SvelteKit: a third-party package's void/db gets the D1 client in dev, and pg/MySQL builds inline workerd-only dependency code #420

Problem

a. A package that imports void/db gets the D1 client in dev

In a SvelteKit app with database: 'pg' (or MySQL), the app's own void/db is the generated pg client. A package in node_modules that imports void/db gets Void's static D1 client instead. Using it throws:

db: Missing Cloudflare binding 'DB'. This app connects through HYPERDRIVE or DATABASE_URL, but its server
bundle loaded the D1 client. In Nuxt or Analog, add 'void/nitro' to the Nitro modules.

The message also points SvelteKit users to Nuxt and Analog, which does not help them.

app route ── import 'void/db' ──> Vite SSR graph ──> generated pg client      (ok)
xa-db-lib ── import 'void/db' ──> Node (package is external) ──> dist/runtime/db.mjs (D1 client)

b. pg/MySQL builds inline workerd-only dependency code (risk)

For SvelteKit pg/MySQL builds, #413 builds Kit's ssr environment for workerd: resolve.noExternal: true, workerd/worker conditions and neutral output. Kit's analyse step then loads that output in Node. A dependency whose workerd build statically imports a cloudflare: module would now be bundled into that output, and Node cannot load it (ERR_UNSUPPORTED_ESM_URL_SCHEME). Before #413 such a dependency stayed external, and Node loaded its Node build.

This was seen only with a synthetic package (exports: { workerd: './cf.js', default: './node.js' }, where cf.js has import { connect } from 'cloudflare:sockets'). The server entry then started with import "cloudflare:sockets". No real package has been shown to break. pg is fine: pg-cloudflare imports cloudflare:sockets lazily.

Repro

a.

1. SvelteKit app, void.config.ts with database: 'pg', a pg schema, and DATABASE_URL in .env.
2. Add node_modules/xa-db-lib/index.js:

   import { db } from 'void/db';
   export function libDb() {
     try { return { execute: typeof db.execute }; } catch (e) { return { error: String(e) }; }
   }

3. Add src/routes/api/lib/+server.ts, which returns { app: typeof db.execute, lib: libDb() }.
4. vp dev, request /api/lib:

   {"app":{"execute":"function","run":"undefined"},"lib":{"error":"Error: db: Missing Cloudflare binding 'DB'. ..."}}

b. Add a dependency whose workerd export statically imports cloudflare:sockets, import it from server code in a SvelteKit pg app, and run vp build.

Cause

• a. Vite's SSR graph externalizes a package that resolves into node_modules. Void inlines only void itself (packages/void/src/plugin-framework.ts:232, ssr.noExternal: ['void']). The external package's void/db goes to the package export ./dist/runtime/db.mjs, the static D1 client (packages/void/src/runtime/db.ts:59-70). packages/void/AGENTS.md:101 notes that such packages load their own env module copies; void/db has the same limit.
• b. packages/void/src/plugin-framework.ts:310-330 (void:sveltekit-worker-build): noExternal: true at :325, conditions at :322, platform: 'neutral' at :329.

Suggested fix

• a. In SvelteKit dev, inline packages that import void/* (for example, find them in the dependency graph and add them to ssr.noExternal). At least, make the D1 client's error name the real cause for SvelteKit.
• b. Inline only the driver chain that void/db needs (void, drizzle-orm, pg, pg-*, mysql2 and their dependencies), and leave other dependencies to Kit's Node resolution. Or document the limit. Check real packages first, for example postgres (its cloudflare build).

Evidence

• a. Reproduced at the head of fix(void): make PostgreSQL and MySQL void/db work across frameworks, builds and deploys #413 with a workspace-linked void (response above). fix(void): make PostgreSQL and MySQL void/db work across frameworks, builds and deploys #413 makes the app's own void/db work with an installed void; it does not change a third-party package's import, and it adds the Nuxt/Analog wording to the error.
• b. Synthetic probe only, built with the head of fix(void): make PostgreSQL and MySQL void/db work across frameworks, builds and deploys #413. The SvelteKit build plugin is new in fix(void): make PostgreSQL and MySQL void/db work across frameworks, builds and deploys #413 (bd1705f26); before it, pg/MySQL SvelteKit Workers failed at request time instead.

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