fix(core): fix module external not treated as async (#9247)

* fix(core): fix module external not treated as async

* fix: enable async only when module is false

* chore: fix clippy

* reafctor: align build_info.module

Author: hardfist

crates/rspack_core/src/external_module.rs

@@ -533,16 +533,23 @@ impl Module for ExternalModule {
 
   async fn build(
     &mut self,
-    _build_context: BuildContext,
+    build_context: BuildContext,
     _: Option<&Compilation>,
   ) -> Result<BuildResult> {
+    self.build_info.module = build_context.compiler_options.output.module;
     let resolved_external_type = self.resolve_external_type();
 
     // TODO add exports_type for request
     match resolved_external_type {
       "this" => self.build_info.strict = false,
       "system" => self.build_meta.exports_type = BuildMetaExportsType::Namespace,
-      "module" => self.build_meta.exports_type = BuildMetaExportsType::Namespace,
+      "module" => {
+        self.build_meta.exports_type = BuildMetaExportsType::Namespace;
+        // align with https://github.com/webpack/webpack/blob/3919c844eca394d73ca930e4fc5506fb86e2b094/lib/ExternalModule.js#L597
+        if !self.build_info.module {
+          self.build_meta.has_top_level_await = true;
+        }
+      }
       "script" | "promise" => self.build_meta.has_top_level_await = true,
       "import" => {
         self.build_meta.has_top_level_await = true;

crates/rspack_core/src/module.rs

@@ -68,6 +68,7 @@ pub struct BuildInfo {
   pub top_level_declarations: Option<HashSet<Atom>>,
   pub module_concatenation_bailout: Option<String>,
   pub assets: HashMap<String, CompilationAsset>,
+  pub module: bool,
 }
 
 impl Default for BuildInfo {
@@ -87,6 +88,7 @@ impl Default for BuildInfo {
       top_level_declarations: None,
       module_concatenation_bailout: None,
       assets: Default::default(),
+      module: false,
     }
   }
 }
@@ -168,6 +170,7 @@ impl Display for ExportsArgument {
 #[serde(rename_all = "camelCase")]
 pub struct BuildMeta {
   pub strict_esm_module: bool,
+  // same as is_async https://github.com/webpack/webpack/blob/3919c844eca394d73ca930e4fc5506fb86e2b094/lib/Module.js#L107
   pub has_top_level_await: bool,
   pub esm: bool,
   pub exports_type: BuildMetaExportsType,