fix(es/decorators): Fix bugs of 2022-03 implementation (#9145)

**Description:**

I extracted some changes from #8970

crates/swc/src/config/mod.rs

@@ -42,6 +42,7 @@ use swc_ecma_minifier::option::terser::TerserTopLevelOptions;
 #[allow(deprecated)]
 pub use swc_ecma_parser::JscTarget;
 use swc_ecma_parser::{parse_file_as_expr, Syntax, TsSyntax};
+pub use swc_ecma_transforms::proposals::DecoratorVersion;
 use swc_ecma_transforms::{
  feature::FeatureFlag,
  hygiene, modules,
@@ -676,6 +677,18 @@ impl Options {
  {
  Box::new(plugin_transforms)
  } else {
+ let decorator_pass: Box<dyn Fold> =
+ match transform.decorator_version.unwrap_or_default() {
+ DecoratorVersion::V202112 => Box::new(decorators(decorators::Config {
+ legacy: transform.legacy_decorator.into_bool(),
+ emit_metadata: transform.decorator_metadata.into_bool(),
+ use_define_for_class_fields: !assumptions.set_public_class_fields,
+ })),
+ DecoratorVersion::V202203 => Box::new(
+ swc_ecma_transforms::proposals::decorator_2022_03::decorator_2022_03(),
+ ),
+ };
+
  Box::new(chain!(
  lint_to_fold(swc_ecma_lints::rules::all(LintParams {
  program: &program,
@@ -686,23 +699,7 @@ impl Options {
  source_map: cm.clone(),
  })),
  // Decorators may use type information
- Optional::new(
- match transform.decorator_version.unwrap_or_default() {
- DecoratorVersion::V202112 => {
- Either::Left(decorators(decorators::Config {
- legacy: transform.legacy_decorator.into_bool(),
- emit_metadata: transform.decorator_metadata.into_bool(),
- use_define_for_class_fields: !assumptions.set_public_class_fields,
- }))
- }
- DecoratorVersion::V202203 => {
- Either::Right(
- swc_ecma_transforms::proposals::decorator_2022_03::decorator_2022_03(),
- )
- }
- },
- syntax.decorators()
- ),
+ Optional::new(decorator_pass, syntax.decorators()),
  Optional::new(
  explicit_resource_management(),
  syntax.explicit_resource_management()
@@ -1446,17 +1443,6 @@ pub struct TransformConfig {
  pub decorator_version: Option<DecoratorVersion>,
 }
 
-#[derive(Debug, Default, Clone, Copy, Serialize, Deserialize)]
-#[serde(deny_unknown_fields, rename_all = "camelCase")]
-pub enum DecoratorVersion {
- #[default]
- #[serde(rename = "2021-12")]
- V202112,
-
- #[serde(rename = "2022-03")]
- V202203,
-}
-
 #[derive(Debug, Default, Clone, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct HiddenTransformConfig {

crates/swc_ecma_transforms_proposal/src/decorator_2022_03.rs

@@ -13,11 +13,11 @@ use swc_ecma_utils::{
 use swc_ecma_visit::{as_folder, noop_visit_mut_type, Fold, VisitMut, VisitMutWith};
 
 pub fn decorator_2022_03() -> impl VisitMut + Fold {
- as_folder(Decorator202203::default())
+ as_folder(Decorator2022_03::default())
 }
 
 #[derive(Default)]
-struct Decorator202203 {
+struct Decorator2022_03 {
  /// Variables without initializer.
  extra_vars: Vec<VarDeclarator>,
 
@@ -35,6 +35,8 @@ struct Decorator202203 {
 
 #[derive(Default)]
 struct ClassState {
+ private_id_index: u32,
+
  static_lhs: Vec<Ident>,
  proto_lhs: Vec<Ident>,
 
@@ -55,7 +57,7 @@ struct ClassState {
  super_class: Option<Ident>,
 }
 
-impl Decorator202203 {
+impl Decorator2022_03 {
  fn preserve_side_effect_of_decorators(
  &mut self,
  decorators: Vec<Decorator>,
@@ -463,6 +465,7 @@ impl Decorator202203 {
  let has_static_member = body.iter().any(|m| match m {
  ClassMember::Method(m) => m.is_static,
  ClassMember::PrivateMethod(m) => m.is_static,
+ ClassMember::AutoAccessor(m) => m.is_static,
  ClassMember::ClassProp(ClassProp { is_static, .. })
  | ClassMember::PrivateProp(PrivateProp { is_static, .. }) => *is_static,
  ClassMember::StaticBlock(_) => true,
@@ -527,7 +530,9 @@ impl Decorator202203 {
 
  for m in body.iter_mut() {
  match m {
- ClassMember::ClassProp(..) | ClassMember::PrivateProp(..) => {
+ ClassMember::ClassProp(..)
+ | ClassMember::PrivateProp(..)
+ | ClassMember::AutoAccessor(..) => {
  replace_ident(m, c.ident.to_id(), &new_class_name);
  }
 
