Remove static analysis of process.env (#50260)

Since there is no longer a limitation that requires us to static analyze `process.env`, this PR removes it from the build process and updates the corresponding documentation.
vercel · May 24, 2023 · aa91de5 · aa91de5
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diff --git a/docs/api-reference/edge-runtime.md b/docs/api-reference/edge-runtime.md
@@ -130,15 +130,6 @@ The Edge Runtime supports the following web standard APIs:
 
 You can use `process.env` to access [Environment Variables](/docs/basic-features/environment-variables.md) for both `next dev` and `next build`.
 
-Running `console.log` on `process.env` **will not** show all your Environment Variables. You have to access the variables directly as shown below:
-
-```javascript
-console.log(process.env)
-// { NEXT_RUNTIME: 'edge' }
-console.log(process.env.TEST_VARIABLE)
-// value
-```
-
 ## Compatible Node.js Modules
 
 The following modules can be imported with and without the `node:` prefix when using the `import` statement:

diff --git a/docs/basic-features/environment-variables.md b/docs/basic-features/environment-variables.md
@@ -44,10 +44,6 @@ export async function getStaticProps() {
 }
 ```
 
-> **Note**: In order to keep server-only secrets safe, environment variables are evaluated at build time, so only environment variables _actually_ used will be included. This means that `process.env` is not a standard JavaScript object, so you’re not able to
-> use [object destructuring](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment).
-> Environment variables must be referenced as e.g. `process.env.PUBLISHABLE_KEY`, _not_ `const { PUBLISHABLE_KEY } = process.env`.
-
 > **Note**: Next.js will automatically expand variables (`$VAR`) inside of your `.env*` files.
 > This allows you to reference other secrets, like so:
 >

diff --git a/packages/next/src/build/utils.ts b/packages/next/src/build/utils.ts
@@ -1389,7 +1389,6 @@ export async function isPageStatic({
       if (pathIsEdgeRuntime) {
         const runtime = await getRuntimeContext({
           paths: edgeInfo.files.map((file: string) => path.join(distDir, file)),
-          env: edgeInfo.env,
           edgeFunctionEntry: {
             ...edgeInfo,
             wasm: (edgeInfo.wasm ?? []).map((binding: AssetBinding) => ({

diff --git a/packages/next/src/build/webpack/loaders/get-module-build-info.ts b/packages/next/src/build/webpack/loaders/get-module-build-info.ts
@@ -33,7 +33,6 @@ export function getModuleBuildInfo(webpackModule: webpack.Module) {
     nextEdgeMiddleware?: EdgeMiddlewareMeta
     nextEdgeApiFunction?: EdgeMiddlewareMeta
     nextEdgeSSR?: EdgeSSRMeta
-    nextUsedEnvVars?: Set<string>
     nextWasmMiddlewareBinding?: AssetBinding
     nextAssetMiddlewareBinding?: AssetBinding
     usingIndirectEval?: boolean | Set<string>

diff --git a/packages/next/src/build/webpack/plugins/middleware-plugin.ts b/packages/next/src/build/webpack/plugins/middleware-plugin.ts
@@ -34,7 +34,6 @@ import { INSTRUMENTATION_HOOK_FILENAME } from '../../../lib/constants'
 import { NextBuildContext } from '../../build-context'
 
 export interface EdgeFunctionDefinition {
-  env: string[]
   files: string[]
   name: string
   page: string
@@ -55,7 +54,6 @@ interface EntryMetadata {
   edgeMiddleware?: EdgeMiddlewareMeta
   edgeApiFunction?: EdgeMiddlewareMeta
   edgeSSR?: EdgeSSRMeta
-  env: Set<string>
   wasmBindings: Map<string, string>
   assetBindings: Map<string, string>
   regions?: string[] | string
@@ -188,7 +186,6 @@ function getCreateAssets(params: {
       ]
 
       const edgeFunctionDefinition: EdgeFunctionDefinition = {
-        env: Array.from(metadata.env),
         files: getEntryFiles(entrypoint.getFiles(), metadata, opts),
         name: entrypoint.name,
         page: page,
@@ -248,17 +245,6 @@ function isInMiddlewareLayer(parser: webpack.javascript.JavascriptParser) {
   return parser.state.module?.layer === 'middleware'
 }
 
-function isProcessEnvMemberExpression(memberExpression: any): boolean {
-  return (
-    memberExpression.object?.type === 'Identifier' &&
-    memberExpression.object.name === 'process' &&
-    ((memberExpression.property?.type === 'Literal' &&
-      memberExpression.property.value === 'env') ||
-      (memberExpression.property?.type === 'Identifier' &&
-        memberExpression.property.name === 'env'))
-  )
-}
-
 function isNodeJsModule(moduleName: string) {
   return require('module').builtinModules.includes(moduleName)
 }
@@ -461,32 +447,6 @@ function getCodeAnalyzer(params: {
       }
     }
 
-    /**
-     * Declares an environment variable that is being used in this module
-     * through this static analysis.
