refactor(next-core): remove ast cloning in custom transform (#49560)

### What? - closes WEB-1024. Minor refactoring to avoid explicit AST cloning. Still visitors are using fold though. ### Turbopack changes * https://github.com/vercel/turbo/pull/4869 * https://github.com/vercel/turbo/pull/4879 * https://github.com/vercel/turbo/pull/4881
2023-05-10 02:07:40 -07:00 · 2023-05-10 02:07:40 -07:00 · 1ed7544696
commit 1ed7544696
parent 11a7117d40
7 changed files with 72 additions and 89 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -400,7 +400,7 @@ dependencies = [
 [[package]]
 name = "auto-hash-map"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "serde",
 ]
@ -3413,7 +3413,7 @@ dependencies = [
 [[package]]
 name = "node-file-trace"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "serde",
@ -6980,7 +6980,7 @@ dependencies = [
 [[package]]
 name = "turbo-binding"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "auto-hash-map",
 "mdxjs",
@ -7020,7 +7020,7 @@ dependencies = [
 [[package]]
 name = "turbo-malloc"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "mimalloc",
 ]
@ -7028,7 +7028,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "auto-hash-map",
@ -7058,7 +7058,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-build"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "cargo-lock",
@ -7070,7 +7070,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-bytes"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "bytes",
@ -7085,7 +7085,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-env"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "dotenvy",
@ -7099,7 +7099,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-fetch"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "indexmap",
@ -7116,7 +7116,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-fs"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "auto-hash-map",
@ -7145,7 +7145,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-hash"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "base16",
 "hex",
@ -7157,7 +7157,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-macros"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "convert_case 0.6.0",
@ -7171,7 +7171,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-macros-shared"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "proc-macro2",
 "quote",
@ -7181,7 +7181,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-memory"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "auto-hash-map",
@ -7203,7 +7203,7 @@ dependencies = [
 [[package]]
 name = "turbo-tasks-testing"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "auto-hash-map",
@ -7215,7 +7215,7 @@ dependencies = [
 [[package]]
 name = "turbopack"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-recursion",
@ -7244,7 +7244,7 @@ dependencies = [
 [[package]]
 name = "turbopack-bench"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "chromiumoxide",
@ -7274,7 +7274,7 @@ dependencies = [
 [[package]]
 name = "turbopack-cli-utils"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "clap 4.1.11",
@ -7291,7 +7291,7 @@ dependencies = [
 [[package]]
 name = "turbopack-core"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-trait",
@ -7318,7 +7318,7 @@ dependencies = [
 [[package]]
 name = "turbopack-create-test-app"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "clap 4.1.11",
@ -7331,7 +7331,7 @@ dependencies = [
 [[package]]
 name = "turbopack-css"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-trait",
@ -7353,7 +7353,7 @@ dependencies = [
 [[package]]
 name = "turbopack-dev"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "indexmap",
@ -7374,7 +7374,7 @@ dependencies = [
 [[package]]
 name = "turbopack-dev-server"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-compression",
@ -7408,7 +7408,7 @@ dependencies = [
 [[package]]
 name = "turbopack-ecmascript"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-trait",
@ -7444,11 +7444,15 @@ dependencies = [
 [[package]]
 name = "turbopack-ecmascript-plugins"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-trait",
+ "indexmap",
+ "modularize_imports",
 "serde",
+ "styled_components",
+ "styled_jsx",
 "swc_core",
 "swc_emotion",
 "swc_relay",
@ -7461,7 +7465,7 @@ dependencies = [
 [[package]]
 name = "turbopack-env"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "indexmap",
@ -7477,7 +7481,7 @@ dependencies = [
 [[package]]
 name = "turbopack-image"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "base64 0.21.0",
@ -7497,7 +7501,7 @@ dependencies = [
 [[package]]
 name = "turbopack-json"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "serde",
@ -7512,7 +7516,7 @@ dependencies = [
 [[package]]
 name = "turbopack-mdx"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "mdxjs",
@ -7527,7 +7531,7 @@ dependencies = [
 [[package]]
 name = "turbopack-node"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "async-stream",
@ -7561,7 +7565,7 @@ dependencies = [
 [[package]]
 name = "turbopack-static"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "serde",
@ -7577,7 +7581,7 @@ dependencies = [
 [[package]]
 name = "turbopack-swc-utils"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "swc_core",
 "turbo-tasks",
@ -7588,7 +7592,7 @@ dependencies = [
 [[package]]
 name = "turbopack-test-utils"
 version = "0.1.0"
-source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230508.2#b9e5e6d750c048bb083bfa60941554c479f6685f"
+source = "git+https://github.com/vercel/turbo.git?tag=turbopack-230510.1#95be42aa8a2e9d55207fd8ca8da5e247c2f7f322"
 dependencies = [
 "anyhow",
 "once_cell",
--- a/Cargo.toml
+++ b/Cargo.toml
@ -41,11 +41,11 @@ swc_core = { version = "0.75.41" }
 testing = { version = "0.33.4" }

