Turbopack: respect the module-sync export condition (#93970)

I set it to `::Unknown` because we the runtime may or may not support
module-sync. So let's just trace both for now



There is one problem though:


https://nodejs.org/docs/latest-v26.x/api/packages.html#conditional-exports
> "module-sync" - matches no matter the package is loaded via import,
import() or require(). The format is expected to be ES modules that does
not contain top-level await in its module graph - if it does,
ERR_REQUIRE_ASYNC_MODULE will be thrown when the module is require()-ed.

So we have multiple options:
1. We definitely want to respect module-sync for tracing. We don't
really have to throw ERR_REQUIRE_ASYNC_MODULE here, Node.js will do it
at runtime anyway.
2. ~~What about bundling? Either~~
- ~~Respect module-sync always, but don't throw
ERR_REQUIRE_ASYNC_MODULE.~~
- ~~Respect module-sync always, and do throw a build error the module
requires TLA. This would require a separate validation pass though.~~
   - I'm not enabling it for bundling for now

turbopack/crates/turbopack-core/src/resolve/options.rs

@@ -39,9 +39,12 @@ pub enum ResolveModules {
     },
 }
 
-#[derive(TraceRawVcs, Hash, PartialEq, Eq, Clone, Copy, Debug, NonLocalValue, Encode, Decode)]
+#[derive(
+    TraceRawVcs, Hash, PartialEq, Eq, Clone, Copy, Debug, NonLocalValue, Encode, Decode, Default,
+)]
 pub enum ConditionValue {
     Set,
+    #[default]
     Unset,
     Unknown,
 }

turbopack/crates/turbopack-nft/src/nft.rs

@@ -22,6 +22,7 @@ use turbopack_core::{
     output::{OutputAsset, OutputAssetsReference},
     reference::all_assets_from_entries,
     reference_type::ReferenceType,
+    resolve::options::ConditionValue,
     traced_asset::TracedAsset,
 };
 use turbopack_ecmascript::AnalyzeMode;
@@ -109,6 +110,7 @@ async fn node_file_trace_operation(
             enable_node_native_modules: true,
             enable_node_modules: Some(input_dir),
             custom_conditions: vec![rcstr!("node")],
+            module_sync: ConditionValue::Unknown,
             enable_node_externals: true,
             loose_errors: true,
             collect_affecting_sources: true,

turbopack/crates/turbopack-resolve/src/ecmascript.rs

@@ -66,6 +66,9 @@ async fn apply_esm_specific_options_internal(
     for conditions in get_condition_maps(&mut options) {
         conditions.insert(rcstr!("import"), ConditionValue::Set);
         conditions.insert(rcstr!("require"), ConditionValue::Unset);
+        // Don't set "module-sync" to ConditionValue::Set here. When tracing, the Node.js runtime
+        // version might not support it yet, so we still want the "import"/"require"/"default"
+        // result anyway.
     }
 
     if clear_extensions {
@@ -83,6 +86,9 @@ pub async fn apply_cjs_specific_options(options: Vc<ResolveOptions>) -> Result<V
     for conditions in get_condition_maps(&mut options) {
         conditions.insert(rcstr!("import"), ConditionValue::Unset);
         conditions.insert(rcstr!("require"), ConditionValue::Set);
+        // Don't set "module-sync" to ConditionValue::Set here. When tracing, the Node.js runtime
+        // version might not support it yet, so we still want the "import"/"require"/"default"
+        // result anyway.
     }
     Ok(options.cell())
 }

turbopack/crates/turbopack-resolve/src/resolve.rs

@@ -88,6 +88,9 @@ async fn base_resolve_options(
         if opt.module {
             conditions.insert(rcstr!("module"), ConditionValue::Set);
         }
+        if opt.module_sync != ConditionValue::Unset {
+            conditions.insert(rcstr!("module-sync"), opt.module_sync);
+        }
         if let Some(environment) = emulating {
             for condition in environment.resolve_conditions().await?.iter() {
                 conditions.insert(condition.clone(), ConditionValue::Set);

