fix(transformer/legacy-decorator): static class fields cannot be accessed in static field initializer when class-properties plugin is not enabled

crates/oxc_transformer/src/context.rs

@@ -44,6 +44,10 @@ pub struct TransformCtx<'a> {
     pub statement_injector: StatementInjectorStore<'a>,
     /// Manage inserting statements at top of program globally
     pub top_level_statements: TopLevelStatementsStore<'a>,
+
+    // State for multiple plugins interacting
+    /// `true` if class properties plugin is enabled
+    pub is_class_properties_plugin_enabled: bool,
 }
 
 impl TransformCtx<'_> {
@@ -65,6 +69,7 @@ impl TransformCtx<'_> {
             var_declarations: VarDeclarationsStore::new(),
             statement_injector: StatementInjectorStore::new(),
             top_level_statements: TopLevelStatementsStore::new(),
+            is_class_properties_plugin_enabled: options.env.es2022.class_properties.is_some(),
         }
     }
 

crates/oxc_transformer/src/decorator/legacy/mod.rs

@@ -55,7 +55,10 @@ use oxc_span::SPAN;
 use oxc_syntax::operator::AssignmentOperator;
 use oxc_traverse::{Ancestor, BoundIdentifier, Traverse, TraverseCtx};
 
-use crate::{Helper, TransformCtx, utils::ast_builder::create_prototype_member};
+use crate::{
+    Helper, TransformCtx,
+    utils::ast_builder::{create_assignment, create_prototype_member},
+};
 use metadata::LegacyDecoratorMetadata;
 
 #[derive(Default)]
@@ -466,17 +469,52 @@ impl<'a> LegacyDecorator<'a, '_> {
         let mut decoration_stmts =
             self.transform_decorators_of_class_elements(class, &class_binding, ctx);
 
+        let class_alias_with_this_assignment = if self.ctx.is_class_properties_plugin_enabled {
+            None
+        } else {
+            // If we're emitting to ES2022 or later then we need to reassign the class alias before
+            // static initializers are evaluated.
+            // <https://github.com/microsoft/TypeScript/blob/b86ab7dbe0eb2f1c9a624486d72590d638495c97/src/compiler/transformers/legacyDecorators.ts#L345-L366>
+            class_alias_binding.as_ref().and_then(|class_alias_binding| {
+                let has_static_field_or_block = class.body.body.iter().any(|element| {
+                    matches!(element, ClassElement::StaticBlock(_))
+                        || matches!(element, ClassElement::PropertyDefinition(prop)
+                                if prop.r#static
+                        )
+                });
+
+                if has_static_field_or_block {
+                    // `_Class = this`;
+                    let class_alias_with_this_assignment = ctx.ast.statement_expression(
+                        SPAN,
+                        create_assignment(class_alias_binding, ctx.ast.expression_this(SPAN), ctx),
+                    );
+                    let body = ctx.ast.vec1(class_alias_with_this_assignment);
+                    let scope_id = ctx.create_child_scope_of_current(ScopeFlags::ClassStaticBlock);
+                    let element =
+                        ctx.ast.class_element_static_block_with_scope_id(SPAN, body, scope_id);
+                    Some(element)
+                } else {
+                    None
+                }
+            })
+        };
+
         if has_private_in_expression_in_decorator {
             let stmts = mem::replace(&mut decoration_stmts, ctx.ast.vec());
             Self::insert_decorations_into_class_static_block(class, stmts, ctx);
         } else {
             decoration_stmts.push(constructor_decoration);
             self.class_decorated_data = Some(ClassDecoratedData {
                 binding: class_binding,
-                alias_binding: class_alias_binding,
+                alias_binding: class_alias_binding.clone(),
                 decorations: decoration_stmts,
             });
         }
+
+        if let Some(class_alias_with_this_assignment) = class_alias_with_this_assignment {
+            class.body.body.insert(0, class_alias_with_this_assignment);
+        }
     }
 
     /// Transform class to a [`VariableDeclarator`], whose binding name is the same as class.

