From d36f7fd6f865698801510f48b82a6d41b463f98a Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Tue, 24 Dec 2024 12:41:26 +0100
Subject: [PATCH] cli: use commonjs compat mode for .cts files

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 packages/cli/config/nodeTransformHooks.mjs             |  8 +++++---
 .../tests/transforms/__fixtures__/pkg-module/main.ts   |  5 ++---
 packages/cli/src/tests/transforms/transforms.test.ts   | 10 ++--------
 3 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/packages/cli/config/nodeTransformHooks.mjs b/packages/cli/config/nodeTransformHooks.mjs
index 4a897ca6c7..c19738c1ed 100644
--- a/packages/cli/config/nodeTransformHooks.mjs
+++ b/packages/cli/config/nodeTransformHooks.mjs
@@ -246,11 +246,13 @@ export async function load(url, context, nextLoad) {
   // all that well though, and can lead to module loading issues in many cases,
   // especially for older code.
 
-  // This `if` block opts-out of using CommonJS compatibility mode, and instead
-  // leaves it to our existing loader to transform CommonJS.
+  // This `if` block opts-out of using CommonJS compatibility mode by default,
+  // and instead leaves it to our existing loader to transform CommonJS. We do
+  // however use compatibility mode for the more explicit .cts file extension,
+  // allows for a way to opt-in to the new behavior.
   //
   // TODO(Rugvip): Once the synchronous hooks API is available for us to use, we might be able to adopt that instead
-  if (format === 'commonjs') {
+  if (format === 'commonjs' && ext !== '.cts') {
     return nextLoad(url, { ...context, format });
   }
 
diff --git a/packages/cli/src/tests/transforms/__fixtures__/pkg-module/main.ts b/packages/cli/src/tests/transforms/__fixtures__/pkg-module/main.ts
index 4c6c8f0079..56ee59fdd7 100644
--- a/packages/cli/src/tests/transforms/__fixtures__/pkg-module/main.ts
+++ b/packages/cli/src/tests/transforms/__fixtures__/pkg-module/main.ts
@@ -21,13 +21,12 @@ import * as depModule from 'dep-module';
 import * as depDefault from 'dep-default';
 import { value as namedA } from './a-named';
 import { value as namedB } from './b-named';
-import * as cNamed from './c-named';
+import { value as namedC } from './c-named';
 import defaultA from './a-default';
 import defaultB from './b-default';
-import * as cDefault from './c-default';
+import cDefault from './c-default';
 
 const { default: defaultC } = cDefault;
-const { value: namedC } = cNamed;
 
 async function resolveAll(obj): Promise<unknown> {
   const val = await obj;
diff --git a/packages/cli/src/tests/transforms/transforms.test.ts b/packages/cli/src/tests/transforms/transforms.test.ts
index 6f9c291bc7..c15bd063d4 100644
--- a/packages/cli/src/tests/transforms/transforms.test.ts
+++ b/packages/cli/src/tests/transforms/transforms.test.ts
@@ -96,12 +96,7 @@ describe('node runtime module transforms', () => {
       dynCommonJs: expectedExports.commonJs,
       dynDefault: expectedExports.commonJs,
       dynModule: expectedExports.module,
-      // TODO(Rugvip): Fix CommonJS import compat from modules
-      dep: {
-        ...exportValues.all,
-        defaultC: { default: 'c' },
-        namedC: undefined,
-      },
+      dep: exportValues.all,
       dyn: exportValues.all,
     });
   });
@@ -226,8 +221,7 @@ describe('package build transforms', () => {
       dynCommonJs: expectedExports.commonJs,
       dynDefault: expectedExports.commonJs,
       dynModule: expectedExports.module,
-      // TODO(Rugvip): Fix CommonJS import compat from modules
-      dep: { ...exportValues.all, defaultC: { default: 'c' } },
+      dep: exportValues.all,
       dyn: exportValues.all,
     });
   });