turbopack/crates/turbopack-resolve/src/resolve_options_context.rs

@@ -7,7 +7,7 @@ use turbopack_core::{
     condition::ContextCondition,
     environment::Environment,
     resolve::{
-        options::{ImportMap, ResolvedMap},
+        options::{ConditionValue, ImportMap, ResolvedMap},
         plugin::{AfterResolvePlugin, BeforeResolvePlugin},
     },
 };
@@ -53,6 +53,8 @@ pub struct ResolveOptionsContext {
     pub browser: bool,
     /// Enables the "module" field and export condition in package.json
     pub module: bool,
+    /// Enables the "module-sync" export condition in package.json
+    pub module_sync: ConditionValue,
     pub custom_conditions: Vec<RcStr>,
     pub custom_extensions: Option<Vec<RcStr>>,
     /// An additional import map to use when resolving modules.

turbopack/crates/turbopack-tracing/tests/node-file-trace.rs

@@ -51,6 +51,7 @@ use turbopack_core::{
     rebase::RebasedAsset,
     reference::all_assets_from_entry,
     reference_type::ReferenceType,
+    resolve::options::ConditionValue,
 };
 use turbopack_ecmascript::AnalyzeMode;
 use turbopack_resolve::resolve_options_context::ResolveOptionsContext;
@@ -414,6 +415,7 @@ async fn node_file_trace_operation(
             enable_node_native_modules: true,
             enable_node_modules: Some(input_dir.clone()),
             custom_conditions: vec![rcstr!("node")],
+            module_sync: ConditionValue::Unknown,
             collect_affecting_sources: true,
             ..Default::default()
         }

turbopack/crates/turbopack-tracing/tests/node-file-trace/test/unit/imports-module-sync/output.js

@@ -1,6 +1,7 @@
 ;[
   'test/unit/imports-module-sync/input.js',
-  'test/unit/imports-module-sync/internal-default.js',
+  // @vercel/nft outputs internal-default.js here instead, but I think that's wrong?
+  'test/unit/imports-module-sync/internal-import.js',
   'test/unit/imports-module-sync/internal-sync.js',
   'test/unit/imports-module-sync/package.json',
 ]

turbopack/crates/turbopack-tracing/tests/node-file-trace/test/unit/module-sync-condition-es-nested/output.js

@@ -1,5 +1,6 @@
 ;[
-  'test/unit/module-sync-condition-es-nested/fallback.js',
+  // @vercel/nft outputs fallback.js here instead, but I think that's wrong?
+  'test/unit/module-sync-condition-es-nested/import.js',
   'test/unit/module-sync-condition-es-nested/input.js',
   'test/unit/module-sync-condition-es-nested/module-sync.js',
   'test/unit/module-sync-condition-es-nested/package.json',

turbopack/crates/turbopack-tracing/tests/node-file-trace/test/unit/module-sync-condition-es/output.js

@@ -1,5 +1,6 @@
 ;[
-  'test/unit/module-sync-condition-es/fallback.js',
+  // @vercel/nft outputs fallback.js here instead, but I think that's wrong?
+  'test/unit/module-sync-condition-es/import.js',
   'test/unit/module-sync-condition-es/input.js',
   'test/unit/module-sync-condition-es/module-sync.js',
   'test/unit/module-sync-condition-es/package.json',

turbopack/crates/turbopack-tracing/tests/node-file-trace/test/unit/self-reference-module-sync/output.js

@@ -1,5 +1,6 @@
 ;[
-  'test/unit/self-reference-module-sync/default.js',
+  // @vercel/nft outputs default.js here instead, but I think that's wrong?
+  'test/unit/self-reference-module-sync/import.js',
   'test/unit/self-reference-module-sync/input.js',
   'test/unit/self-reference-module-sync/module-sync.js',
   'test/unit/self-reference-module-sync/package.json',