@@ -568,6 +573,13 @@ impl Decorator202203 {
  p.is_static = false;
  }
  }
+
+ ClassMember::AutoAccessor(p) => {
+ if p.is_static {
+ should_move = true;
+ p.is_static = false;
+ }
+ }
  _ => (),
  }
 
@@ -753,7 +765,7 @@ impl Decorator202203 {
  }
 }
 
-impl VisitMut for Decorator202203 {
+impl VisitMut for Decorator2022_03 {
  noop_visit_mut_type!();
 
  fn visit_mut_class(&mut self, n: &mut Class) {
@@ -932,6 +944,8 @@ impl VisitMut for Decorator202203 {
  for mut m in members.take() {
  match m {
  ClassMember::AutoAccessor(mut accessor) => {
+ accessor.value.visit_mut_with(self);
+
  let name;
  let init;
  let field_name_like: JsWord;
@@ -947,9 +961,14 @@ impl VisitMut for Decorator202203 {
  init = private_ident!(format!("_init_{}", k.id.sym));
  field_name_like = format!("__{}", k.id.sym).into();
 
+ self.state.private_id_index += 1;
  PrivateName {
  span: k.span,
- id: Ident::new(format!("__{}", k.id.sym).into(), k.id.span),
+ id: Ident::new(
+ format!("__{}_{}", k.id.sym, self.state.private_id_index)
+ .into(),
+ k.id.span,
+ ),
  }
  }
  Key::Public(k) => {
@@ -958,10 +977,16 @@ impl VisitMut for Decorator202203 {
  .replacen("init", "private", 1)
  .into();
 
+ self.state.private_id_index += 1;
+
  PrivateName {
  span: init.span.with_ctxt(SyntaxContext::empty()),
  id: Ident::new(
- field_name_like.clone(),
+ format!(
+ "{field_name_like}_{}",
+ self.state.private_id_index
+ )
+ .into(),
  init.span.with_ctxt(SyntaxContext::empty()),
  ),
  }
@@ -1310,7 +1335,9 @@ impl VisitMut for Decorator202203 {
 
  for mut m in new.take() {
  match m {
- ClassMember::Method(..) | ClassMember::PrivateMethod(..) => {}
+ ClassMember::Method(..)
+ | ClassMember::PrivateMethod(..)
+ | ClassMember::AutoAccessor(..) => {}
 
  _ => {
  if !m.span().is_dummy() {

crates/swc_ecma_transforms_proposal/src/lib.rs

@@ -1,11 +1,24 @@
 #![deny(clippy::all)]
 #![allow(clippy::vec_box)]
 
+use serde::{Deserialize, Serialize};
+
 pub use self::{
  decorators::decorators, export_default_from::export_default_from,
  import_assertions::import_assertions,
 };
 
+#[derive(Debug, Default, Clone, Copy, Serialize, Deserialize)]
+#[serde(deny_unknown_fields, rename_all = "camelCase")]
+pub enum DecoratorVersion {
+ #[default]
+ #[serde(rename = "2021-12")]
+ V202112,
+
+ #[serde(rename = "2022-03")]
+ V202203,
+}
+
 pub mod decorator_2022_03;
 pub mod decorators;
 pub mod explicit_resource_management;

crates/swc_ecma_transforms_proposal/tests/decorator-evanw-split/Class-decorators-Binding-initialization-class-expression.js

@@ -0,0 +1,39 @@
+(() => {
+ let old;
+ let block;
+ class Bar {
+ }
+ const dec = (cls, ctx) => {
+ old = cls;
+ return Bar;
+ };
+ const Foo = 
+ @dec
+ class Foo {
+ static { block = Foo; }
+ method() { return Foo; }
+ static method() { return Foo; }
+ field = Foo;
+ static field = Foo;
+ get getter() { return Foo; }
+ static get getter() { return Foo; }
+ set setter(x) { x.foo = Foo; }
+ static set setter(x) { x.foo = Foo; }
+ accessor accessor = Foo;
+ static accessor accessor = Foo;
+ };
+ const foo = new old;
+ let obj;
+ assertEq(() => Foo !== old, true);
+ assertEq(() => Foo, Bar);
+ assertEq(() => block, Bar);
+ assertEq(() => Foo.field, Bar);
+ assertEq(() => foo.field, Bar);
+ assertEq(() => old.getter, Bar);
+ assertEq(() => foo.getter, Bar);
+ assertEq(() => (obj = { foo: null }, old.setter = obj, obj.foo), Bar);
+ assertEq(() => (obj = { foo: null }, foo.setter = obj, obj.foo), Bar);
+ // The specification for accessors is potentially wrong at the moment: https://github.com/tc39/proposal-decorators/issues/529
+ // assertEq(() => old.accessor, Bar)
+ // assertEq(() => foo.accessor, Bar)
+})();

crates/swc_ecma_transforms_proposal/tests/decorator-evanw-split/Class-decorators-Binding-initialization-class-statement.js

