CI throughput improves for macOS and build images
The macOS test fleet was rebalanced and the launcher script was brought up to date for launchd-based runners, while Buildkite images now bake in dependency and test-docker prefetch caches (
75b7475, 64c585b, 3429283, 
2883530). This should cut redundant jobs, reduce network fetches, and raise CI throughput materially.
Fix Bun.pathToFileURL crash on long relative paths
Bun.pathToFileURL() no longer panics when a relative path expands past the old 4096-byte join buffer; it now falls back to heap allocation for oversized inputs (
ba8aec1). The new tests cover both very long paths and long paths with .. normalization.
Windows teardown overflow is fixed
The Windows event loop now uses saturating active-handle accounting during activate/deactivate and process teardown, preventing the integer overflow seen after spawning hundreds of subprocesses (03723c2). This removes a flaky exit-time crash that only showed up under heavy subprocess churn.
Immediate callbacks no longer crash after GC
JSRef.downgrade() now safely no-ops once a ref is already finalized, instead of asserting unreachable during immediate-task cleanup (583cd86). That closes a GC-sensitive crash triggered by clearImmediate(setImmediate(...)) followed by collection.
ASAN no longer breaks MarkedArgumentBuffer stack semantics
ASAN defaults for Bun were moved into a directly linked Zig object and the MarkedArgumentBuffer bridge is explicitly suppressed so its inline storage stays on the real stack (def5676). This fixes an intermittent sanitizer-only crash caused by stack values being collected too early.
Other misc changes
- Fixed Windows build flags and link/config mismatches.
- Removed a redundant macOS release-13 test split.
- Loosened a Windows socket memory-leak test bound.
- Ported WebKit JSPI wasm stress tests.
- Deleted an unnecessary integration test.
- Bumped the bundled old Bun version used in CI image builds.