-     */
-    const addUsedEnvVar = (envVarName: string) => {
-      const buildInfo = getModuleBuildInfo(parser.state.module)
-      if (buildInfo.nextUsedEnvVars === undefined) {
-        buildInfo.nextUsedEnvVars = new Set()
-      }
-
-      buildInfo.nextUsedEnvVars.add(envVarName)
-    }
-
-    /**
-     * A handler for calls to `process.env` where we identify the name of the
-     * ENV variable being assigned and store it in the module info.
-     */
-    const handleCallMemberChain = (_: unknown, members: string[]) => {
-      if (members.length >= 2 && members[0] === 'env') {
-        addUsedEnvVar(members[1])
-        if (!isInMiddlewareLayer(parser)) {
-          return true
-        }
-      }
-    }
-
     /**
      * Handler to store original source location of static and dynamic imports into module's buildInfo.
      */
@@ -541,41 +501,9 @@ Learn More: https://nextjs.org/docs/messages/node-module-in-edge-runtime`,
         .tap(NAME, handleWrapWasmInstantiateExpression)
     }
 
-    hooks.callMemberChain.for('process').tap(NAME, handleCallMemberChain)
-    hooks.expressionMemberChain.for('process').tap(NAME, handleCallMemberChain)
     hooks.importCall.tap(NAME, handleImport)
     hooks.import.tap(NAME, handleImport)
 
-    /**
-     * Support static analyzing environment variables through
-     * destructuring `process.env` or `process["env"]`:
-     *
-     * const { MY_ENV, "MY-ENV": myEnv } = process.env
-     *         ^^^^^^   ^^^^^^
-     */
-    hooks.declarator.tap(NAME, (declarator) => {
-      if (
-        declarator.init?.type === 'MemberExpression' &&
-        isProcessEnvMemberExpression(declarator.init) &&
-        declarator.id?.type === 'ObjectPattern'
-      ) {
-        for (const property of declarator.id.properties) {
-          if (property.type === 'RestElement') continue
-          if (
-            property.key.type === 'Literal' &&
-            typeof property.key.value === 'string'
-          ) {
-            addUsedEnvVar(property.key.value)
-          } else if (property.key.type === 'Identifier') {
-            addUsedEnvVar(property.key.name)
-          }
-        }
-
-        if (!isInMiddlewareLayer(parser)) {
-          return true
-        }
-      }
-    })
     if (!dev) {
       // do not issue compilation warning on dev: invoking code will provide details
       registerUnsupportedApiHooks(parser, compilation)
@@ -653,7 +581,6 @@ function getExtractMetadata(params: {
       entry.includeDependencies.forEach(addEntriesFromDependency)
 
       const entryMetadata: EntryMetadata = {
-        env: new Set<string>(),
         wasmBindings: new Map(),
         assetBindings: new Map(),
       }
@@ -760,16 +687,6 @@ function getExtractMetadata(params: {
           entryMetadata.edgeApiFunction = buildInfo.nextEdgeApiFunction
         }
 
-        /**
-         * If there are env vars found in the module, append them to the set
-         * of env vars for the entry.
-         */
-        if (buildInfo?.nextUsedEnvVars !== undefined) {
-          for (const envName of buildInfo.nextUsedEnvVars) {
-            entryMetadata.env.add(envName)
-          }
-        }
-
         /**
          * If the module is a WASM module we read the binding information and
          * append it to the entry wasm bindings.