@@ -0,0 +1,38 @@
+(() => {
+ let old;
+ let block;
+ class Bar {
+ }
+ const dec = (cls, ctx) => {
+ old = cls;
+ return Bar;
+ };
+ @dec
+ class Foo {
+ static { block = Foo; }
+ method() { return Foo; }
+ static method() { return Foo; }
+ field = Foo;
+ static field = Foo;
+ get getter() { return Foo; }
+ static get getter() { return Foo; }
+ set setter(x) { x.foo = Foo; }
+ static set setter(x) { x.foo = Foo; }
+ accessor accessor = Foo;
+ static accessor accessor = Foo;
+ }
+ const foo = new old;
+ let obj;
+ assertEq(() => Foo !== old, true);
+ assertEq(() => Foo, Bar);
+ assertEq(() => block, Bar);
+ assertEq(() => Foo.field, Bar);
+ assertEq(() => foo.field, Bar);
+ assertEq(() => old.getter, Bar);
+ assertEq(() => foo.getter, Bar);
+ assertEq(() => (obj = { foo: null }, old.setter = obj, obj.foo), Bar);
+ assertEq(() => (obj = { foo: null }, foo.setter = obj, obj.foo), Bar);
+ // The specification for accessors is potentially wrong at the moment: https://github.com/tc39/proposal-decorators/issues/529
+ // assertEq(() => old.accessor, Bar)
+ // assertEq(() => foo.accessor, Bar)
+})();

crates/swc_ecma_transforms_proposal/tests/decorator-evanw-split/Decorator-metadata-class-expression.js

@@ -65,4 +65,23 @@
  assertEq(() => Object.getPrototypeOf(foo), null);
  assertEq(() => order(bar), '0,1,2,3,11,12,13,14,4,5,6,7,15,16,17,18,8,19,9,20,10,21');
  assertEq(() => Object.getPrototypeOf(bar), foo);
+ // Test an undecorated class
+ const FooNoDec = class {
+ };
+ const BarNoDec = class extends FooNoDec {
+ };
+ assertEq(() => FooNoDec[Symbol.metadata], null);
+ assertEq(() => BarNoDec[Symbol.metadata], null);
+ // Test a class with no class decorator
+ const FooOneDec = class {
+ @dec
+ x;
+ };
+ const BarOneDec = class extends FooOneDec {
+ @dec
+ y;
+ };
+ assertEq(() => JSON.stringify(FooOneDec[Symbol.metadata]), JSON.stringify({ x: 22 }));
+ assertEq(() => JSON.stringify(BarOneDec[Symbol.metadata]), JSON.stringify({ y: 23 }));
+ assertEq(() => Object.getPrototypeOf(BarOneDec[Symbol.metadata]), FooOneDec[Symbol.metadata]);
 })();

crates/swc_ecma_transforms_proposal/tests/decorator-evanw-split/Decorator-metadata-class-statement.js

@@ -64,4 +64,23 @@
  assertEq(() => Object.getPrototypeOf(foo), null);
  assertEq(() => order(bar), '0,1,2,3,11,12,13,14,4,5,6,7,15,16,17,18,8,19,9,20,10,21');
  assertEq(() => Object.getPrototypeOf(bar), foo);
+ // Test an undecorated class
+ class FooNoDec {
+ }
+ class BarNoDec extends FooNoDec {
+ }
+ assertEq(() => FooNoDec[Symbol.metadata], null);
+ assertEq(() => BarNoDec[Symbol.metadata], null);
+ // Test a class with no class decorator
+ class FooOneDec {
+ @dec
+ x;
+ }
+ class BarOneDec extends FooOneDec {
+ @dec
+ y;
+ }
+ assertEq(() => JSON.stringify(FooOneDec[Symbol.metadata]), JSON.stringify({ x: 22 }));
+ assertEq(() => JSON.stringify(BarOneDec[Symbol.metadata]), JSON.stringify({ y: 23 }));
+ assertEq(() => Object.getPrototypeOf(BarOneDec[Symbol.metadata]), FooOneDec[Symbol.metadata]);
 })();