Add entrypoint tracing

packages/next/build/webpack-config.ts

@@ -38,6 +38,7 @@ import BuildStatsPlugin from './webpack/plugins/build-stats-plugin'
 import ChunkNamesPlugin from './webpack/plugins/chunk-names-plugin'
 import { JsConfigPathsPlugin } from './webpack/plugins/jsconfig-paths-plugin'
 import { DropClientPage } from './webpack/plugins/next-drop-client-page-plugin'
+import { TraceEntryPointsPlugin } from './webpack/plugins/next-trace-entrypoints-plugin'
 import NextJsSsrImportPlugin from './webpack/plugins/nextjs-ssr-import'
 import NextJsSSRModuleCachePlugin from './webpack/plugins/nextjs-ssr-module-cache'
 import PagesManifestPlugin from './webpack/plugins/pages-manifest-plugin'
@@ -1163,6 +1164,10 @@ export default async function getBaseWebpackConfig(
           pagesDir,
         }),
       !isServer && new DropClientPage(),
+      !isLikeServerless &&
+        isServer &&
+        !dev &&
+        new TraceEntryPointsPlugin({ appDir: dir }),
       // Moment.js is an extremely popular library that bundles large locale files
       // by default due to how Webpack interprets its code. This is a practical
       // solution that requires the user to opt into importing specific locales.