crates/oxc_transformer/src/lib.rs

@@ -136,13 +136,10 @@ impl<'a> Transformer<'a> {
                 .proposals
                 .explicit_resource_management
                 .then(|| ExplicitResourceManagement::new(&self.ctx)),
-            x0_typescript: program.source_type.is_typescript().then(|| {
-                TypeScript::new(
-                    &self.typescript,
-                    self.env.es2022.class_properties.is_some(),
-                    &self.ctx,
-                )
-            }),
+            x0_typescript: program
+                .source_type
+                .is_typescript()
+                .then(|| TypeScript::new(&self.typescript, &self.ctx)),
             x1_jsx: Jsx::new(self.jsx, self.env.es2018.object_rest_spread, ast_builder, &self.ctx),
             x2_es2022: ES2022::new(
                 self.env.es2022,

crates/oxc_transformer/src/typescript/mod.rs

@@ -51,17 +51,10 @@ pub struct TypeScript<'a, 'ctx> {
     rewrite_extensions: Option<TypeScriptRewriteExtensions>,
     // Options
     remove_class_fields_without_initializer: bool,
-    // State
-    /// Whether class properties plugin is enabled
-    is_class_properties_enabled: bool,
 }
 
 impl<'a, 'ctx> TypeScript<'a, 'ctx> {
-    pub fn new(
-        options: &TypeScriptOptions,
-        is_class_properties_enabled: bool,
-        ctx: &'ctx TransformCtx<'a>,
-    ) -> Self {
+    pub fn new(options: &TypeScriptOptions, ctx: &'ctx TransformCtx<'a>) -> Self {
         Self {
             ctx,
             annotations: TypeScriptAnnotations::new(options, ctx),
@@ -71,7 +64,6 @@ impl<'a, 'ctx> TypeScript<'a, 'ctx> {
             rewrite_extensions: TypeScriptRewriteExtensions::new(options),
             remove_class_fields_without_initializer: !options.allow_declare_fields
                 || options.remove_class_fields_without_initializer,
-            is_class_properties_enabled,
         }
     }
 }
@@ -128,7 +120,9 @@ impl<'a> Traverse<'a> for TypeScript<'a, '_> {
 
         // Avoid converting class fields when class-properties plugin is enabled, that plugin has covered all
         // this transformation does.
-        if !self.is_class_properties_enabled && self.ctx.assumptions.set_public_class_fields {
+        if !self.ctx.is_class_properties_plugin_enabled
+            && self.ctx.assumptions.set_public_class_fields
+        {
             self.transform_class_fields(class, ctx);
         }
     }
@@ -187,7 +181,9 @@ impl<'a> Traverse<'a> for TypeScript<'a, '_> {
         ctx: &mut TraverseCtx<'a>,
     ) {
         self.annotations.enter_method_definition(def, ctx);
-        if self.is_class_properties_enabled || !self.ctx.assumptions.set_public_class_fields {
+        if self.ctx.is_class_properties_plugin_enabled
+            || !self.ctx.assumptions.set_public_class_fields
+        {
             Self::transform_class_constructor(def, ctx);
         }
     }

tasks/transform_conformance/snapshots/oxc.snap.md

@@ -1,6 +1,6 @@
 commit: 578ac4df
 
-Passed: 153/255
+Passed: 153/257
 
 # All Passed:
 * babel-plugin-transform-class-static-block
@@ -497,7 +497,7 @@ after transform: SymbolId(4): ScopeId(1)
 rebuilt        : SymbolId(5): ScopeId(4)
 
 
-# legacy-decorators (4/74)
+# legacy-decorators (4/76)
 * oxc/metadata/abstract-class/input.ts
 Symbol reference IDs mismatch for "Dependency":
 after transform: SymbolId(1): [ReferenceId(1), ReferenceId(2), ReferenceId(3)]
@@ -582,6 +582,46 @@ Symbol span mismatch for "C":
 after transform: SymbolId(3): Span { start: 0, end: 0 }
 rebuilt        : SymbolId(3): Span { start: 106, end: 107 }
 
