Goal

Execute tranche 2 in /Users/zbeyens/git/slate-v2: land React 19.2 plus the latest Next baseline in one behavior-preserving runtime/site compatibility lane.

Scope

• root/site React + Next upgrades
• forced package/runtime compatibility fallout
• optional slate-browser landing only if genuinely non-conflicting
• no engine semantics work

Phases

1. inventory current repo + draft lane + relevant learnings
2. choose exact target versions and impacted files
3. implement dependency/config/source compatibility changes
4. verify install/build/typecheck/lint/test
5. update tranche docs/ledgers if needed

Constraints

• tranche rule: Next upgrade belongs here, not tranche 1
• repair-drift: same-path source first, minimum forced drift only
• review stop still applies after tranche completion

Findings

• Registry targets used for this slice:
  • react / react-dom: 19.2.5
  • @types/react: 19.2.14
  • @types/react-dom: 19.2.3
  • next: 16.2.4
• Next 16 no longer accepts eslint inside next.config.js.
• Next 16's route bundling choked on the template-string example importer because it pulled examples/ts/custom-types.d.ts into the route bundle. The explicit importer map from the draft lane fixes that without widening runtime drift.
• React 19 type fallout was small and local:
  • stricter useRef initialization
  • null-aware ref object typing
  • React.InputEvent on the editable input handler

Progress

• started tranche 2 execution
• upgraded root to React 19.2.5 and Next 16.2.4
• updated site config for Next 16 (top-level turbopack, .next/types TS include, removed invalid eslint config, no forced webpack)
• fixed the explicit tranche-2 source fallout in slate-react
• recovered the explicit example importer map so Next 16 stops bundling custom-types.d.ts
• verification passed:
  • pnpm install
  • pnpm turbo build --concurrency=1 --filter=./packages/slate --filter=./packages/slate-history --filter=./packages/slate-hyperscript --filter=./packages/slate-dom --filter=./packages/slate-react
  • pnpm turbo typecheck --concurrency=1 --filter=./packages/slate --filter=./packages/slate-history --filter=./packages/slate-hyperscript --filter=./packages/slate-dom --filter=./packages/slate-react
  • pnpm typecheck:site
  • pnpm build
  • pnpm lint:fix
  • pnpm lint
  • pnpm test