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

@@ -0,0 +1,238 @@
+import nodePath from 'path'
+import { nodeFileTrace } from 'next/dist/compiled/@vercel/nft'
+import {
+  webpack,
+  isWebpack5,
+  sources,
+} from 'next/dist/compiled/webpack/webpack'
+import { TRACE_OUTPUT_VERSION } from '../../../next-server/lib/constants'
+
+const PLUGIN_NAME = 'TraceEntryPointsPlugin'
+const TRACE_IGNORES = [
+  '**/*/node_modules/react/**/*.development.js',
+  '**/*/node_modules/react-dom/**/*.development.js',
+]
+
+function getChunkGroupFromBlock(
+  compilation: any,
+  block: any
+): webpack.compilation.ChunkGroup {
+  if (isWebpack5) {
+    return compilation.chunkGraph.getBlockChunkGroup(block)
+  }
+
+  return block.chunkGroup
+}
+
+function getModuleFromDependency(
+  compilation: any,
+  dep: any
+): webpack.Module & { resource?: string } {
+  if (isWebpack5) {
+    return compilation.moduleGraph.getModule(dep)
+  }
+
+  return dep.module
+}
+
+export class TraceEntryPointsPlugin implements webpack.Plugin {
+  private appDir: string
+  private entryTraces: Map<string, string[]>
+  private entryModMap: Map<string, any>
+  private entryNameMap: Map<string, string>
+
+  constructor({ appDir }: { appDir: string }) {
+    this.appDir = appDir
+    this.entryTraces = new Map()
+    this.entryModMap = new Map()
+    this.entryNameMap = new Map()
+  }
+
+  createTraceAssets(compilation: any, assets: any) {
+    const namePathMap = new Map<string, string>()
+
+    this.entryNameMap.forEach((value, key) => {
+      namePathMap.set(value, key)
+    })
+
+    for (const entrypoint of compilation.entrypoints.values()) {
+      const entryFiles = new Set<string>()
+      const entryMod = this.entryModMap.get(namePathMap.get(entrypoint.name)!)
+
+      entrypoint.getFiles().forEach((file: string) => {
+        if (!file.endsWith(entrypoint.name + '.js')) {
+          entryFiles.add(nodePath.join(compilation.outputOptions.path, file))
+        }
+      })
+
+      for (const block of entryMod.blocks) {
+        const chunkGroup = getChunkGroupFromBlock(compilation, block)
+
+        if (!chunkGroup) {
+          continue
+        }
+
+        for (const chunk of (chunkGroup as any).chunks || []) {
+          chunk.files?.forEach((file: string) => {
+            entryFiles.add(nodePath.join(compilation.outputOptions.path, file))
+          })
+        }
+      }
+
+      assets[
+        `${isWebpack5 ? '../' : ''}${entrypoint.name}.nft.json`
+      ] = new sources.RawSource(
+        JSON.stringify({
+          version: TRACE_OUTPUT_VERSION,
+          files: [...entryFiles, ...this.entryTraces.get(entrypoint.name)!],
+        })
+      )
+    }
+  }
+
+  apply(compiler: webpack.Compiler) {
+    if (isWebpack5) {
+      compiler.hooks.make.tap('NextJsPagesManifest', (compilation) => {
+        // @ts-ignore TODO: Remove ignore when webpack 5 is stable
+        compilation.hooks.processAssets.tap(
+          {
+            name: 'NextJsPagesManifest',
+            // @ts-ignore TODO: Remove ignore when webpack 5 is stable
+            stage: webpack.Compilation.PROCESS_ASSETS_STAGE_ADDITIONS,
+          },
+          (assets: any) => {
+            this.createTraceAssets(compilation, assets)
+          }
+        )
+      })
+    } else {
+      compiler.hooks.emit.tap('NextJsPagesManifest', (compilation: any) => {
+        this.createTraceAssets(compilation, compilation.assets)
+      })
+    }
+
+    compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
+      compilation.hooks.finishModules.tapAsync(
+        PLUGIN_NAME,
+        async (_stats: any, callback: 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 (entryMod.resource) {
+                  this.entryNameMap.set(entryMod.resource, name)
+                  this.entryModMap.set(entryMod.resource, entryMod)
+                }
+              }
+            })
+
+            const readFile = (path: string) => {
+              const mod = depModMap.get(path) || this.entryModMap.get(path)
+
+              // map the transpiled source when available to avoid
+              // parse errors in node-file-trace
+              if (mod?._source?._valueAsBuffer) {
+                return mod._source._valueAsBuffer
+              }
+
+              try {
+                return compilation.inputFileSystem.readFileSync(path)
+              } catch (e) {
+                if (e.code === 'ENOENT' || e.code === 'EISDIR') {
+                  return null
+                }
+                throw e
+              }
+            }
+            const readlink = (path: string) => {
+              try {
+                return compilation.inputFileSystem.readlinkSync(path)
+              } catch (e) {
+                if (
+                  e.code !== 'EINVAL' &&
+                  e.code !== 'ENOENT' &&
+                  e.code !== 'UNKNOWN'
+                ) {
+                  throw e
+                }
+                return null
+              }
+            }
+            const stat = (path: string) => {
+              try {
+                return compilation.inputFileSystem.statSync(path)
+              } catch (e) {
+                if (e.code === 'ENOENT') {
+                  return null
+                }
+                throw e
+              }
+            }
+
+            const nftCache = {}
+            const entryPaths = Array.from(this.entryModMap.keys())
+
+            for (const entry of entryPaths) {
+              depModMap.clear()
+              const entryMod = this.entryModMap.get(entry)
+              const cachedTraces = entryMod.buildInfo?.cachedNextEntryTrace
+
+              if (isWebpack5 && cachedTraces) {
+                this.entryTraces.set(
+                  this.entryNameMap.get(entry)!,
+                  cachedTraces
+                )
+                continue
+              }
+
+              for (const dep of entryMod.dependencies) {
+                const depMod = getModuleFromDependency(compilation, dep)
+
+                if (depMod?.resource) {
+                  depModMap.set(depMod.resource, depMod)
+                }
+              }
+
+              const toTrace: string[] = [entry, ...depModMap.keys()]
+
+              const root = nodePath.parse(process.cwd()).root
+              const result = await nodeFileTrace(toTrace, {
+                base: root,
+                cache: nftCache,
+                processCwd: this.appDir,
+                readFile,
+                readlink,
+                stat,
+                ignore: TRACE_IGNORES,
+              })
+
+              const tracedDeps: string[] = []
+
+              for (const file of result.fileList) {
+                if (result.reasons[file].type === 'initial') {
+                  continue
+                }
+                tracedDeps.push(nodePath.join(root, file))
+              }
+
+              entryMod.buildInfo.cachedNextEntryTrace = tracedDeps
+              this.entryTraces.set(this.entryNameMap.get(entry)!, tracedDeps)
+            }
+
+            callback()
+          } catch (err) {
+            callback(err)
+          }
+        }
+      )
+    })
+  }
+}

packages/next/compiled/@vercel/nft/LICENSE

@@ -0,0 +1,7 @@
+Copyright 2019 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

packages/next/compiled/@vercel/nft/package.json

@@ -0,0 +1 @@
+{"name":"@vercel/nft","main":"index.js","license":"MIT"}