+* oxc/static-field/input.ts
+Scope children mismatch:
+after transform: ScopeId(0): [ScopeId(1), ScopeId(3), ScopeId(4)]
+rebuilt        : ScopeId(0): [ScopeId(1), ScopeId(3)]
+Scope children mismatch:
+after transform: ScopeId(3): []
+rebuilt        : ScopeId(3): [ScopeId(4)]
+Scope flags mismatch:
+after transform: ScopeId(4): ScopeFlags(ClassStaticBlock)
+rebuilt        : ScopeId(4): ScopeFlags(StrictMode | ClassStaticBlock)
+Scope parent mismatch:
+after transform: ScopeId(4): Some(ScopeId(0))
+rebuilt        : ScopeId(4): Some(ScopeId(3))
+Symbol span mismatch for "Foo":
+after transform: SymbolId(2): Span { start: 103, end: 106 }
+rebuilt        : SymbolId(3): Span { start: 0, end: 0 }
+Symbol reference IDs mismatch for "Foo":
+after transform: SymbolId(2): [ReferenceId(4), ReferenceId(6), ReferenceId(8)]
+rebuilt        : SymbolId(3): [ReferenceId(5), ReferenceId(9)]
+Symbol span mismatch for "Foo":
+after transform: SymbolId(3): Span { start: 0, end: 0 }
+rebuilt        : SymbolId(4): Span { start: 103, end: 106 }
+Unresolved references mismatch:
+after transform: ["ClassDecorator", "babelHelpers", "console"]
+rebuilt        : ["babelHelpers", "console"]
+
+* oxc/static-field-with-class-properties/input.ts
+Symbol span mismatch for "Foo":
+after transform: SymbolId(2): Span { start: 103, end: 106 }
+rebuilt        : SymbolId(3): Span { start: 0, end: 0 }
+Symbol reference IDs mismatch for "Foo":
+after transform: SymbolId(2): [ReferenceId(4), ReferenceId(6), ReferenceId(8), ReferenceId(10)]
+rebuilt        : SymbolId(3): [ReferenceId(4), ReferenceId(6), ReferenceId(10)]
+Symbol span mismatch for "Foo":
+after transform: SymbolId(3): Span { start: 0, end: 0 }
+rebuilt        : SymbolId(4): Span { start: 103, end: 106 }
+Unresolved references mismatch:
+after transform: ["ClassDecorator", "babelHelpers", "console"]
+rebuilt        : ["babelHelpers", "console"]
+
 * oxc/with-class-private-properties/input.ts
 Symbol span mismatch for "C":
 after transform: SymbolId(0): Span { start: 11, end: 12 }

tasks/transform_conformance/snapshots/oxc_exec.snap.md

@@ -2,7 +2,7 @@ commit: 578ac4df
 
 node: v22.14.0
 
-Passed: 6 of 8 (75.00%)
+Passed: 8 of 10 (80.00%)
 
 Failures:
 

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field-with-class-properties/exec.ts

@@ -0,0 +1,10 @@
+function Bar(): ClassDecorator {
+  return (_target) => {
+    console.log(Bar.name)
+  }
+}
+
+@Bar()
+class Foo {
+  static foo = `${Foo.name}`;
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field-with-class-properties/input.ts

@@ -0,0 +1,10 @@
+function Bar(): ClassDecorator {
+  return (_target) => {
+    console.log(Bar.name)
+  }
+}
+
+@Bar()
+class Foo {
+  static foo = `${Foo.name}`;
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field-with-class-properties/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "transform-legacy-decorator",
+    "transform-class-properties"
+  ]
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field-with-class-properties/output.js

@@ -0,0 +1,9 @@
+var _Foo;
+function Bar() {
+  return (_target) => {
+    console.log(Bar.name);
+  };
+}
+let Foo = _Foo = class Foo {};
+babelHelpers.defineProperty(Foo, "foo", `${_Foo.name}`);
+Foo = _Foo = babelHelpers.decorate([Bar()], Foo);

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field/exec.ts

@@ -0,0 +1,10 @@
+function Bar(): ClassDecorator {
+  return (_target) => {
+    console.log(Bar.name)
+  }
+}
+
+@Bar()
+class Foo {
+  static foo = `${Foo.name}`;
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field/input.ts

@@ -0,0 +1,10 @@
+function Bar(): ClassDecorator {
+  return (_target) => {
+    console.log(Bar.name)
+  }
+}
+
+@Bar()
+class Foo {
+  static foo = `${Foo.name}`;
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "transform-legacy-decorator"
+  ]
+}

tasks/transform_conformance/tests/legacy-decorators/test/fixtures/oxc/static-field/output.js

@@ -0,0 +1,13 @@
+var _Foo;
+function Bar() {
+  return (_target) => {
+    console.log(Bar.name);
+  };
+}
+let Foo = _Foo = class Foo {
+  static {
+    _Foo = this;
+  }
+  static foo = `${_Foo.name}`;
+};
+Foo = _Foo = babelHelpers.decorate([Bar()], Foo);