fix(cjs): should keep correct esm semantic in importing external modules

crates/rolldown/src/ast_scanner/mod.rs

@@ -297,8 +297,10 @@ impl<'me> AstScanner<'me> {
       let record_id = self.add_import_record(&source.value, ImportKind::Import);
       decl.specifiers.iter().for_each(|spec| {
         self.add_re_export(spec.exported.name(), spec.local.name(), record_id);
-        self.result.imports.insert(decl.span, record_id);
       });
+      self.result.imports.insert(decl.span, record_id);
+      // `export {} from '...'`
+      self.result.import_records[record_id].is_plain_import = decl.specifiers.is_empty();
     } else {
       decl.specifiers.iter().for_each(|spec| {
         self.add_local_export(spec.exported.name(), self.get_root_binding(spec.local.name()));
@@ -358,25 +360,29 @@ impl<'me> AstScanner<'me> {
   }
 
   fn scan_import_decl(&mut self, decl: &ImportDeclaration) {
-    let id = self.add_import_record(&decl.source.value, ImportKind::Import);
-    self.result.imports.insert(decl.span, id);
+    let rec_id = self.add_import_record(&decl.source.value, ImportKind::Import);
+    self.result.imports.insert(decl.span, rec_id);
+    // // `import '...'` or `import {} from '...'`
+    self.result.import_records[rec_id].is_plain_import =
+      decl.specifiers.as_ref().map_or(true, |s| s.is_empty());
+
     let Some(specifiers) = &decl.specifiers else { return };
     specifiers.iter().for_each(|spec| match spec {
       oxc::ast::ast::ImportDeclarationSpecifier::ImportSpecifier(spec) => {
         let sym = spec.local.expect_symbol_id();
         let imported = spec.imported.name();
-        self.add_named_import(sym, imported, id);
+        self.add_named_import(sym, imported, rec_id);
         if imported == "default" {
-          self.result.import_records[id].contains_import_default = true;
+          self.result.import_records[rec_id].contains_import_default = true;
         }
       }
       oxc::ast::ast::ImportDeclarationSpecifier::ImportDefaultSpecifier(spec) => {
-        self.add_named_import(spec.local.expect_symbol_id(), "default", id);
-        self.result.import_records[id].contains_import_default = true;
+        self.add_named_import(spec.local.expect_symbol_id(), "default", rec_id);
+        self.result.import_records[rec_id].contains_import_default = true;
       }
       oxc::ast::ast::ImportDeclarationSpecifier::ImportNamespaceSpecifier(spec) => {
-        self.add_star_import(spec.local.expect_symbol_id(), id);
-        self.result.import_records[id].contains_import_star = true;
+        self.add_star_import(spec.local.expect_symbol_id(), rec_id);
+        self.result.import_records[rec_id].contains_import_star = true;
       }
     });
   }

crates/rolldown/src/stages/link_stage/mod.rs

@@ -241,6 +241,12 @@ impl<'a> LinkStage<'a> {
             ModuleId::External(_) => {
               // Make sure symbols from external modules are included and de_conflicted
               stmt_info.side_effect = true;
+              if matches!(self.input_options.format, OutputFormat::Cjs)
+                && matches!(rec.kind, ImportKind::Import)
+                && !rec.is_plain_import
+              {
+                stmt_info.referenced_symbols.push(self.runtime.resolve_symbol("__toESM"));
+              }
             }
             ModuleId::Normal(importee_id) => {
               let importee_linking_info = &self.metas[importee_id];

crates/rolldown/src/utils/chunk/render_chunk_imports.rs

@@ -87,8 +87,12 @@ pub fn render_chunk_imports(
   });
 
