build(shared): nest internal build chunks under _chunks/ (#8717)

Author: jacekradko

.changeset/shared-nest-internal-chunks.md

@@ -0,0 +1,5 @@
+---
+'@clerk/shared': patch
+---
+
+Nest rolldown's shared build chunks under `dist/runtime/_chunks/` instead of emitting them flat next to the entry points. The package exposes `"./*"`, which resolves to `dist/runtime/*`, so the content-hashed internal chunks were being picked up by API-diff tooling whenever a chunk hash shifted. Entry and type resolution are unchanged; the chunks are still referenced by relative path, and external `./_chunks/*` package subpaths are blocked.

packages/shared/package.json

@@ -30,6 +30,7 @@
         "default": "./dist/runtime/internal/clerk-js/*.js"
       }
     },
+    "./_chunks/*": null,
     "./*": {
       "import": {
         "types": "./dist/runtime/*.d.mts",

packages/shared/tsdown.config.mts

@@ -55,6 +55,23 @@ export default defineConfig(({ watch, env }) => {
       ],
       outDir: './dist/runtime',
       unbundle: false,
+      // Route rolldown's shared chunks into a nested `_chunks/` directory. The
+      // package's `"./*"` wildcard export resolves to `dist/runtime/*`, and
+      // break-check expands that surface with a single-segment `*`, so
+      // content-hashed internal chunks sitting flat in `dist/runtime` get
+      // enumerated as phantom public subpaths. Nesting them one level down keeps
+      // them out of that API-snapshot expansion; package subpath imports are
+      // blocked separately by the `./_chunks/*` null export.
+      outputOptions: options => {
+        const { chunkFileNames } = options;
+        return {
+          ...options,
+          chunkFileNames:
+            typeof chunkFileNames === 'function'
+              ? info => `_chunks/${chunkFileNames(info)}`
+              : `_chunks/${chunkFileNames ?? '[name]-[hash].js'}`,
+        };
+      },
     },
   ];
 });