 # Turbo crates
-turbo-binding = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230508.2" }
+turbo-binding = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230510.1" }
 # [TODO]: need to refactor embed_directory! macro usages, as well as resolving turbo_tasks::function, macros..
-turbo-tasks = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230508.2" }
+turbo-tasks = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230510.1" }
 # [TODO]: need to refactor embed_directory! macro usage in next-core
-turbo-tasks-fs = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230508.2" }
+turbo-tasks-fs = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-230510.1" }

 # General Deps

--- a/packages/next-swc/crates/next-core/src/next_shared/transforms/mod.rs
+++ b/packages/next-swc/crates/next-core/src/next_shared/transforms/mod.rs
@ -9,10 +9,6 @@ pub use next_dynamic::get_next_dynamic_transform_rule;
 pub use next_font::get_next_font_transform_rule;
 pub use next_strip_page_exports::get_next_pages_transforms_rule;
 pub use relay::get_relay_transform_plugin;
-use swc_core::{
-    common::util::take::Take,
-    ecma::ast::{Module, ModuleItem, Program},
-};
 use turbo_binding::turbopack::{
    core::reference_type::{ReferenceType, UrlReferenceSubType},
    turbopack::module_options::{ModuleRule, ModuleRuleCondition, ModuleRuleEffect, ModuleType},
@ -53,18 +49,3 @@ pub(crate) fn module_rule_match_js_no_url() -> ModuleRuleCondition {
        ]),
    ])
 }
-
-pub(crate) fn unwrap_module_program(program: &mut Program) -> Program {
-    match program {
-        Program::Module(module) => Program::Module(module.take()),
-        Program::Script(s) => Program::Module(Module {
-            span: s.span,
-            body: s
-                .body
-                .iter()
-                .map(|stmt| ModuleItem::Stmt(stmt.clone()))
-                .collect(),
-            shebang: s.shebang.clone(),
-        }),
-    }
-}
--- a/packages/next-swc/crates/next-core/src/next_shared/transforms/modularize_imports.rs
+++ b/packages/next-swc/crates/next-core/src/next_shared/transforms/modularize_imports.rs
@ -77,11 +77,7 @@ impl ModularizeImportsTransformer {

 #[async_trait]
 impl CustomTransformer for ModularizeImportsTransformer {
-    async fn transform(
-        &self,
-        program: &mut Program,
-        _ctx: &TransformContext<'_>,
-    ) -> Result<Option<Program>> {
+    async fn transform(&self, program: &mut Program, _ctx: &TransformContext<'_>) -> Result<()> {
        let p = std::mem::replace(program, Program::Module(Module::dummy()));
        *program = p.fold_with(&mut modularize_imports(
            turbo_binding::swc::custom_transform::modularize_imports::Config {
@ -89,6 +85,6 @@ impl CustomTransformer for ModularizeImportsTransformer {
            },
        ));

-        Ok(None)
+        Ok(())
    }
 }
--- a/packages/next-swc/crates/next-core/src/next_shared/transforms/next_dynamic.rs
+++ b/packages/next-swc/crates/next-core/src/next_shared/transforms/next_dynamic.rs
@ -4,8 +4,11 @@ use anyhow::Result;
 use async_trait::async_trait;
 use next_transform_dynamic::{next_dynamic, NextDynamicMode};
 use swc_core::{
-    common::FileName,
-    ecma::{ast::Program, visit::FoldWith},
+    common::{util::take::Take, FileName},
+    ecma::{
+        ast::{Module, Program},
+        visit::FoldWith,
+    },
 };
 use turbo_binding::{
    turbo::tasks_fs::FileSystemPathVc,
@ -18,7 +21,7 @@ use turbo_binding::{
    },
 };

