Failed to resolve shim imports in sandbox environments

[eashish93]

vinext@0.0.46 ships two dist/server/*.js files that still import a shim via a relative path, which #1006 was meant to eliminate. The same vite:import-analysis failure that #1001 / #1006 fixed is back when running under @cloudflare/sandbox SDK.

Files still wrong in 0.0.46

// dist/server/app-page-boundary-render.js:3
// dist/server/app-page-route-wiring.js:3
import { LayoutSegmentProvider } from "../shims/layout-segment-context.js";

Should be:

import { LayoutSegmentProvider } from "vinext/shims/layout-segment-context";

…matching the pattern #1006 applied to the other 67 imports across 34 files.

Symptom

[plugin:vite:import-analysis] Failed to resolve import
"/workspace/node_modules/vinext/dist/shims/layout-segment-context.js"
from "virtual:vite-rsc/client-in-server-package-proxy/%2Fworkspace%2Fnode_modules%2Fvinext%2Fdist%2Fshims%2Flayout-segment-context.js"

Fires on first paint inside a @cloudflare/sandbox-managed container, every time.

Why plain vinext dev doesn't show it

Vite's optimizeDeps pre-bundles the shim and rewrites the absolute path import to ?v=<hash> form, masking it. Under the @cloudflare/sandbox SDK invocation path the optimizer cache misses, so the raw absolute path reaches import-analysis.normalizeUrl — which treats leading / as URL-relative-to-server-root, so /workspace/foo resolves to <root>/workspace/foo = /workspace/workspace/foo and fails.

Versions

vinext	0.0.46
@vitejs/plugin-rsc	^0.5.25
vite	8.0.10
@cloudflare/vite-plugin	^1.35.0
@cloudflare/sandbox	^0.9.2

Fix

Apply #1006's transform to those two files. Worth checking why the regression test added in #1006 didn't catch this in CI for 0.0.46.

Reproduce

Zip attached. README inside has the full mechanism walkthrough.

unzip vinext-shim-bug-repro.zip
cd vinext-shim-bug-repro/main
bun install
bun run dev
# open http://localhost:5200/ → click Start sandbox

vinext-shim-bug-repro.zip

[james-elicx]

The prerelease for the last commit on main is https://pkg.pr.new/vinext@a49be5c

Please can you try that?

[james-elicx]

Oh I see. The build that gets published is resolving the aliases and they're going back to relative paths.

[eashish93]

Trying now. Zip file though I've uploaded is using 0.0.46 (not .45) btw and now you can easily reproduce it.

[james-elicx]

Yes it won't make a difference, the imports are being transformed back to relative, which makes sense.

I think you should file an issue in the RSC plugin's repo as this sounds like a bug that will need fixing in how they deal with deps.

[eashish93]

I tried that pre-release and it's same, then I tried this patch:

#!/usr/bin/env bun
import { readdir, readFile, writeFile } from 'node:fs/promises';
import { join } from 'node:path';

const distRoot = process.argv[2];
if (!distRoot) {
  console.error('usage: patch-vinext-shims.ts <path-to-vinext/dist>');
  process.exit(1);
}

async function* walkJs(dir: string): AsyncGenerator<string> {
  for (const entry of await readdir(dir, { withFileTypes: true })) {
    const full = join(dir, entry.name);
    if (entry.isDirectory()) {
      if (entry.name === 'shims') continue;
      yield* walkJs(full);
    } else if (entry.isFile() && entry.name.endsWith('.js')) {
      yield full;
    }
  }
}

const importRe = /from "(?:\.\.\/)+shims\/([^"]+)\.js"|from "\.\/shims\/([^"]+)\.js"/g;
let totalRewrites = 0;
let touchedFiles = 0;

for await (const file of walkJs(distRoot)) {
  const original = await readFile(file, 'utf8');
  let count = 0;
  const rewritten = original.replace(importRe, (_m, a, b) => {
    count++;
    return `from "vinext/shims/${a ?? b}"`;
  });
  if (count > 0) {
    await writeFile(file, rewritten);
    touchedFiles++;
    totalRewrites += count;
    console.log(`  ${file.replace(distRoot, '')}: ${count}`);
  }
}

console.log(`\npatched ${totalRewrites} imports across ${touchedFiles} files`);

That fixes the issue for me, but then another vite plugin error occur which recently fixed here #1008 .

So I asked claude to give me a patch to apply. Here's the patch for this one:

#!/usr/bin/env bun
// Workaround for cloudflare/vinext#1008 / upstream vitejs/vite-plugin-react.
// `client-package-proxy`'s load handler crashes with
//   "Cannot read properties of undefined (reading 'exportNames')"
// when the rsc env hasn't yet transformed the package's shim file before the
// proxy URL is fetched. Patch the load handler to fall back to a wildcard
// re-export when the metadata isn't there yet.
//
// Idempotent — re-running it on already-patched files is a no-op.
import { readdir, readFile, writeFile } from 'node:fs/promises';
import { join } from 'node:path';

const root = process.argv[2];
if (!root) {
  console.error('usage: patch-plugin-rsc.ts <path-to-@vitejs/plugin-rsc>');
  process.exit(1);
}

const distDir = join(root, 'dist');
const files = (await readdir(distDir)).filter(
  (f) => f.startsWith('plugin-') && f.endsWith('.js')
);

const NEEDLE =
  'return `export {${Object.values(manager.clientReferenceMetaMap).find((v) => v.packageSource === source).exportNames.join(",")}} from ${JSON.stringify(source)};\\n`;';

const REPLACEMENT =
  '{ const _m = Object.values(manager.clientReferenceMetaMap).find((v) => v.packageSource === source); return _m ? `export {${_m.exportNames.join(",")}} from ${JSON.stringify(source)};\\n` : `export * from ${JSON.stringify(source)};\\n`; }';

let patched = 0;
let skipped = 0;
for (const file of files) {
  const path = join(distDir, file);
  const content = await readFile(path, 'utf8');
  if (content.includes(REPLACEMENT)) {
    skipped++;
    continue;
  }
  if (!content.includes(NEEDLE)) continue;
  await writeFile(path, content.replace(NEEDLE, REPLACEMENT));
  console.log(`  patched ${file}`);
  patched++;
}

console.log(`\npatched ${patched} files (${skipped} already patched)`);

You can reproduce both error on same zip file, one by one. Apply first patch and then you'll get another error (related to #1008 , exportNames).

Also I'll try to file a bug on vite-plugin-react also, but they require live demo url for reproduction. Will try with github link there.

[james-elicx]

The bug is in the RSC plugin or Vite from what I can tell - relative imports within our library should work fine...

[eashish93]

Linked here the bug I filed (description auto-gen via claude): vitejs/vite-plugin-react#1207