Exclude next-js condition from middleware, proxy, and instrumentation

These scopes aren't fully Next.js environments and can't access many Next.js APIs. In the future this might change but for now we will exclude the `next-js` condition when bundling for these entrypoints so that 3rd parties that target Next.js can do so with the expectation that regardless of what environment they are running in the full suite of Next.js libraries they support will work.

Author: gnoff

crates/next-core/src/next_edge/context.rs

@@ -153,9 +153,9 @@ pub async fn get_edge_resolve_options_context(
         custom_conditions.push(rcstr!("react-server"));
     };
 
-    if *next_config.enable_cache_components().await? {
-        custom_conditions.push(rcstr!("next-js"));
-    };
+    // Edge runtime is disabled for projects with Cache Components enabled except for Middleware
+    // but Middleware doesn't have all Next.js APIs so we omit the "next-js" condition for all edge
+    // entrypoints
 
     let resolve_options_context = ResolveOptionsContext {
         enable_node_modules: Some(project_path.root().owned().await?),

crates/next-core/src/next_server/context.rs

@@ -214,7 +214,10 @@ pub async fn get_server_resolve_options_context(
         custom_conditions.push(rcstr!("react-server"));
     };
 
-    if *next_config.enable_cache_components().await? {
+    if *next_config.enable_cache_components().await?
+        // Middleware shouldn't use the "next-js" condition because it doesn't have all Next.js APIs available
+        && !matches!(ty, ServerContextType::Middleware { .. } |  ServerContextType::Instrumentation { .. })
+    {
         custom_conditions.push(rcstr!("next-js"));
     };
 

packages/next/src/build/webpack-config.ts

@@ -687,7 +687,6 @@ export default async function getBaseWebpackConfig(
     : distDir
 
   const conditionNames = [
-    ...(config.cacheComponents === true ? ['next-js'] : []),
     ...(isEdgeServer ? [edgeConditionName] : []),
     // inherits Webpack's default conditions
     '...',
@@ -1389,6 +1388,17 @@ export default async function getBaseWebpackConfig(
     },
     module: {
       rules: [
+        {
+          issuerLayer: {
+            not: [WEBPACK_LAYERS.middleware, WEBPACK_LAYERS.instrument],
+          },
+          resolve: {
+            conditionNames: [
+              config.cacheComponents ? 'next-js' : '',
+              '...',
+            ].filter(Boolean) as string[],
+          },
+        },
         // Alias server-only and client-only to proper exports based on bundling layers
         {
           issuerLayer: {