Bun ships major Windows, install, and build-system gains

Big cross-platform features and tooling improvements

• Windows Terminal support via ConPTY: Bun.Terminal and Bun.spawn({ terminal }) now work on Windows, bringing PTY-style child process support with docs and tests.
• Isolated installs get a global virtual store: warm installs now symlink from a shared store by default, making repeated installs and multi-checkout workflows much faster.
• FreeBSD and Android cross-target publishing expands: the release pipeline now supports new x86_64/aarch64 FreeBSD targets alongside Android, widening Bun’s build and artifact matrix.

Builds and CI got significantly faster

• Build graph and C++ compilation were streamlined: vendored C/C++ deps now build as first-class ninja edges, POSIX stops compiling libuv unnecessarily, and Windows gets unified C++ wrappers plus stronger PCH wiring.
• Zig/ASAN and CI throughput improved: the Zig shard merge step was removed for large builds, ASAN stack handling was tightened, and CI gained macOS rebalancing plus image prefetch caches.
• Binary-size and release packaging got cleaner: release and canary comparisons were adjusted to reduce noise, Linux release binaries strip more debug data, and build scripts/docs were updated around the new workflows.

Runtime correctness and crash fixes across core APIs

• Spawn/file-descriptor handling was hardened: extra stdio fds now preserve caller ownership, child stdin pipes are closed on early exit, and shell/subprocess cleanup fixed multiple fd/memory leaks.
• Install and module resolution bugs were fixed: tarball failures no longer hang the installer, auto-install no longer reads dangling dependency state, and bunx avoids accidentally resolving unrelated system binaries for scoped packages.
• Networking and process APIs improved: WebSocket clients now honor perMessageDeflate: false, client response timeouts no longer keep the event loop alive, and Windows error translation no longer panics on unmapped libuv codes.
• Hot reload and source handling were made more robust: macOS watcher re-registration was fixed, rejected-module reload races no longer use stale sourcemaps, and Bun.pathToFileURL() now handles very long relative paths safely.
• Terminal/TTY and GC-sensitive crashes were fixed: exit-time TTY restoration no longer clobbers downstream raw mode, and immediate callbacks/spawn cleanup no longer crash or leak after GC.

Engine and language/runtime updates

• WebKit was upgraded to a newer upstream snapshot: Bun absorbed a major engine sync that required broad jsCast/jsDynamicCast migration and updated baseline allowlists.
• using syntax is preserved when targeting Bun: explicit resource management is no longer lowered unnecessarily because JSC supports it natively.
• SQL and TLS behavior were corrected: MySQL prepared queries now wait for all result sets, and getCACertificates('system') reliably returns the OS trust store.
• Safer low-level conversions and memory handling: several double-to-int paths now use defined truncation helpers, and standalone binaries free embedded source pages after startup to reduce memory pressure.

Other misc changes

• mock.module() now validates its callback before resolver side effects.
• bun test --changed now respects tsconfig path aliases.
• SQLite was bumped to 3.53.0.
• Various docs, tests, flaky-test deflakes, symbol/baseline updates, and internal cleanup landed throughout the week.