fix: check NEXT_DISABLE_NETLIFY_EDGE value rather than if truthy (#1603)

* fix: check NEXT_DISABLE_NETLIFY_EDGE value rather than if truthy

* fix: convert to string compare

* fix: allow unset var behavior to remain

* chore(docs): update middleware docs

* fix: update logic

Co-authored-by: Matt Kane <[email protected]>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: 3 people

README.md

@@ -16,7 +16,7 @@ commands separately will not work, because the Next.js Runtime will not generate
 If you use [`next/image`](https://nextjs.org/docs/basic-features/image-optimization), your images will be automatically
 optimized at runtime, ensuring that they are served at the best size and format. The image will be processed on the
 first request which means it may take longer to load, but the generated image is then cached at the edge and served as a
-static file to future visitors. By default, Next will deliver WebP images if the browser supports it. WebP is a new
+static file to future visitors. By default, Next.js will deliver WebP images if the browser supports it. WebP is a new
 image format with wide browser support that will usually generate smaller files than png or jpg. You can additionally
 enable the AVIF format, which is often even smaller in filesize than WebP. The drawback is that with particularly large
 images AVIF may take too long to generate, meaning the function times-out. You can configure
@@ -48,6 +48,8 @@ Next.js Middleware works out of the box on Netlify. By default, middleware runs
 support for running Middleware at the origin, set the environment variable `NEXT_DISABLE_NETLIFY_EDGE` to `true`. Be
 aware that this will result in slower performance, as all pages that match middleware must use SSR.
 
+For more details on Next.js Middleware with Netlify, see the [middleware docs](https://github.com/netlify/next-runtime/blob/main/docs/middleware.md).
+
 ## Monorepos
 
 If you are using a monorepo you will need to change `publish` to point to the full path to the built `.next` directory,
@@ -111,7 +113,7 @@ If you previously set these values, they're no longer needed and should be remov
 - `external_node_modules` in `netlify.toml`
 - The environment variable `NEXT_USE_NETLIFY_EDGE` can be removed as this is now the default
 
-The `serverless` and `experimental-serverless-trace` targets are deprecated in Next 12, and all builds with this Next
+The `serverless` and `experimental-serverless-trace` targets are deprecated in Next.js 12, and all builds with this Next.js
 Runtime will now use the default `server` target. If you previously set the target in your `next.config.js`, you should
 remove it.
 

docs/middleware.md

@@ -1,19 +1,15 @@
-# Using Next 12 middleware on Netlify
+# Using Next.js 12 middleware on Netlify
 
-Next 12 introduces a new feature called [Middleware](https://nextjs.org/docs/middleware), in which functions run before
+Next.js 12 introduces a new feature called [Middleware](https://nextjs.org/docs/middleware), in which functions run before
 a request has finished processing. Middleware can be used to modify the request or replace the response. For example, it
 can change headers, rewrite the request path, or return a different response entirely.
 
 Next.js Middleware can run either in an edge function (highly recommended for version 12.2+ as ISR will not work
 otherwise) or at the origin. On Netlify, Middleware runs at the origin as part of the normal Next.js server.
 
-If you'd like to run Middleware at the edge, set the environment variable `NEXT_USE_NETLIFY_EDGE` to `true`.
+## How to deploy Next.js 12 middleware
 
-## How to deploy Next 12 middleware
-
-Next 12 Middleware works out of the box with Netlify, and most functions will work unchanged. See
-[the middleware docs](https://nextjs.org/docs/middleware) for details of how to create them. There are however a few
-workarounds that are currently required for some features during the beta period:
+Next.js 12 Middleware works out of the box with Netlify, and most functions will work unchanged. By default, middleware runs using Netlify Edge Functions. For legacy support for running Middleware at the origin, set the environment variable `NEXT_DISABLE_NETLIFY_EDGE` to `true`. Be aware that this will result in slower performance, as all pages that match middleware must use SSR. See [the middleware docs](https://nextjs.org/docs/middleware) for details of how to create Next.js middleware. There are however a few workarounds that are currently required for some features during the beta period:
 
 ### `geo`
 

docs/release-notes/v4.md

@@ -9,7 +9,7 @@ stability.
   [incremental static regeneration (ISR)](https://github.com/netlify/next-runtime/blob/main/docs/isr.md).
 - Full support for
   [Next.js rewrites, redirects and headers](https://github.com/netlify/next-runtime/blob/main/docs/redirects-rewrites.md).
-- Beta support for [Next 12 Middleware](https://github.com/netlify/next-runtime/blob/main/docs/middleware.md)
+- Beta support for [Next.js 12 Middleware](https://github.com/netlify/next-runtime/blob/main/docs/middleware.md)
 - Faster builds and deploys. Instead of generating one function per route, there are just three functions per site and a
   much smaller list of rewrites.
 - Full support for Netlify's new [persistent On-Demand Builders](https://ntl.fyi/odb). Return `fallback: "blocking"`
@@ -20,7 +20,7 @@ stability.
 - Simplified configuration. You no longer need to set any Netlify-specific configuration options. For example, in a
   monorepo all you need to do is set `publish` to point to your `.next` directory and you can build the site in any way
   you like.
-- Removes requirement for the `target` to be set to `serverless`, which is deprecated in Next 12.
+- Removes requirement for the `target` to be set to `serverless`, which is deprecated in Next.js 12.
 - Bundling now uses Next.js's own node-file-trace, giving more predictable results and smaller uploads.
 
 ## Migration guide
@@ -45,6 +45,6 @@ If you currently use redirects or rewrites on your site, see
 information on changes to how they are handled in this version. If you currently have `_redirects` or `_headers` files
 in the root of your site, these will need to be moved into "public".
 
