Bun closes several GC and lifetime holes (
7ab24e4, 
3360a9e, 3d125dc, 55f6c89, a1dd647)
Multiple core subsystems were tightened to avoid use-after-free, aliasing, and lifetime bugs: aggregate-error construction now keeps JS wrappers on the stack during GC-sensitive paths, CSS printing threads real lifetimes instead of erasing them, FFI drops a write-only field with clearer rooting rules, YAML removes raw parser back-pointers, and resolver slot pointers are now derived from the singleton with provenance-safe helpers.
ReadableStream locking and cancelation are fixed (d155a2c)
ReadableStream::isLocked was effectively broken and returned false for every stream; the fix aligns native checks with the JS builtins’ actual $reader/sentinel behavior. It also avoids mis-routing cancelation for direct streams and marks native cancel promises handled to prevent unhandled rejection noise.
Test isolation now cleans up leaked handles and timers (ef89527)
bun test --isolate now proactively closes leaked watchers/servers and cancels stale timers before swapping globals, so one file’s leftovers don’t pin the next file’s entire module graph. The same change adds a test-only hook to inspect isolated module cache state, improving coverage for the isolation machinery.
Bundler output dirs now own their file descriptors (f500993)
The bundler’s output-dir handle is converted from a raw duplicated FD into an owning bun_sys::Dir, so the descriptor is reliably closed instead of leaking through worker clones and downstream result structs. This is a real resource-management fix for long-running build paths.
fs.watch now stores its JS wrapper weakly (08226e2)
FSWatcher no longer keeps a bare self-reference that could pin the wrapper forever; it now uses JsRef with weak semantics and helper accessors. That matches the watcher’s actual liveness model and fixes a GC/rooting hazard around open/closed watcher lifecycle.
Zlib GC accounting no longer reads mutable stream state on the marking thread (74c709d)
NativeBrotli and NativeZstd now cache their estimated external size at construction so estimated_size can run safely during concurrent GC marking without touching JsCell-backed stream state. This removes a thread-safety violation in GC memory accounting.
CI now sanity-checks platform tags before tests run (
a7839df)
Buildkite smoke steps now declare their expected OS/arch/ABI/distro/release, and the runner aborts early if the agent doesn’t match. That prevents entire shards from wasting time on misrouted jobs and makes platform mismatches fail fast.
Base64 crash-path encoding no longer overflows on i32::MIN (91270aa)
The crash handler’s VLQ encoding path now avoids negating i32::MIN, which had been able to trigger a nested panic during crash reporting in debug builds. This hardens Bun’s panic reporting path so the reporter itself is less likely to abort.
Bundler and CSS correctness fixes land across minify and grid parsing (b56491b, 6038601, 3360a9e)
The minifier reuses parser-owned scratch storage instead of allocating per call, and grid-template-areas now correctly parses . null-cell tokens, including runs of dots. CSS module printing also got a safer lifetime model, which matters for emitted chunk generation.
Other misc changes
- Intel SDE is baked into the Windows verify-baseline image to avoid flaky job-time downloads (
a2eaf90) - SQL test now uses
container.hostfor remote Docker compatibility (82808d4) - Comptime string map refactor replaces workspace
phfusage (bf79fe7) bun test --isolateand various runtime paths got additional cleanup and test coverage (ef89527, 7ab24e4, 74c709d)- Resolver, YAML, CSS, FFI, bundler, and parser internal refactors/supporting tests (a1dd647, 55f6c89, 3360a9e, 3d125dc, f500993, b56491b, 6038601)