Support @next/mdx with Turbopack

crates/next-core/src/next_import_map.rs

@@ -806,17 +806,15 @@ async fn insert_next_shared_aliases(
 ) -> Result<()> {
     let package_root = next_js_fs().root();
 
-    if next_config.mdx_rs().await?.is_some() {
-        insert_alias_to_alternatives(
-            import_map,
-            mdx_import_source_file(),
-            vec![
-                request_to_import_mapping(project_path, "./mdx-components"),
-                request_to_import_mapping(project_path, "./src/mdx-components"),
-                request_to_import_mapping(project_path, "@mdx-js/react"),
-            ],
-        );
-    }
+    insert_alias_to_alternatives(
+        import_map,
+        mdx_import_source_file(),
+        vec![
+            request_to_import_mapping(project_path, "./mdx-components"),
+            request_to_import_mapping(project_path, "./src/mdx-components"),
+            request_to_import_mapping(project_path, "@mdx-js/react"),
+        ],
+    );
 
     insert_package_alias(
         import_map,

packages/next-mdx/index.js

@@ -23,6 +23,24 @@ module.exports =
         }
 
     return Object.assign({}, nextConfig, {
+      experimental: Object.assign({}, nextConfig?.experimental, {
+        turbo: Object.assign({}, nextConfig?.experimental?.turbo, {
+          rules: Object.assign({}, nextConfig?.experimental?.turbo?.rules, {
+            '*.mdx': {
+              loaders: [loader],
+              as: '*.tsx',
+            },
+          }),
+          resolveAlias: Object.assign(
+            {},
+            nextConfig?.experimental?.turbo?.resolveAlias,
+            {
+              'next-mdx-import-source-file':
+                '@vercel/turbopack-next/mdx-import-source',
+            }
+          ),
+        }),
+      }),
       webpack(config, options) {
         config.resolve.alias['next-mdx-import-source-file'] = [
           'private-next-root-dir/src/mdx-components',

test/e2e/app-dir/mdx/mdx.test.ts

@@ -1,10 +1,6 @@
 import { nextTestSetup } from 'e2e-utils'
 
-for (const type of [
-  'with-mdx-rs',
-  // only mdx-rs should work with turbopack
-  ...(process.env.TURBOPACK ? [] : ['without-mdx-rs']),
-]) {
+for (const type of ['with-mdx-rs', 'without-mdx-rs']) {
   describe(`mdx ${type}`, () => {
     const { next } = nextTestSetup({
       files: __dirname,

turbopack/crates/turbopack-node/Cargo.toml

@@ -21,6 +21,7 @@ anyhow = { workspace = true }
 async-stream = "0.3.4"
 async-trait = { workspace = true }
 const_format = "0.2.30"
+either = { workspace = true, features = ["serde"] }
 futures = { workspace = true }
 futures-retry = { workspace = true }
 indexmap = { workspace = true, features = ["serde"] }
@@ -33,6 +34,7 @@ regex = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 #serde_qs = { workspace = true }
+serde_with = { workspace = true, features = ["base64"] }
 tokio = { workspace = true, features = ["full"] }
 tracing = { workspace = true }
 turbo-tasks = { workspace = true }

turbopack/crates/turbopack-node/js/src/transforms/webpack-loaders.ts

@@ -468,7 +468,7 @@ const transform = (
         if (!result.result) return reject(new Error("No result from loaders"));
         const [source, map] = result.result;
         resolve({
-          source,
+          source: Buffer.isBuffer(source) ? {binary: source.toString('base64')} : source,
           map:
             typeof map === "string"
               ? map

turbopack/crates/turbopack-node/src/transforms/webpack.rs

@@ -2,8 +2,10 @@ use std::mem::take;
 
 use anyhow::{bail, Context, Result};
 use async_trait::async_trait;
+use either::Either;
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value as JsonValue};
+use serde_with::serde_as;
 use turbo_tasks::{
     trace::TraceRawVcs, Completion, RcStr, TaskInput, TryJoinIterExt, Value, ValueToString, Vc,
 };
@@ -52,11 +54,20 @@ use crate::{
     AssetsForSourceMapping,
 };
 
+#[serde_as]
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
+struct BytesBase64 {
+    #[serde_as(as = "serde_with::base64::Base64")]
+    binary: Vec<u8>,
+}
+
 #[derive(Debug, Serialize, Deserialize, Clone)]
 #[serde(rename_all = "camelCase")]
 #[turbo_tasks::value(serialization = "custom")]
 struct WebpackLoadersProcessingResult {
-    source: RcStr,
+    #[serde(with = "either::serde_untagged")]
+    #[turbo_tasks(debug_ignore, trace_ignore)]
+    source: Either<RcStr, BytesBase64>,
     map: Option<RcStr>,
     #[turbo_tasks(trace_ignore)]
     assets: Option<Vec<EmittedAsset>>,
@@ -250,7 +261,10 @@ impl WebpackLoadersProcessedAsset {
         } else {
             None
         };
-        let file = File::from(processed.source);
+        let file = match processed.source {
+            Either::Left(str) => File::from(str),
+            Either::Right(bytes) => File::from(bytes.binary),
+        };
         let assets = emitted_assets_to_virtual_sources(processed.assets);
         let content = AssetContent::File(FileContent::Content(file).cell()).cell();
         Ok(ProcessWebpackLoadersResult {