refactor(rust): make NormalizedBundlerOptions#external optional (#829)

crates/rolldown/src/module_loader/normal_module_task.rs

@@ -211,24 +211,25 @@ impl NormalModuleTask {
     options: HookResolveIdExtraOptions,
   ) -> BatchedResult<ResolvedRequestInfo> {
     // Check external with unresolved path
-    if input_options.external.call(specifier.to_string(), Some(importer.to_string()), false).await?
-    {
-      return Ok(ResolvedRequestInfo {
-        path: specifier.to_string().into(),
-        module_type: ModuleType::Unknown,
-        is_external: true,
-      });
+    if let Some(external) = input_options.external.as_ref() {
+      if external.call(specifier.to_string(), Some(importer.to_string()), false).await? {
+        return Ok(ResolvedRequestInfo {
+          path: specifier.to_string().into(),
+          module_type: ModuleType::Unknown,
+          is_external: true,
+        });
+      }
     }
 
     let mut info =
       resolve_id(resolver, plugin_driver, specifier, Some(importer), options, false).await?;
 
     if !info.is_external {
       // Check external with resolved path
-      info.is_external = input_options
-        .external
-        .call(specifier.to_string(), Some(importer.to_string()), true)
-        .await?;
+      if let Some(external) = input_options.external.as_ref() {
+        info.is_external =
+          external.call(specifier.to_string(), Some(importer.to_string()), true).await?;
+      }
     }
     Ok(info)
   }

crates/rolldown/src/utils/normalize_options.rs

@@ -16,7 +16,7 @@ pub fn normalize_options(mut raw_options: crate::BundlerOptions) -> NormalizeOpt
     cwd: raw_options
       .cwd
       .unwrap_or_else(|| std::env::current_dir().expect("Failed to get current dir")),
-    external: raw_options.external.unwrap_or_default(),
+    external: raw_options.external,
     treeshake: raw_options.treeshake.unwrap_or(true),
     platform: raw_options.platform.unwrap_or(Platform::Browser),
     entry_file_names: raw_options

crates/rolldown_binding/src/utils/normalize_binding_options.rs

@@ -34,22 +34,19 @@ pub fn normalize_binding_options(
   debug_assert!(PathBuf::from(&input_options.cwd) != PathBuf::from("/"), "{input_options:#?}");
   let cwd = PathBuf::from(input_options.cwd);
 
-  let external = input_options
-    .external
-    .map(|ts_fn| {
-      rolldown::External::Fn(Box::new(move |source, importer, is_resolved| {
-        let ts_fn = ts_fn.clone();
-        Box::pin(async move {
-          ts_fn.call_async((source, importer, is_resolved)).await.map_err(BuildError::from)
-        })
-      }))
-    })
-    .unwrap_or_default();
+  let external = input_options.external.map(|ts_fn| {
+    rolldown::External::Fn(Box::new(move |source, importer, is_resolved| {
+      let ts_fn = ts_fn.clone();
+      Box::pin(async move {
+        ts_fn.call_async((source, importer, is_resolved)).await.map_err(BuildError::from)
+      })
+    }))
+  });
 
   let bundler_options = BundlerOptions {
     input: Some(input_options.input.into_iter().map(Into::into).collect()),
     cwd: cwd.into(),
-    external: external.into(),
+    external,
     treeshake: true.into(),
     resolve: input_options.resolve.map(Into::into),
     platform: input_options

crates/rolldown_common/src/inner_bundler_options/types/external.rs

@@ -26,12 +26,6 @@ impl Debug for External {
   }
 }
 
-impl Default for External {
-  fn default() -> Self {
-    Self::ArrayString(vec![])
-  }
-}
-
 impl External {
   pub async fn call(
     &self,

crates/rolldown_common/src/inner_bundler_options/types/normalized_bundler_options.rs

@@ -14,7 +14,7 @@ pub struct NormalizedBundlerOptions {
   // --- Input
   pub input: Vec<InputItem>,
   pub cwd: PathBuf,
-  pub external: External,
+  pub external: Option<External>,
   pub treeshake: bool,
   pub platform: Platform,
   pub shim_missing_exports: bool,