   // render external imports
-
   let imports_from_external_modules = &chunk.imports_from_external_modules;
+
+  if imports_from_external_modules.is_empty() {
+    return s;
+  }
+
   imports_from_external_modules.iter().for_each(|(importee_id, named_imports)| {
     let importee = &graph.module_table.external_modules[*importee_id];
     let mut is_importee_imported = false;
@@ -106,7 +110,11 @@ pub fn render_chunk_imports(
                 s.push_str(&format!("import * as {alias} from \"{importee_name}\";\n",));
               }
               rolldown_common::OutputFormat::Cjs => {
-                s.push_str(&format!("const {alias} = require(\"{importee_name}\");\n",));
+                let to_esm_fn_name = &chunk.canonical_names
+                  [&graph.symbols.par_canonical_ref_for(graph.runtime.resolve_symbol("__toESM"))];
+                s.push_str(&format!(
+                  "const {alias} = {to_esm_fn_name}(require(\"{importee_name}\"));\n",
+                ));
               }
             }
 
@@ -118,7 +126,24 @@ pub fn render_chunk_imports(
       .collect::<Vec<_>>();
     import_items.sort();
     if !import_items.is_empty() {
-      render_import_stmt(&import_items, &importee.name, &mut s);
+      match options.format {
+        rolldown_common::OutputFormat::Esm => {
+          s.push_str(&format!(
+            "import {{ {} }} from \"{importee_module_specifier}\";\n",
+            import_items.join(", "),
+            importee_module_specifier = &importee.name
+          ));
+        }
+        rolldown_common::OutputFormat::Cjs => {
+          let to_esm_fn_name = &chunk.canonical_names
+            [&graph.symbols.par_canonical_ref_for(graph.runtime.resolve_symbol("__toESM"))];
+          s.push_str(&format!(
+            "const {{ {} }} = {to_esm_fn_name}(require(\"{importee_module_specifier}\"));\n",
+            import_items.join(", "),
+            importee_module_specifier = &importee.name
+          ));
+        }
+      }
     } else if !is_importee_imported {
       // Ensure the side effect
       render_plain_import(&importee.name, &mut s);

crates/rolldown/tests/esbuild/default/import_fs_node_common_js/_config.json

@@ -8,7 +8,5 @@
     ],
     "format": "cjs",
     "external": ["fs"]
-  },
-  "_comment": "TODO: support excution of cjs format",
-  "expectExecuted": false
+  }
 }

crates/rolldown/tests/esbuild/default/import_fs_node_common_js/artifacts.snap

@@ -8,8 +8,9 @@ input_file: crates/rolldown/tests/esbuild/default/import_fs_node_common_js
 ## entry_js.cjs
 
 ```js
-const fs = require("fs");
-const { default: defaultValue, readFileSync } = require("fs");
+const { __toESM } = require("./$runtime$.cjs");
+const fs = __toESM(require("fs"));
+const { default: defaultValue, readFileSync } = __toESM(require("fs"));
 
 // entry.js
 console.log(fs, readFileSync, defaultValue);

crates/rolldown/tests/esbuild/import_star/re_export_star_as_external_common_js/artifacts.snap

@@ -16,7 +16,8 @@ input_file: crates/rolldown/tests/esbuild/import_star/re_export_star_as_external
 ## entry_js.cjs
 
 ```js
-const out = require("foo");
+const { __toESM } = require("./$runtime$.cjs");
+const out = __toESM(require("foo"));
 
 exports.out = out;
 ```

crates/rolldown/tests/esbuild/import_star/re_export_star_external_common_js/artifacts.snap

@@ -16,5 +16,6 @@ input_file: crates/rolldown/tests/esbuild/import_star/re_export_star_external_co
 ## entry_js.cjs
 
