFunctionBinding ( envRec, N, V, D ), https://tc39.es/ecma262/#sec-createglobalfunctionbinding
ThrowCompletionOr<void> GlobalEnvironment::create_global_function_binding(FlyString const& name, Value value, bool can_be_deleted)
{
// 1. Let ObjRec be envRec.[[ObjectRecord]].
@ -311,14 +285,7 @@ ThrowCompletionOr<void> GlobalEnvironment::create_global_function_binding(FlyStr
// 7. Perform ? Set(globalObject, N, V, false).
TRY(global_object.set(name, value, Object::ShouldThrowExceptions::Yes));
// 8. Let varDeclaredNames be envRec.[[VarNames]].
// 9. If varDeclaredNames does not contain N, then
if (!m_var_names.contains_slow(name)) {
// a. Append N to varDeclaredNames.
m_var_names.append(name);
}
// 10. Return unused.
// 8. Return UNUSED.
return {};
}

2
Libraries/LibJS/Runtime/GlobalEnvironment.h
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@ -30,7 +30,6 @@ public:
Object& global_this_value() { return *m_global_this_value; }
DeclarativeEnvironment& declarative_record() { return *m_declarative_record; }
bool has_var_declaration(FlyString const& name) const;
bool has_lexical_declaration(FlyString const& name) const;
ThrowCompletionOr<bool> has_restricted_global_property(FlyString const& name) const;
ThrowCompletionOr<bool> can_declare_global_var(FlyString const& name) const;
@ -47,7 +46,6 @@ private:
GC::Ptr<ObjectEnvironment> m_object_record; // [[ObjectRecord]]
GC::Ptr<Object> m_global_this_value; // [[GlobalThisValue]]
GC::Ptr<DeclarativeEnvironment> m_declarative_record; // [[DeclarativeRecord]]
Vector<FlyString> m_var_names; // [[VarNames]]
};
template<>

6
Libraries/LibJS/Tests/eval-redeclaration.js Normal file
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@ -0,0 +1,6 @@
eval("var foo;");
evaluateSource("let foo = 1;");
test("redeclaration of variable in global scope succeeded", () => {
expect(foo).toBe(1);
});

14
Tests/LibJS/test-js.cpp
View file

@ -32,6 +32,20 @@ TESTJS_GLOBAL_FUNCTION(can_parse_source, canParseSource)
return JS::Value(!parser.has_errors());
}
// Based on $262.evalScript
TESTJS_GLOBAL_FUNCTION(evaluate_source, evaluateSource)
{
auto& realm = *vm.current_realm();
auto source = TRY(vm.argument(0).to_string(vm));
auto script = JS::Script::parse(source, realm);
if (script.is_error())
return vm.throw_completion<JS::SyntaxError>(script.error().first().to_string());
return vm.bytecode_interpreter().run(script.value());
}
TESTJS_GLOBAL_FUNCTION(run_queued_promise_jobs, runQueuedPromiseJobs)
{
vm.run_queued_promise_jobs();