Mocks clear by default as Vitest reaches beta 6 and Turborepo ships Cargo workspace support

Vitest beta 6 rewrites the defaults

The most consequential release of the week is Vitest v5.0.0-beta.6, which carries multiple breaking changes that developers migrating to v5 will need to plan for. Most notably, mocks now clear automatically before each test — a shift from the previous behavior where vi.clearAllMocks() was opt-in per test or lifecycle hook. This could surface latent test pollution that was previously masked, but it aligns with the principle that tests should be isolated by default. The change also moves JSON and JUnit reporter output files to a .vitest directory instead of the project root, and the HTML reporter output follows suit. The beta also adds vi.when() for conditional mocking, support for mocking the Temporal API via updated @sinonjs/fake-timers, and a new screenshotDirectory config option for browser.expect.toMatchScreenshot. The webdriverio package has been removed, signaling a narrowing of browser runner integrations.

Alongside the beta, the project shipped patch releases for its stable branches: Vitest v4.1.10 and Vitest v3.2.7 both backport a fix for filesystem access checks in browser builtin commands, and the v4.1.10 release also resolves an external module resolution error in the VM optimizer when dealing with encoded URIs.

Turborepo embraces Rust toolchains

The biggest story in the monorepo tooling space is Turborepo v2.10.4, which introduces Cargo workspace support as a production feature. Turborepo can now discover Cargo crates as packages, execute cargo tasks, and make turbo watch and turbo prune Cargo-aware. This is a significant expansion of Turborepo's scope beyond JavaScript ecosystems, and it's backed by a raft of performance improvements: single-pass parsing for yarn v1 and Berry lockfiles, parallel pnpm lockfile section parsing, hardware-accelerated SHA-1 hashing, and concurrent workspace discovery and dependency hashing.

The v2.10.5-canary series that followed this week iterates on the Cargo integration. Canary 1 added embedded sccache caching, so the Remote Cache now serves as an sccache backend for Cargo tasks without requiring separate installation, and fixed lockfile detection fallback. Canary 2 and Canary 3 focused on stabilizing the compile cache — fixing ambient CARGO_INCREMENTAL suppression and ensuring cache storage failures don't fail the build. Canary 4 fixed pnpm patches with version range keys being removed during prune and extraneous bun.lock entries, while Canary 5 made npm prune rehoisting deterministic and added incremental cache reuse reporting. The series caps off with Canary 6, which disables Cargo run task caching by default and extends TUI text selection beyond the visible viewport.

Deno brings desktop apps closer to the browser

Deno v2.9.2 adds several features that make the Deno runtime more capable for building desktop applications. The new window opacity and transparency APIs give developers control over window chrome, while React Router framework autodetection and HMR support for Vite and Nuxt streamline the development workflow. The release also includes broad stream performance improvements across Web Streams and pipeTo operations, plus dozens of correctness fixes across Node.js compatibility, telemetry, and coverage reporting.