-If you want to use Next 12's beta Middleware feature, this will mostly work as expected but please
+If you want to use Next.js 12's beta Middleware feature, this will mostly work as expected but please
 [read the docs on some caveats and workarounds](https://github.com/netlify/next-runtime/blob/main/docs/middleware.md)
 that are currently needed.

packages/runtime/src/helpers/edge.ts

@@ -214,7 +214,7 @@ export const writeEdgeFunctions = async (netlifyConfig: NetlifyConfig) => {
       path: '/_next/image*',
     })
   }
-  if (!process.env.NEXT_DISABLE_NETLIFY_EDGE) {
+  if (process.env.NEXT_DISABLE_NETLIFY_EDGE !== 'true' && process.env.NEXT_DISABLE_NETLIFY_EDGE !== '1') {
     const middlewareManifest = await loadMiddlewareManifest(netlifyConfig)
     if (!middlewareManifest) {
       console.error("Couldn't find the middleware manifest")

packages/runtime/src/helpers/files.ts

@@ -60,7 +60,7 @@ export const matchesRewrite = (file: string, rewrites: Rewrites): boolean => {
 }
 
 export const getMiddleware = async (publish: string): Promise<Array<string>> => {
-  if (!process.env.NEXT_DISABLE_NETLIFY_EDGE) {
+  if (process.env.NEXT_DISABLE_NETLIFY_EDGE !== 'true' && process.env.NEXT_DISABLE_NETLIFY_EDGE !== '1') {
     return []
   }
   const manifestPath = join(publish, 'server', 'middleware-manifest.json')
@@ -346,19 +346,19 @@ const baseServerReplacements: Array<[string, string]> = [
 const nextServerReplacements: Array<[string, string]> = [
   [
     `getMiddlewareManifest() {\n        if (this.minimalMode) return null;`,
-    `getMiddlewareManifest() {\n        if (this.minimalMode || !process.env.NEXT_DISABLE_NETLIFY_EDGE) return null;`,
+    `getMiddlewareManifest() {\n        if (this.minimalMode || (process.env.NEXT_DISABLE_NETLIFY_EDGE !== 'true' && process.env.NEXT_DISABLE_NETLIFY_EDGE !== '1')) return null;`,
   ],
   [
     `generateCatchAllMiddlewareRoute(devReady) {\n        if (this.minimalMode) return []`,
-    `generateCatchAllMiddlewareRoute(devReady) {\n        if (this.minimalMode || !process.env.NEXT_DISABLE_NETLIFY_EDGE) return [];`,
+    `generateCatchAllMiddlewareRoute(devReady) {\n        if (this.minimalMode || (process.env.NEXT_DISABLE_NETLIFY_EDGE !== 'true' && process.env.NEXT_DISABLE_NETLIFY_EDGE !== '1')) return [];`,
   ],
   [
     `generateCatchAllMiddlewareRoute() {\n        if (this.minimalMode) return undefined;`,
-    `generateCatchAllMiddlewareRoute() {\n        if (this.minimalMode || !process.env.NEXT_DISABLE_NETLIFY_EDGE) return undefined;`,
+    `generateCatchAllMiddlewareRoute() {\n        if (this.minimalMode || (process.env.NEXT_DISABLE_NETLIFY_EDGE !== 'true' && process.env.NEXT_DISABLE_NETLIFY_EDGE !== '1')) return undefined;`,
   ],
   [
     `getMiddlewareManifest() {\n        if (this.minimalMode) {`,
-    `getMiddlewareManifest() {\n        if (!this.minimalMode && process.env.NEXT_DISABLE_NETLIFY_EDGE) {`,
+    `getMiddlewareManifest() {\n        if (!this.minimalMode && (process.env.NEXT_DISABLE_NETLIFY_EDGE === 'true' || process.env.NEXT_DISABLE_NETLIFY_EDGE === '1')) {`,
   ],
 ]
 

packages/runtime/src/index.ts

@@ -92,23 +92,23 @@ const plugin: NetlifyPlugin = {
 
     if (middlewareManifest?.functions && Object.keys(middlewareManifest.functions).length !== 0) {
       usingEdge = true
-      if (process.env.NEXT_DISABLE_NETLIFY_EDGE) {
+      if (process.env.NEXT_DISABLE_NETLIFY_EDGE === 'true' || process.env.NEXT_DISABLE_NETLIFY_EDGE === '1') {
         failBuild(outdent`
           You are using Next.js experimental edge runtime, but have set NEXT_DISABLE_NETLIFY_EDGE to true. This is not supported.
-          To use edge runtime, remove the env var ${bold`NEXT_DISABLE_NETLIFY_EDGE`}.
+          To use edge runtime, remove the env var ${bold`NEXT_DISABLE_NETLIFY_EDGE`} or set it to false.
         `)
       }
     }
 
     if (middlewareManifest?.middleware && Object.keys(middlewareManifest.middleware).length !== 0) {
       usingEdge = true
-      if (process.env.NEXT_DISABLE_NETLIFY_EDGE) {
+      if (process.env.NEXT_DISABLE_NETLIFY_EDGE === 'true' || process.env.NEXT_DISABLE_NETLIFY_EDGE === '1') {
         console.log(
           redBright(outdent`
             You are using Next.js Middleware without Netlify Edge Functions.
             This is deprecated because it negatively affects performance and will disable ISR and static rendering.
             It also disables advanced middleware features from @netlify/next
-            To get the best performance and use Netlify Edge Functions, remove the env var ${bold`NEXT_DISABLE_NETLIFY_EDGE`}.
+            To get the best performance and use Netlify Edge Functions, remove the env var ${bold`NEXT_DISABLE_NETLIFY_EDGE`} or set it to false.
           `),
         )
       }