-use super::{module_rule_match_js_no_url, unwrap_module_program};
+use super::module_rule_match_js_no_url;

 /// Returns a rule which applies the Next.js dynamic transform.
 pub async fn get_next_dynamic_transform_rule(
@ -55,19 +58,17 @@ struct NextJsDynamic {

 #[async_trait]
 impl CustomTransformer for NextJsDynamic {
-    async fn transform(
-        &self,
-        program: &mut Program,
-        ctx: &TransformContext<'_>,
-    ) -> Result<Option<Program>> {
-        let module_program = unwrap_module_program(program);
-        Ok(Some(module_program.fold_with(&mut next_dynamic(
+    async fn transform(&self, program: &mut Program, ctx: &TransformContext<'_>) -> Result<()> {
+        let p = std::mem::replace(program, Program::Module(Module::dummy()));
+        *program = p.fold_with(&mut next_dynamic(
            self.is_development,
            self.is_server,
            self.is_server_components,
            NextDynamicMode::Turbo,
            FileName::Real(ctx.file_path_str.into()),
            self.pages_dir.clone(),
-        ))))
+        ));
+
+        Ok(())
    }
 }
--- a/packages/next-swc/crates/next-core/src/next_shared/transforms/next_font.rs
+++ b/packages/next-swc/crates/next-core/src/next_shared/transforms/next_font.rs
@ -38,17 +38,13 @@ struct NextJsFont {

 #[async_trait]
 impl CustomTransformer for NextJsFont {
-    async fn transform(
-        &self,
-        program: &mut Program,
-        ctx: &TransformContext<'_>,
-    ) -> Result<Option<Program>> {
+    async fn transform(&self, program: &mut Program, ctx: &TransformContext<'_>) -> Result<()> {
        let mut next_font = next_transform_font::next_font_loaders(next_transform_font::Config {
            font_loaders: self.font_loaders.clone(),
            relative_file_path_from_root: ctx.file_name_str.into(),
        });

        program.visit_mut_with(&mut next_font);
-        Ok(None)
+        Ok(())
    }
 }
--- a/packages/next-swc/crates/next-core/src/next_shared/transforms/next_strip_page_exports.rs
+++ b/packages/next-swc/crates/next-core/src/next_shared/transforms/next_strip_page_exports.rs
@ -1,7 +1,13 @@
 use anyhow::Result;
 use async_trait::async_trait;
 use next_transform_strip_page_exports::{next_transform_strip_page_exports, ExportFilter};
-use swc_core::ecma::{ast::Program, visit::FoldWith};
+use swc_core::{
+    common::util::take::Take,
+    ecma::{
+        ast::{Module, Program},
+        visit::FoldWith,
+    },
+};
 use turbo_binding::{
    turbo::tasks_fs::FileSystemPathVc,
    turbopack::{
@ -13,7 +19,7 @@ use turbo_binding::{
    },
 };

-use super::{module_rule_match_js_no_url, unwrap_module_program};
+use super::module_rule_match_js_no_url;

 /// Returns a rule which applies the Next.js page export stripping transform.
 pub async fn get_next_pages_transforms_rule(
@ -55,17 +61,16 @@ struct NextJsStripPageExports {

 #[async_trait]
 impl CustomTransformer for NextJsStripPageExports {
-    async fn transform(
-        &self,
-        program: &mut Program,
-        _ctx: &TransformContext<'_>,
-    ) -> Result<Option<Program>> {
+    async fn transform(&self, program: &mut Program, _ctx: &TransformContext<'_>) -> Result<()> {
        // TODO(alexkirsz) Connect the eliminated_packages to telemetry.
        let eliminated_packages = Default::default();

-        let module_program = unwrap_module_program(program);
-        Ok(Some(module_program.fold_with(
-            &mut next_transform_strip_page_exports(self.export_filter, eliminated_packages),
-        )))
+        let p = std::mem::replace(program, Program::Module(Module::dummy()));
+        *program = p.fold_with(&mut next_transform_strip_page_exports(
+            self.export_filter,
+            eliminated_packages,
+        ));
+
+        Ok(())
    }
 }