Stop overriding the user's TS config with defaults during next build (

#45670)

## Bug

The `next build` command is silently overriding the user's tsconfig when
it shouldn't be; this results in mismatched behavior between `tsc
--noEmit` and `yarn build` and user confusion.

For example, a configuration option like `"moduleResolution":
"nodenext"`, which is preserved and respected by `next dev`, will be
silently overridden to `"moduleResolution": "node"` during `next build`.

This change:
- Fixes #38854
- (probably fixes) #45452 (I have not verified)
- (probably fixes) #41189 (I have not verified)

## Details

Next has a concept of both _defaults_ and _permitted options_ when
modifying/validating the user's tsconfig. The user's config is only
modified if it does not match the _permitted options_. This means that
if the user has specified a permitted value like `"moduleResolution":
"nodenext"`, it will not be overwritten in the user's config file.

However, there was some logic in `runTypeCheck.ts` that did not
adequately capture this nuance – instead, it spread all of the defaults
into the tsconfig it was building before running typecheck, which meant
that if a user had specified an option that was _permitted_ but
_non-default_, it would be overwritten, silently, during `yarn build`
only.

Because Next is already (1) rewriting the TSconfig in
`writeConfigurationDefaults` when the user's config doesn't line up with
what we're expecting and (2) verifying the user's TSConfig remains
correct (in `verifyTypeScriptSetup`) during a `next build`, I believe
that it is safe to remove this config-steamrolling behavior.

## Documentation / Examples

I believe this is strictly a bugfix; it updates the behavior of `next
build` to conform to the same configuration behavior exhibited by `tsc
--noEmit` and `next dev`. Since this is already the user expectation, it
should not require documentation changes.

---------

Co-authored-by: Shu Ding <g@shud.in>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/next/src/lib/typescript/runTypeCheck.ts

@@ -41,8 +41,8 @@ export async function runTypeCheck(
   const requiredConfig = getRequiredConfiguration(ts)
 
   const options = {
-    ...effectiveConfiguration.options,
     ...requiredConfig,
+    ...effectiveConfiguration.options,
     declarationMap: false,
     emitDeclarationOnly: false,
     noEmit: true,

test/integration/tsconfig-verifier/pages/index.tsx

@@ -1,6 +1,6 @@
-// eslint-disable-next-line @typescript-eslint/no-unused-vars
+/* eslint-disable @typescript-eslint/no-unused-vars */
 const blah: boolean = false
-// eslint-disable-next-line @typescript-eslint/no-unused-vars
-const blah2 = import('../value').then((r) => r.default)
+// @ts-expect-error ignore the import issue here caused by https://github.com/microsoft/TypeScript/issues/49083
+const blah2 = import('../value.ts').then((r) => r.default)
 
 export default () => <h3>Hello TypeScript</h3>

test/production/supports-module-resolution-nodenext/pages/index.tsx

@@ -0,0 +1,5 @@
+import helloWorldString from 'pkg/sub-export'
+
+export default function Page() {
+  return <p>{helloWorldString}</p>
+}

test/production/supports-module-resolution-nodenext/pkg/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "pkg",
+  "version": "1.0.0",
+  "type": "module",
+  "exports": {
+    "./sub-export": "./src/some-file.js"
+  }
+}

test/production/supports-module-resolution-nodenext/pkg/src/some-file.d.ts

@@ -0,0 +1,2 @@
+declare const _default: 'Hello, world'
+export default _default

test/production/supports-module-resolution-nodenext/pkg/src/some-file.js

@@ -0,0 +1 @@
+export default 'Hello, world'

test/production/supports-module-resolution-nodenext/supports-moduleresolution-nodenext.test.ts

@@ -0,0 +1,26 @@
+import { createNextDescribe, FileRef } from 'e2e-utils'
+import { join } from 'path'
+
+// regression test suite for https://github.com/vercel/next.js/issues/38854
+createNextDescribe(
+  'Does not override tsconfig moduleResolution field during build',
+  {
+    packageJson: { type: 'module' },
+    files: {
+      'tsconfig.json': new FileRef(join(__dirname, 'tsconfig.json')),
+      pages: new FileRef(join(__dirname, 'pages')),
+      pkg: new FileRef(join(__dirname, 'pkg')),
+    },
+    dependencies: {
+      typescript: 'latest',
+      '@types/react': 'latest',
+      '@types/node': 'latest',
+      pkg: './pkg',
+    },
+  },
+  ({ next }) => {
+    it('boots and renders without throwing an error', async () => {
+      await next.render$('/')
+    })
+  }
+)

test/production/supports-module-resolution-nodenext/tsconfig.json

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "esModuleInterop": true,
+    "module": "esnext",
+    "jsx": "preserve",
+    "target": "es5",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "noEmit": true,
+    "incremental": true,
+    "moduleResolution": "nodenext",
+    "resolveJsonModule": true,
+    "isolatedModules": true
+  },
+  "exclude": ["node_modules"],
+  "include": ["next-env.d.ts", "components", "pages"]
+}