diff --git a/packages/next/src/server/lib/route-resolver.ts b/packages/next/src/server/lib/route-resolver.ts
@@ -165,7 +165,6 @@ export async function makeResolver(
           return {
             name: 'middleware',
             paths: middleware.files.map((file) => join(process.cwd(), file)),
-            env: Object.keys(process.env),
             wasm: [],
             assets: [],
           }

diff --git a/packages/next/src/server/next-server.ts b/packages/next/src/server/next-server.ts
@@ -2183,7 +2183,6 @@ export default class NextNodeServer extends BaseServer {
   }): {
     name: string
     paths: string[]
-    env: string[]
     wasm: { filePath: string; name: string }[]
     assets: { filePath: string; name: string }[]
   } | null {
@@ -2214,7 +2213,6 @@ export default class NextNodeServer extends BaseServer {
     return {
       name: pageInfo.name,
       paths: pageInfo.files.map((file) => join(this.distDir, file)),
-      env: pageInfo.env ?? [],
       wasm: (pageInfo.wasm ?? []).map((binding) => ({
         ...binding,
         filePath: join(this.distDir, binding.filePath),
@@ -2322,7 +2320,6 @@ export default class NextNodeServer extends BaseServer {
       distDir: this.distDir,
       name: middlewareInfo.name,
       paths: middlewareInfo.paths,
-      env: middlewareInfo.env,
       edgeFunctionEntry: middlewareInfo,
       request: {
         headers: params.request.headers,
@@ -2825,7 +2822,6 @@ export default class NextNodeServer extends BaseServer {
       distDir: this.distDir,
       name: edgeInfo.name,
       paths: edgeInfo.paths,
-      env: edgeInfo.env,
       edgeFunctionEntry: edgeInfo,
       request: {
         headers: params.req.headers,

diff --git a/packages/next/src/server/web/sandbox/context.ts b/packages/next/src/server/web/sandbox/context.ts
@@ -91,10 +91,8 @@ async function loadWasm(
   return modules
 }
 
-function buildEnvironmentVariablesFrom(
-  keys: string[]
-): Record<string, string | undefined> {
-  const pairs = keys.map((key) => [key, process.env[key]])
+function buildEnvironmentVariablesFrom(): Record<string, string | undefined> {
+  const pairs = Object.keys(process.env).map((key) => [key, process.env[key]])
   const env = Object.fromEntries(pairs)
   env.NEXT_RUNTIME = 'edge'
   return env
@@ -108,10 +106,8 @@ Learn more: https://nextjs.org/docs/api-reference/edge-runtime`)
   throw error
 }
 
-function createProcessPolyfill(options: Pick<ModuleContextOptions, 'env'>) {
-  const env = buildEnvironmentVariablesFrom(options.env)
-
-  const processPolyfill = { env }
+function createProcessPolyfill() {
+  const processPolyfill = { env: buildEnvironmentVariablesFrom() }
   const overridenValue: Record<string, any> = {}
   for (const key of Object.keys(process)) {
     if (key === 'env') continue
@@ -236,7 +232,7 @@ async function createModuleContext(options: ModuleContextOptions) {
         : undefined,
     extend: (context) => {
       context.WebSocket = require('next/dist/compiled/ws').WebSocket
-      context.process = createProcessPolyfill(options)
+      context.process = createProcessPolyfill()
 
       Object.defineProperty(context, 'require', {
         enumerable: false,
@@ -416,7 +412,6 @@ interface ModuleContextOptions {
   moduleName: string
   onWarning: (warn: Error) => void
   useCache: boolean
-  env: string[]
   distDir: string
   edgeFunctionEntry: Pick<EdgeFunctionDefinition, 'assets' | 'wasm'>
 }

diff --git a/packages/next/src/server/web/sandbox/sandbox.ts b/packages/next/src/server/web/sandbox/sandbox.ts
@@ -15,7 +15,6 @@ const FORBIDDEN_HEADERS = [
 
 type RunnerFn = (params: {
   name: string
-  env: string[]
   onWarning?: (warn: Error) => void
   paths: string[]
   request: NodejsRequestData
@@ -49,7 +48,6 @@ export const getRuntimeContext = async (params: {
   name: string
   onWarning?: any
   useCache: boolean
-  env: string[]
   edgeFunctionEntry: any
   distDir: string