 ```js
+const { __toESM } = require("./$runtime$.cjs");
 require("foo");
 ```

crates/rolldown/tests/fixtures/function/format/cjs/plain_import_should_not_introduce_to_esm/_config.json

@@ -0,0 +1,7 @@
+{
+  "config": {
+    "format": "cjs",
+    "external": ["foo", "bar", "baz"]
+  },
+  "expectExecuted": false
+}

crates/rolldown/tests/fixtures/function/format/cjs/plain_import_should_not_introduce_to_esm/artifacts.snap

@@ -0,0 +1,14 @@
+---
+source: crates/rolldown/tests/common/case.rs
+expression: content
+input_file: crates/rolldown/tests/fixtures/function/format/cjs/plain_import_should_not_introduce_to_esm
+---
+# Assets
+
+## main.cjs
+
+```js
+require("foo");
+require("bar");
+require("baz");
+```

crates/rolldown/tests/fixtures/function/format/cjs/plain_import_should_not_introduce_to_esm/main.js

@@ -0,0 +1,3 @@
+import 'foo'
+import {} from 'bar'
+export {} from 'baz'

crates/rolldown/tests/snapshots/fixtures__filename_with_hash.snap

@@ -177,7 +177,8 @@ expression: "snapshot_outputs.join(\"\\n\")"
 
 # tests/esbuild/default/import_fs_node_common_js
 
-- entry_js-!~{000}~.cjs => entry_js-TE_F6vZL.cjs
+- $runtime$-!~{001}~.cjs => $runtime$-OBYYRk4K.cjs
+- entry_js-!~{000}~.cjs => entry_js-98OoslfP.cjs
 
 # tests/esbuild/default/import_missing_common_js
 
@@ -531,7 +532,8 @@ expression: "snapshot_outputs.join(\"\\n\")"
 
 # tests/esbuild/import_star/re_export_star_as_external_common_js
 
-- entry_js-!~{000}~.cjs => entry_js-xqfVgBNO.cjs
+- $runtime$-!~{001}~.cjs => $runtime$-OBYYRk4K.cjs
+- entry_js-!~{000}~.cjs => entry_js-lO9-PfCm.cjs
 
 # tests/esbuild/import_star/re_export_star_as_external_es6
 
@@ -544,7 +546,8 @@ expression: "snapshot_outputs.join(\"\\n\")"
 
 # tests/esbuild/import_star/re_export_star_external_common_js
 
-- entry_js-!~{000}~.cjs => entry_js-rud5zVrH.cjs
+- $runtime$-!~{001}~.cjs => $runtime$-OBYYRk4K.cjs
+- entry_js-!~{000}~.cjs => entry_js-XWUyJeqD.cjs
 
 # tests/esbuild/import_star/re_export_star_external_es6
 
@@ -1240,6 +1243,10 @@ expression: "snapshot_outputs.join(\"\\n\")"
 - main-!~{000}~.mjs => main-LeJVwZoF.mjs
 - share-!~{002}~.mjs => share-eIGIrVeP.mjs
 
+# tests/fixtures/function/format/cjs/plain_import_should_not_introduce_to_esm
+
+- main-!~{000}~.cjs => main-rClOc9Ow.cjs
+
 # tests/fixtures/function/resolve/browser_filed_false
 
 - $runtime$-!~{001}~.mjs => $runtime$-aUKPtNTY.mjs

crates/rolldown_common/src/types/import_record.rs

@@ -52,6 +52,7 @@ pub struct RawImportRecord {
   pub namespace_ref: SymbolRef,
   pub contains_import_star: bool,
   pub contains_import_default: bool,
+  pub is_plain_import: bool,
 }
 
 impl RawImportRecord {
@@ -62,6 +63,7 @@ impl RawImportRecord {
       namespace_ref,
       contains_import_default: false,
       contains_import_star: false,
+      is_plain_import: false,
     }
   }
 
@@ -73,6 +75,7 @@ impl RawImportRecord {
       namespace_ref: self.namespace_ref,
       contains_import_star: self.contains_import_star,
       contains_import_default: self.contains_import_default,
+      is_plain_import: self.is_plain_import,
     }
   }
 }
@@ -86,4 +89,5 @@ pub struct ImportRecord {
   pub namespace_ref: SymbolRef,
   pub contains_import_star: bool,
   pub contains_import_default: bool,
+  pub is_plain_import: bool,
 }