Ensure build trace is correct with extra entries

packages/next/build/webpack/plugins/next-trace-entrypoints-plugin.ts

@@ -76,13 +76,12 @@ export class TraceEntryPointsPlugin implements webpack.Plugin {
       assets[traceOutputName] = new sources.RawSource(
         JSON.stringify({
           version: TRACE_OUTPUT_VERSION,
-          files: [...entryFiles, ...this.entryTraces.get(entrypoint.name)!].map(
-            (file) => {
-              return nodePath
-                .relative(traceOutputPath, file)
-                .replace(/\\/g, '/')
-            }
-          ),
+          files: [
+            ...entryFiles,
+            ...(this.entryTraces.get(entrypoint.name) || []),
+          ].map((file) => {
+            return nodePath.relative(traceOutputPath, file).replace(/\\/g, '/')
+          }),
         })
       )
     }
@@ -118,22 +117,35 @@ export class TraceEntryPointsPlugin implements webpack.Plugin {
           // over the compilation modules list
           const entryNameMap = new Map<string, string>()
           const entryModMap = new Map<string, any>()
+          const additionalEntries = new Map<string, Map<string, any>>()
 
           try {
             const depModMap = new Map<string, any>()
 
             compilation.entries.forEach((entry) => {
               const name = entry.name || entry.options?.name
 
-              if (name?.startsWith('pages/') && entry.dependencies[0]) {
-                const entryMod = getModuleFromDependency(
-                  compilation,
-                  entry.dependencies[0]
-                )
+              if (name?.replace(/\\/g, '/').startsWith('pages/')) {
+                for (const dep of entry.dependencies) {
+                  if (!dep) continue
+                  const entryMod = getModuleFromDependency(compilation, dep)
+
+                  if (entryMod && entryMod.resource) {
+                    if (
+                      entryMod.resource.replace(/\\/g, '/').includes('pages/')
+                    ) {
+                      entryNameMap.set(entryMod.resource, name)
+                      entryModMap.set(entryMod.resource, entryMod)
+                    } else {
+                      let curMap = additionalEntries.get(name)
 
-                if (entryMod.resource) {
-                  entryNameMap.set(entryMod.resource, name)
-                  entryModMap.set(entryMod.resource, entryMod)
+                      if (!curMap) {
+                        curMap = new Map()
+                        additionalEntries.set(name, curMap)
+                      }
+                      curMap.set(entryMod.resource, entryMod)
+                    }
+                  }
                 }
               }
             })
@@ -225,6 +237,13 @@ export class TraceEntryPointsPlugin implements webpack.Plugin {
 
               const toTrace: string[] = [entry, ...depModMap.keys()]
 
+              const entryName = entryNameMap.get(entry)!
+              const curExtraEntries = additionalEntries.get(entryName)
+
+              if (curExtraEntries) {
+                toTrace.push(...curExtraEntries.keys())
+              }
+
               const root = nodePath.parse(process.cwd()).root
               const result = await nodeFileTrace(toTrace, {
                 base: root,
@@ -249,7 +268,7 @@ export class TraceEntryPointsPlugin implements webpack.Plugin {
               //   version: TRACE_OUTPUT_VERSION,
               //   tracedDeps,
               // }
-              this.entryTraces.set(entryNameMap.get(entry)!, tracedDeps)
+              this.entryTraces.set(entryName, tracedDeps)
             }
 
             callback()

test/integration/build-trace-extra-entries/content/hello.json

@@ -0,0 +1,3 @@
+{
+  "hello": "world"
+}

test/integration/build-trace-extra-entries/lib/get-data.js

@@ -0,0 +1,8 @@
+import fs from 'fs'
+import path from 'path'
+
+export function getData() {
+  return JSON.parse(
+    fs.readFileSync(path.join(process.cwd(), 'content/hello.json'), 'utf8')
+  )
+}

test/integration/build-trace-extra-entries/next.config.js

@@ -0,0 +1,25 @@
+const path = require('path')
+
+module.exports = {
+  experimental: {
+    nftTracing: true,
+  },
+  webpack(cfg, { isServer }) {
+    console.log(cfg.entry)
+    const origEntry = cfg.entry
+    cfg.entry = async () => {
+      const origEntries = await origEntry()
+
+      if (isServer) {
+        const curEntry = origEntries['pages/_app']
+        origEntries['pages/_app'] = [
+          path.resolve('lib/get-data.js'),
+          ...curEntry,
+        ]
+        console.log(origEntries)
+      }
+      return origEntries
+    }
+    return cfg
+  },
+}

test/integration/build-trace-extra-entries/pages/index.js

@@ -0,0 +1,3 @@
+export default function Page() {
+  return 'index page'
+}

test/integration/build-trace-extra-entries/test/index.test.js

@@ -0,0 +1,32 @@
+/* eslint-env jest */
+
+import fs from 'fs-extra'
+import { join } from 'path'
+import { nextBuild } from 'next-test-utils'
+
+jest.setTimeout(1000 * 60)
+
+const appDir = join(__dirname, '..')
+
+describe('build trace with extra entries', () => {
+  it('should build and trace correctly', async () => {
+    const result = await nextBuild(appDir, undefined, {
+      cwd: appDir,
+    })
+    expect(result.code).toBe(0)
+
+    const appTrace = await fs.readJSON(
+      join(appDir, '.next/server/pages/_app.js.nft.json')
+    )
+    const indexTrace = await fs.readJSON(
+      join(appDir, '.next/server/pages/index.js.nft.json')
+    )
+
+    expect(appTrace.files.some((file) => file.endsWith('hello.json'))).toBe(
+      true
+    )
+    expect(
+      indexTrace.files.some((file) => file.endsWith('hello.json'))
+    ).toBeFalsy()
+  })
+})