[JakeGinnivan]

Why

Vite 8 prints this on every dev and build:

Your Vite config uses features that are unsupported by configLoader: 'native', which is planned to become the default in a future major version of Vite

Nothing is broken today — we're on the default bundle loader, which resolves extensionless imports fine — but the warning is noisy and the underlying incompatibility is real. Rather than silence it with VITE_CONFIG_NATIVE_IGNORE_WARNING, this fixes the imports so the config graph resolves as genuine Node ESM.

The warning only scans the config module graph — vite.config.ts and what it transitively imports at config-load time: vite.config.ts → conference-stub/build-manifest.ts → manifest.ts → config/years-index.ts → the year files → venues.

conference-stub is the seed /new-conference copies for each new fork, so fixing it here stops every new conference inheriting the warning.

What changed

• .ts on relative imports across the config graph (conference-stub, themes, theme-builder, vite.config.ts). Matches the existing convention in website/e2e/, which Node already runs directly.
• @ddd/conference-config → module/moduleResolution: NodeNext. It's an extracted library, so resolving it as real Node ESM rather than through a bundler's lenient lookup keeps it honest. Bundlers understand the fully specified form too.
• allowImportingTsExtensions on the conference-stub tsconfig (already noEmit, so nothing is rewritten on the way out). Deliberately not added where it isn't required — nodenext accepts .ts specifiers under noEmit on its own.
• Widened the theme-builder module-boundary allowlist to accept an optional .ts. It anchored on the bare specifier (.../theme-builder$), so adding the extension would otherwise resurface the boundary error in conference-stub's themes. This was caught the hard way downstream — it turned the fork's CI red.

One case the warning cannot report

Vite's compat check only scans relative imports, so this stayed invisible until the config was actually run under the native loader:

Cannot find module '.../safe-routes/vite'
Did you mean to import "safe-routes/vite.js"?

safe-routes ships no exports field — just main plus a bare vite.js. Native Node ESM needs the explicit extension for that subpath. Now imports safe-routes/vite.js. Had we only suppressed the warning, this would have surfaced as a hard build failure on a future Vite major.

Verification

Check	Result
tsc -b --force	exit 0, no diagnostics
nx run-many --target=test --all	328 passed / 33 files
nx run-many --target=lint --all	0 errors across all 3 projects (2 pre-existing warnings in generated worker-configuration.d.ts)
vite build	✓ 3.42s + 818ms, zero warnings
vite build --configLoader native	✓ exit 0
Native ESM import of stub + lib graphs	both load

The --configLoader native row is the point: this is compatible with the future default, not just quiet about it today.

Relationship to the fork

This is the core half of dddwa/dddperth#151, which landed the same change for the fork's conference/ layer. The fork carries its own copy of the eslint allowlist (one level deeper, core/website/...), fixed there separately. Forks will pick this up on their next /pull-upstream.

https://claude.ai/code/session_012ZUK9WJ1TGNQzBSNwwrBx1