v2 migration: duplicate solid-js copies break client-side routing with unclear router error

Summary

After migrating a small site from SolidStart v1 / Vinxi to SolidStart v2 / Vite / Nitro, client-side navigation broke in a non-obvious way:

• Clicking a route link updated the browser URL.
• The rendered page stayed on the previous route.
• The console error was:

TypeError: Cannot read properties of null (reading 'push')

Root cause

The app and @solidjs/start ended up with different copies of solid-js under pnpm:

• app: solid-js@1.9.10
• @solidjs/start@2.0.0: solid-js@1.9.14

That split Solid's reactive owner/context across module instances, so router context was null at runtime.

Workaround

Pin and force a single solid-js copy:

{
  "dependencies": {
    "solid-js": "^1.9.14"
  },
  "pnpm": {
    "overrides": {
      "solid-js": "^1.9.14"
    }
  }
}

After deduping, client-side navigation worked locally and on the Netlify deploy preview.

Request

Could SolidStart or Solid Router detect duplicate solid-js instances and surface a development-time error, or could the v2 migration guide call this out explicitly? The current runtime error does not point toward dependency duplication, which made this difficult to diagnose.

Environment

• @solidjs/start: 2.0.0
• @solidjs/router: 0.16.3
• solid-js: 1.9.10 and 1.9.14 before dedupe
• vite: 8.2.1
• nitro: 3.0.260610-beta
• pnpm: 10.33.4
• Node: 24.19.0
• Deployment: Netlify

Start by reviewing the SolidStart v2 migration guide and the router behavior described for duplicate solid-js installations. Determine whether the requested outcome is a development-time diagnostic or migration documentation, then verify that the guidance or error clearly identifies dependency duplication and preserves working client-side navigation after deduping.