fix: partial fix for #21997 & #22004, throw the originalError

npm/webpack-dev-server/package.json

@@ -46,4 +46,4 @@
   "files": [
     "dist"
   ]
-}
+}

packages/server/lib/plugins/child/run_require_async_child.js

@@ -97,10 +97,12 @@ function run (ipc, file, projectRoot) {
     //   3a. Yes: Use bundleRequire
     //   3b. No: Continue through to `await import(configFile)`
     // 4. Use node's dynamic import to import the configFile
+    let originalError
 
     try {
       return require(file)
     } catch (err) {
+      originalError = err
       if (!err.stack.includes('[ERR_REQUIRE_ESM]') && !err.stack.includes('SyntaxError: Cannot use import statement outside a module')) {
         throw err
       }
@@ -122,8 +124,16 @@ function run (ipc, file, projectRoot) {
         debug(`User doesn't have esbuild. Going to use native node imports.`)
 
         // We cannot replace the initial `require` with `await import` because
-        // Certain modules cannot be dynamically imported
-        return await import(file)
+        // Certain modules cannot be dynamically imported. If this throws, however, we want
+        // to show the original error that was thrown, because that's ultimately the source of the problem
+        try {
+          return await import(file)
+        } catch (e) {
+          // If we aren't able to import the file at all, throw the original error, since that has more accurate information
+          // of what failed to begin with
+          debug('esbuild fallback for loading config failed, throwing original error. esbuild error: %o', e)
+          throw originalError
+        }
       }
 
       throw err

system-tests/__snapshots__/config_modules_spec.ts.js

@@ -0,0 +1,3 @@
+exports['cypress config with esm and cjs / does not support modules and ts without esbuild in config-cjs-and-esm/config-with-ts-module'] = `
+STDOUT_ERROR_VALIDATED
+`

system-tests/test/config_modules_spec.ts

@@ -32,6 +32,13 @@ describe('cypress config with esm and cjs', function () {
       spec: 'app.cy.js',
       browser: 'chrome',
       expectedExitCode: 1,
+      snapshot: true,
+      onStdout (stdout) {
+        expect(stdout).to.include('nearest parent package.json contains "type": "module" which defines all .ts files in that package scope as ES modules')
+
+        // Need to make this stable b/c of filepaths, and snapshot: true is needed to invoke onStdout
+        return 'STDOUT_ERROR_VALIDATED'
+      },
     })
   })