fix(webpack): handle relative paths for additionalEntryPath (#27885)

The `NxAppWebpackPlugin` does not support relative paths in
`additionalEntryPoints`.

So this will fail:

```js
new NxAppWebpackPlugin({
  ...
  additionalEntryPoints: ['.src/foo.ts']
```

The resolved path is relative to workspace root when it should be
project root.

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## Current Behavior
Build will fail.
## Expected Behavior
Build should work.

## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->

Fixes #

e2e/webpack/src/webpack.test.ts

@@ -132,8 +132,12 @@ describe('Webpack Plugin', () => {
 
   it('should be able to build with NxWebpackPlugin and a standard webpack config file', () => {
     const appName = uniq('app');
-    runCLI(`generate @nx/web:app ${appName} --bundler webpack`);
+    runCLI(
+      `generate @nx/web:app ${appName} --bundler webpack --directory=apps/${appName} --projectNameAndRootFormat=as-provided`
+    );
     updateFile(`apps/${appName}/src/main.ts`, `console.log('Hello');\n`);
+    updateFile(`apps/${appName}/src/foo.ts`, `console.log('Foo');\n`);
+    updateFile(`apps/${appName}/src/bar.ts`, `console.log('Bar');\n`);
 
     updateFile(
       `apps/${appName}/webpack.config.js`,
@@ -144,13 +148,20 @@ describe('Webpack Plugin', () => {
       module.exports = {
         target: 'node',
         output: {
-          path: path.join(__dirname, '../../dist/${appName}')
+          path: path.join(__dirname, '../../dist/apps/${appName}')
         },
         plugins: [
           new NxAppWebpackPlugin({
             compiler: 'tsc',
-            main: 'apps/${appName}/src/main.ts',
-            tsConfig: 'apps/${appName}/tsconfig.app.json',
+            main: './src/main.ts',
+            additionalEntryPoints: [
+              './src/foo.ts',
+              {
+                entryName: 'bar',
+                entryPath: './src/bar.ts', 
+              }
+            ],
+            tsConfig: './tsconfig.app.json',
             outputHashing: 'none',
             optimization: false,
           })
@@ -160,8 +171,9 @@ describe('Webpack Plugin', () => {
 
     runCLI(`build ${appName}`);
 
-    let output = runCommand(`node dist/${appName}/main.js`);
-    expect(output).toMatch(/Hello/);
+    expect(runCommand(`node dist/apps/${appName}/main.js`)).toMatch(/Hello/);
+    expect(runCommand(`node dist/apps/${appName}/foo.js`)).toMatch(/Foo/);
+    expect(runCommand(`node dist/apps/${appName}/bar.js`)).toMatch(/Bar/);
   }, 500_000);
 
   it('should bundle in NX_PUBLIC_ environment variables', () => {

packages/webpack/src/plugins/nx-webpack-plugin/lib/normalize-options.ts

@@ -1,4 +1,4 @@
-import { basename, dirname, join, relative, resolve } from 'path';
+import { basename, dirname, join, parse, relative, resolve } from 'path';
 import { statSync } from 'fs';
 import {
   normalizePath,
@@ -204,6 +204,18 @@ function normalizeRelativePaths(
   for (const [fieldName, fieldValue] of Object.entries(options)) {
     if (isRelativePath(fieldValue)) {
       options[fieldName] = join(projectRoot, fieldValue);
+    } else if (fieldName === 'additionalEntryPoints') {
+      for (let i = 0; i < fieldValue.length; i++) {
+        const v = fieldValue[i];
+        if (isRelativePath(v)) {
+          fieldValue[i] = {
+            entryName: parse(v).name,
+            entryPath: join(projectRoot, v),
+          };
+        } else if (isRelativePath(v.entryPath)) {
+          v.entryPath = join(projectRoot, v.entryPath);
+        }
+      }
     } else if (Array.isArray(fieldValue)) {
       for (let i = 0; i < fieldValue.length; i++) {
         if (isRelativePath(fieldValue[i])) {