# Contributor handoff — vuejs/core

> Canonical page: https://codevetter.com/unpack/vue/agent-handoff

# Contributor handoff — vuejs/core

Scanned commit 4ab865a848a1da3d10fb674f857e5fff13094644 (2026-09-18). Generated by codevetter codevetter 1.12.0 on 2026-09-22.

Read the contributing guide's Project Structure and Package Dependencies sections before touching anything — the import rules there are enforced by both eslint and the release process. Expect ES2016-target lint restrictions that will reject idiomatic modern TypeScript, and expect every dev-only behaviour to be guarded by a `__DEV__` flag that must tree-shake cleanly. The fastest verification loop is `pnpm test-unit <package>`; the slowest and most CI-relevant are `pnpm check`, `pnpm test-dts` and `node scripts/verify-treeshaking.js`. Never reach across packages with relative paths, and never add a runtime import to a compiler package.
- Read first, in order: `.github/contributing.md` (scripts + project structure), `package.json` (the script surface), `vitest.config.ts` (which project your test will land in), and `scripts/aliases.js` (how `@vue/*` resolves in tests and builds). — [.github/contributing.md#L106-L318](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/.github/contributing.md#L106-L318) [package.json#L6-L37](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L6-L37) [vitest.config.ts](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/vitest.config.ts) [scripts/aliases.js](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/aliases.js)
- The eslint config bans object rest/spread, `await`, optional chaining and `const enum` repo-wide with explicit rationale messages (ES2016 output target, esbuild helper bloat, enum inlining); use `extend` from `@vue/shared` instead of object spread. — [eslint.config.js#L11-L55](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/eslint.config.js#L11-L55)
- `no-restricted-globals` is scoped by directory: DOM globals are banned everywhere except `packages/{vue,vue-compat,runtime-dom}` and shared; Node globals are banned in DOM packages; `import-x/no-nodejs-modules` allows bare (non-`node:`) builtins only under `packages/compiler-sfc/src/**`. — [eslint.config.js#L104-L170](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/eslint.config.js#L104-L170)
- Safe edit boundary: a change confined to one package's `src` plus its `__tests__` is verifiable with `pnpm test-unit <pkg>`; anything touching `renderer.ts`, `component.ts`, `scheduler.ts` or `vnode.ts` needs the full `pnpm test-unit` plus `pnpm test-e2e` because runtime-test, SSR and hydration all ride on them. (inferred) — [packages/runtime-core/src/renderer.ts](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/runtime-core/src/renderer.ts) [package.json#L17-L19](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L17-L19) [.github/contributing.md#L209-L231](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/.github/contributing.md#L209-L231)
- Trap: any new public export must also be re-exported at the package index — direct relative imports across package boundaries are forbidden, and a non-type import from package B requires B to be listed in A's package.json dependencies because the packages are externalised in ESM/CJS builds. — [.github/contributing.md#L307-L317](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/.github/contributing.md#L307-L317) [packages/runtime-dom/package.json](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/runtime-dom/package.json)
- Trap: commit messages are validated by a regex in `scripts/verify-commit.js` limited to a fixed type list with a ≤50-character subject; a non-conforming message fails the commit-msg hook outright. — [scripts/verify-commit.js#L9-L28](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/verify-commit.js#L9-L28) [package.json#L39-L42](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L39-L42)
- Trap: the pre-commit hook runs `pnpm lint-staged && pnpm check`, so a full `tsc --incremental --noEmit` over the whole repo runs on every commit — type errors in unrelated packages will block an otherwise-clean change. — [package.json#L38-L41](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L38-L41) [package.json#L14](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L14)
- Trap: `tsconfig.json` sets `isolatedDeclarations: true`, which means exported functions and consts need explicit return/value type annotations — this is why the codebase writes `export const version: string = __VERSION__` and `export function initDev(): void`. — [tsconfig.json#L25-L26](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/tsconfig.json#L25-L26) [packages/compiler-sfc/src/index.ts#L1](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/compiler-sfc/src/index.ts#L1) [packages/vue/src/dev.ts#L3](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/vue/src/dev.ts#L3)
- Convention: dev-only code goes inside `if (__DEV__)` or `__DEV__ && ...` rather than behind a runtime boolean, and new warnings should be asserted in tests with the custom `toHaveBeenWarned` matchers. — [packages/runtime-core/src/apiCreateApp.ts#L330-L346](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/runtime-core/src/apiCreateApp.ts#L330-L346) [scripts/setup-vitest.ts#L16-L40](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/setup-vitest.ts#L16-L40)
- Convention: compile-time optional features must be wrapped in the corresponding flag — `__FEATURE_OPTIONS_API__` for `app.mixin` and `applyOptions`, `__FEATURE_SUSPENSE__` for Suspense dispatch, `__COMPAT__` for Vue-2 behaviour — or the feature will not tree-shake and `verify-treeshaking.js` may fail. — [packages/runtime-core/src/apiCreateApp.ts#L310-L326](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/runtime-core/src/apiCreateApp.ts#L310-L326) [packages/runtime-core/src/renderer.ts#L471-L485](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/runtime-core/src/renderer.ts#L471-L485) [scripts/verify-treeshaking.js](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/verify-treeshaking.js)
- Tests to run before opening a PR, mirroring CI exactly: `pnpm run test-unit`, `pnpm run test-e2e`, `pnpm run lint`, `pnpm run format-check`, `pnpm run check`, `pnpm run test-dts`. — [.github/workflows/test.yml#L26-L125](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/.github/workflows/test.yml#L26-L125) [package.json#L14-L22](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L14-L22)
- To iterate on compiler output interactively use `nr dev-compiler` (template-explorer at `localhost:3000/packages-private/template-explorer/local.html`, opened by `nr open`); for full SFC behaviour use `nr dev-sfc`, which runs `pre-dev-sfc.js` and falls back to `build-all-cjs`. — [package.json#L24-L26](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L24-L26) [package.json#L33-L35](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L33-L35) [.github/contributing.md#L197-L208](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/.github/contributing.md#L197-L208)
- Never hand-edit `dist/` or generated `.d.ts` files: dist is rebuilt by `scripts/build.js` (which rm -rf's it for full builds) and declarations are regenerated by `build-dts`; `.gitignore` and the eslint `ignores` block both exclude `**/dist/` and `**/temp/`. — [scripts/build.js#L170-L176](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/build.js#L170-L176) [package.json#L8-L9](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L8-L9) [eslint.config.js#L172-L181](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/eslint.config.js#L172-L181)
- Versions across all packages are lockstepped at the root version (3.5.43) and rewritten by `scripts/release.js`, which reads and patches each package.json — do not bump a package version by hand. — [package.json#L3](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/package.json#L3) [scripts/release.js#L75-L90](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/scripts/release.js#L75-L90) [packages/compiler-core/package.json](https://github.com/vuejs/core/blob/4ab865a848a1da3d10fb674f857e5fff13094644/packages/compiler-core/package.json)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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