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fix(turbopack): honor legacy targets in export callbacks #211

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Merged
fireairforce merged 1 commit into from
Nov 10, 2026
Merged

fix(turbopack): honor legacy targets in export callbacks #211

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137 changes: 95 additions & 42 deletions turbopack/crates/turbopack-ecmascript/src/references/esm/export.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1005,6 +1005,28 @@ struct CompactReexports {
subsume_imports: bool,
}

fn export_getter(value: Expr, supports_arrow_functions: bool) -> Expr {
if supports_arrow_functions {
quote!("() => $value" as Expr, value: Expr = value)
} else {
quote!("function() { return $value; }" as Expr, value: Expr = value)
}
}

fn export_setter(target: AssignTarget, parameter: Ident, supports_arrow_functions: bool) -> Expr {
if supports_arrow_functions {
quote!("($new) => $target = $new" as Expr,
target: AssignTarget = target,
new = parameter,
)
} else {
quote!("function($new) { return $target = $new; }" as Expr,
target: AssignTarget = target,
new = parameter,
)
}
}

impl EsmExports {
pub(crate) async fn code_generation(
self: Vc<Self>,
Expand All @@ -1021,6 +1043,13 @@ impl EsmExports {
.module_export_usage(*ResolvedVc::upcast(module))
.await?;
let expanded = self.expand_exports(*export_usage_info.export_usage).await?;
// Export registration is generated after source transforms. Its callbacks must obey
// the target too, including live bindings in transform helpers and module cycles.
let supports_arrow_functions = *chunking_context
.environment()
.runtime_versions()
.supports_arrow_functions()
.await?;

if scope_hoisting_context.skip_module_exports() && expanded.dynamic_exports.is_empty() {
// If the current module is not exposed, no need to generate exports.
Expand Down Expand Up @@ -1117,9 +1146,17 @@ impl EsmExports {
continue;
}
let exprs: ExportBinding = match local {
EsmExport::Error => ExportBinding::Getter(quote!(
"(() => { throw new Error(\"Failed binding. See build errors!\"); })" as Expr,
)),
EsmExport::Error => ExportBinding::Getter(if supports_arrow_functions {
quote!(
"(() => { throw new Error(\"Failed binding. See build errors!\"); })"
as Expr
)
} else {
quote!(
"(function() { throw new Error(\"Failed binding. See build errors!\"); })"
as Expr
)
}),
EsmExport::LocalBinding(name, liveness) => {
// TODO ideally, this information would just be stored in
// EsmExport::LocalBinding and we wouldn't have to re-correlated this
Expand Down Expand Up @@ -1155,15 +1192,15 @@ impl EsmExports {
(Liveness::Constant, false) => ExportBinding::Value(Expr::Ident(local)),
// If the value might change or we are a circuit breaker we must bind a
// getter to avoid capturing the value at the wrong time.
(Liveness::Live, _) | (Liveness::Constant, true) => {
ExportBinding::Getter(quote!("() => $local" as Expr, local = local))
}
(Liveness::Live, _) | (Liveness::Constant, true) => ExportBinding::Getter(
export_getter(local.into(), supports_arrow_functions),
),
(Liveness::Mutable, _) => ExportBinding::GetterSetter(
quote!("() => $local" as Expr, local = local.clone()),
quote!(
"($new) => $local = $new" as Expr,
local: AssignTarget = AssignTarget::Simple(local.into()),
new = Ident::new(format!("new_{name}").into(), DUMMY_SP, ctxt),
export_getter(local.clone().into(), supports_arrow_functions),
export_setter(
AssignTarget::Simple(local.into()),
Ident::new(format!("new_{name}").into(), DUMMY_SP, ctxt),
supports_arrow_functions,
),
),
}
Expand All @@ -1186,21 +1223,31 @@ impl EsmExports {
},
} if export_usage_info.is_circuit_breaker => {
let id = asset.chunk_item_id(chunking_context).await?;
quote!(
"($namespace ?? $turbopack_import($id))[$export]" as Expr,
namespace = Ident::new(
namespace_ident.as_str().into(),
DUMMY_SP,
ctxt.unwrap_or_default(),
),
turbopack_import: Expr = TURBOPACK_IMPORT.into(),
id: Expr = module_id_to_lit(&id),
let namespace = Ident::new(
namespace_ident.as_str().into(),
DUMMY_SP,
ctxt.unwrap_or_default(),
);
let namespace = if supports_arrow_functions {
quote!("$namespace ?? $turbopack_import($id)" as Expr,
namespace = namespace,
turbopack_import: Expr = TURBOPACK_IMPORT.into(),
id: Expr = module_id_to_lit(&id),
)
} else {
quote!("$namespace == null ? $turbopack_import($id) : $namespace" as Expr,
namespace = namespace,
turbopack_import: Expr = TURBOPACK_IMPORT.into(),
id: Expr = module_id_to_lit(&id),
)
};
quote!("($namespace)[$export]" as Expr,
namespace: Expr = namespace,
export: Expr = Lit::Str(Str {
span: DUMMY_SP,
value: export.as_str().into(),
raw: None,
})
.into(),
}).into(),
)
}
_ => {
Expand All @@ -1225,9 +1272,10 @@ impl EsmExports {
// In the constant case, we could still export as a value if
// we knew that the module
// came _before_ us, but we don't at this point.
ExportBinding::Getter(
quote!("() => $local" as Expr, local: Expr = read_expr),
)
ExportBinding::Getter(export_getter(
read_expr,
supports_arrow_functions,
))
}
(Liveness::Mutable, _) => {
let assign_target = AssignTarget::Simple(
Expand All @@ -1240,11 +1288,18 @@ impl EsmExports {
.into_inner(),
);
ExportBinding::GetterSetter(
quote!("() => $local" as Expr, local: Expr= read_expr.clone()),
quote!(
"($new) => $lhs = $new" as Expr,
lhs: AssignTarget = assign_target,
new = Ident::new(format!("new_{name}").into(), DUMMY_SP, *ctxt),
export_getter(
read_expr.clone(),
supports_arrow_functions,
),
export_setter(
assign_target,
Ident::new(
format!("new_{name}").into(),
DUMMY_SP,
*ctxt,
),
supports_arrow_functions,
),
)
}
Expand All @@ -1256,24 +1311,22 @@ impl EsmExports {
// The namespace variable can still be undefined while a cyclic
// dependency is evaluating this getter. In that case, import the
// module directly so we read from its already-created namespace.
let getter = quote!(
"() => $expr" as Expr,
expr: Expr = read_expr.clone()
);
let getter =
export_getter(read_expr.clone(), supports_arrow_functions);
let assign_target =
AssignTarget::try_from(Box::new(read_expr.clone()))
.expect("imported binding must be assignable");
if *mutable {
ExportBinding::GetterSetter(
getter,
quote!(
"($new) => $lhs = $new" as Expr,
lhs: AssignTarget = assign_target,
new = Ident::new(
export_setter(
assign_target,
Ident::new(
format!("new_{name}").into(),
DUMMY_SP,
Default::default()
Default::default(),
),
supports_arrow_functions,
),
)
} else {
Expand All @@ -1294,9 +1347,9 @@ impl EsmExports {
.map(|ident| {
let imported = ident.as_expr(DUMMY_SP, false);
if export_usage_info.is_circuit_breaker {
ExportBinding::Getter(quote!(
"(() => $imported)" as Expr,
imported: Expr = imported
ExportBinding::Getter(export_getter(
imported,
supports_arrow_functions,
))
} else {
ExportBinding::Value(imported)
Expand Down