Direct streams now ignore late controller calls (
4ff9193)
A type: "direct" stream no longer accepts write()/close() calls that happen after end() or close() inside the same pull(). This fixes cases where late writes were still being buffered or where close/error ordering produced the wrong outcome.
Cloned request bodies now error instead of ending on failure (8d21080)
When a cloned body fails mid-stream, the original reader is now errored consistently instead of cleanly ending with { done: true }. That keeps truncated uploads from being mistaken for complete bodies.
Body consumption and locking are now tracked independently (83e2e4b)
Bodies now preserve their own bookkeeping even when the underlying stream source changes, fixing cases where cloned or blob-backed bodies lost the right bodyUsed/locking behavior. This also aligns Bun more closely with Node and browser behavior for locked streams and consumed bodies.
Terminal wrappers are released correctly after PTY EOF (90431a2)
Bun.spawn({ terminal }) now drops its wrapper and callbacks once the child side is gone and buffered input can no longer drain. That fixes leaked PTY resources and the CPU spin/memory growth seen when input was still queued at EOF.
Spawn no longer blocks the JS thread when pidfd_open fails (f86be9d)
If Bun runs out of file descriptors while spawning, it now kills and reaps the child without doing a blocking wait4() on the JS thread. This removes a Linux-only freeze path at fd exhaustion.
--compile --bytecode gets build-time optimization controls and faster startup (
5f55496)
The standalone executable path now carries pre-resolved module graph data and exposes a new startup JIT policy knob, letting compiled apps stay in the interpreter longer during boot. Bun also adds --no-optimize-bytecode / optimize.bytecode to skip bytecode optimization passes when desired.
Native sinks now root controller state correctly and avoid a leaked flush promise (5eba206)
This refactor changes how direct/native sink plumbing keeps the readable stream alive while piping, and fixes a promise that could be left hanging when end() hit backpressure. It also makes stream teardown more explicit across the sink pipeline.
HTMLRewriter now cancels still-open JS inputs on failure or abort (9685ae9)
When rewrite output is cancelled or the rewrite fails, the upstream JS stream is now cancelled too instead of being left to keep producing. That restores the expected backpressure/abort behavior for direct inputs.
Direct-stream responses now end exactly once (e3b6d63)
A Bun.serve direct stream that ends and then throws in the same pull() no longer writes the HTTP chunked terminator twice. This prevents response framing corruption that could break keep-alive clients.
bun test --isolate no longer charges deferred cleanup to the wrong file (d797369)
Deferred work from a retired test file is now dropped before it can run in a later file’s context. That fixes a flaky isolation bug where cleanup could abort the rest of the suite.
node:vm now throws defineProperty errors in the vm realm (8547bde)
TypeErrors raised during Object.defineProperty inside a vm context are now created in the sandbox realm instead of the host realm. That closes a cross-realm prototype leak that could expose host process.
fetch() no longer reuses poisoned pooled connections (f3e5bdd)
Bun now avoids reusing keep-alive sockets that the origin has already written to, preventing stale wire bytes from being misattributed to the next request. This fixes a real request/response mix-up hazard in connection pooling.
Other misc changes
- Misc direct-stream behavior fixes and tests
- Stream/fetch body contract and locking tests
- Documentation updates for bytecode and direct streams
- Dependency/baseline and internal cleanup changes