   paths: string[]
@@ -59,7 +57,6 @@ export const getRuntimeContext = async (params: {
     moduleName: params.name,
     onWarning: params.onWarning ?? (() => {}),
     useCache: params.useCache !== false,
-    env: params.env,
     edgeFunctionEntry: params.edgeFunctionEntry,
     distDir: params.distDir,
   })

diff --git a/test/e2e/middleware-general/app/middleware.js b/test/e2e/middleware-general/app/middleware.js
@@ -116,22 +116,6 @@ export async function middleware(request) {
   }
 
   if (url.pathname === '/global') {
-    // The next line is required to allow to find the env variable
-    // eslint-disable-next-line no-unused-expressions
-    process.env.MIDDLEWARE_TEST
-
-    // The next line is required to allow to find the env variable
-    // eslint-disable-next-line no-unused-expressions
-    const { ANOTHER_MIDDLEWARE_TEST } = process.env
-    if (!ANOTHER_MIDDLEWARE_TEST) {
-      console.log('missing ANOTHER_MIDDLEWARE_TEST')
-    }
-
-    const { STRING_ENV_VAR: stringEnvVar } = process['env']
-    if (!stringEnvVar) {
-      console.log('missing STRING_ENV_VAR')
-    }
-
     return serializeData(JSON.stringify({ process: { env: process.env } }))
   }
 

diff --git a/test/e2e/middleware-general/test/index.test.ts b/test/e2e/middleware-general/test/index.test.ts
@@ -138,11 +138,6 @@ describe('Middleware Runtime', () => {
         )
         expect(manifest.middleware).toEqual({
           '/': {
-            env: expect.arrayContaining([
-              'MIDDLEWARE_TEST',
-              'ANOTHER_MIDDLEWARE_TEST',
-              'STRING_ENV_VAR',
-            ]),
             files: expect.arrayContaining([
               'server/edge-runtime-webpack.js',
               'server/middleware.js',
@@ -481,7 +476,7 @@ describe('Middleware Runtime', () => {
       })
     }
 
-    it('should contain process polyfill', async () => {
+    it('allows to access env variables', async () => {
       const res = await fetchViaHTTP(next.url, `/global`)
       const json = readMiddlewareJSON(res)
 

diff --git a/test/e2e/middleware-trailing-slash/test/index.test.ts b/test/e2e/middleware-trailing-slash/test/index.test.ts
@@ -113,7 +113,6 @@ describe('Middleware Runtime trailing slash', () => {
           '/': {
             files: ['server/edge-runtime-webpack.js', 'server/middleware.js'],
             name: 'middleware',
-            env: expect.arrayContaining([]),
             page: '/',
             matchers: [{ regexp: '^/.*$', originalSource: '/:path*' }],
             wasm: [],

diff --git a/test/e2e/switchable-runtime/index.test.ts b/test/e2e/switchable-runtime/index.test.ts
@@ -187,7 +187,6 @@ describe('Switchable runtime', () => {
           expect(manifest).toMatchObject({
             functions: {
               '/api/hello': {
-                env: expect.arrayContaining([]),
                 files: [
                   'server/edge-runtime-webpack.js',
                   'server/pages/api/hello.js',
@@ -200,7 +199,6 @@ describe('Switchable runtime', () => {
                 wasm: [],
               },
               '/api/edge': {
-                env: expect.arrayContaining([]),
                 files: [
                   'server/edge-runtime-webpack.js',
                   'server/pages/api/edge.js',
@@ -623,7 +621,6 @@ describe('Switchable runtime', () => {
           expect(manifest).toMatchObject({
             functions: {
               '/api/hello': {
-                env: expect.arrayContaining([]),
                 files: [
                   'server/edge-runtime-webpack.js',
                   'server/pages/api/hello.js',
@@ -636,7 +633,6 @@ describe('Switchable runtime', () => {
                 wasm: [],
               },
               '/api/edge': {
-                env: expect.arrayContaining([]),
                 files: [
                   'server/edge-runtime-webpack.js',
                   'server/pages/api/edge.js',