turbopack/crates/turbopack-tracing/tests/unit.rs

@@ -30,6 +30,7 @@ use turbopack_core::{
     output::OutputAsset,
     reference::all_assets_from_entries,
     reference_type::ReferenceType,
+    resolve::options::ConditionValue,
     traced_asset::TracedAsset,
 };
 use turbopack_ecmascript::AnalyzeMode;
@@ -108,8 +109,8 @@ static ALLOC: turbo_tasks_malloc::TurboMalloc = turbo_tasks_malloc::TurboMalloc;
 // #[case::import_meta_tpl_cnd("import-meta-tpl-cnd")]
 #[case::import_meta_url("import-meta-url")]
 // #[case::imports("imports")]
-// #[case::imports_module_sync("imports-module-sync")]
-// #[case::imports_module_sync_cjs("imports-module-sync-cjs")]
+#[case::imports_module_sync("imports-module-sync")]
+#[case::imports_module_sync_cjs("imports-module-sync-cjs")]
 // #[case::jsonc_parser_wrapper("jsonc-parser-wrapper")]
 // #[case::jsx_input("jsx-input")]
 // #[case::microtime_node_gyp("microtime-node-gyp")]
@@ -123,10 +124,12 @@ static ALLOC: turbo_tasks_malloc::TurboMalloc = turbo_tasks_malloc::TurboMalloc;
 #[case::module_create_require_no_mixed("module-create-require-no-mixed")]
 // #[case::module_register("module-register")]
 // #[case::module_require("module-require")]
-// #[case::module_sync_condition_cjs("module-sync-condition-cjs")]
+#[case::module_sync_condition_cjs("module-sync-condition-cjs")]
+// Turbopack always includes the module-sync version, regardless of the current Node version
 // #[case::module_sync_condition_cjs_node20("module-sync-condition-cjs-node20")]
-// #[case::module_sync_condition_es("module-sync-condition-es")]
-// #[case::module_sync_condition_es_nested("module-sync-condition-es-nested")]
+#[case::module_sync_condition_es("module-sync-condition-es")]
+#[case::module_sync_condition_es_nested("module-sync-condition-es-nested")]
+// Turbopack always includes the module-sync version, regardless of the current Node version
 // #[case::module_sync_condition_es_node20("module-sync-condition-es-node20")]
 // #[case::mongoose("mongoose")]
 // #[case::multi_input("multi-input")]
@@ -165,7 +168,7 @@ static ALLOC: turbo_tasks_malloc::TurboMalloc = turbo_tasks_malloc::TurboMalloc;
 // #[case::resolve_from("resolve-from")]
 // #[case::resolve_hook("resolve-hook")]
 // #[case::return_emission("return-emission")]
-// #[case::self_reference_module_sync("self-reference-module-sync")]
+#[case::self_reference_module_sync("self-reference-module-sync")]
 // #[case::shiki("shiki")]
 // #[case::string_concat("string-concat")]
 #[case::syntax_err("syntax-err")]
@@ -250,6 +253,7 @@ async fn node_file_trace_operation(package_root: RcStr, input: RcStr) -> Result<
             enable_node_native_modules: true,
             enable_node_modules: Some(input_dir.clone()),
             custom_conditions: vec![rcstr!("node")],
+            module_sync: ConditionValue::Unknown,
             ..Default::default()
         }
         .cell(),

turbopack/crates/turbopack/src/lib.rs

@@ -36,8 +36,11 @@ use turbopack_core::{
     },
     resolve::{
         ExternalTraced, ExternalType, ModulePart, ModuleResolveResult, ModuleResolveResultItem,
-        ResolveResult, ResolveResultItem, options::ResolveOptions, origin::PlainResolveOrigin,
-        parse::Request, resolve,
+        ResolveResult, ResolveResultItem,
+        options::{ConditionValue, ResolveOptions},
+        origin::PlainResolveOrigin,
+        parse::Request,
+        resolve,
     },
     source::Source,
     source_transform::SourceTransforms,
@@ -926,6 +929,7 @@ pub async fn externals_tracing_module_context(
         loose_errors: true,
         collect_affecting_sources: true,
         custom_conditions: vec![rcstr!("node")],
+        module_sync: ConditionValue::Unknown,
         ..Default::default()
     };