verify

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1---2name: verify3description: Verify a Bun runtime change by driving the debug binary end-to-end.4---5 6# Verify a Bun runtime change7 8Build and drive the debug binary directly — never `bun test`, never import-and-call.9 10## Build11 12```sh13bun bd --version   # builds ./build/debug/bun-debug and prints its version14```15 16## Drive17 18For any JS-visible change, run the debug binary with `-e` and observe stdout:19 20```sh21bun bd -e '<repro>'   # builds, then runs; sets BUN_DEBUG_QUIET_LOGS for you22```23 24For worker/subprocess-shaped changes, spawn a subprocess (still `-e`) so worker teardown / event-loop-idle paths are exercised. Cross-check against `node -e '<same repro>'` for Node-compat changes.25 26## Gotchas27 28- **A `src/js/**` edit can silently not reach the binary.** `bundle-modules`29  regenerates `build/<cfg>/codegen/InternalModuleRegistryConstants.h`, but the C++30  TU that embeds it is not always recompiled, so the build succeeds while the31  binary still runs the OLD JS. Gate on the binary, not the build: ask the binary32  you just built — `bun bd -e 'console.log(<Class>.toString().includes("<new-id>"))'`33  (or run `./build/<cfg>/bun` directly). Plain `bun` is the system Bun on $PATH and34  never has your edit, so it answers about the wrong binary.35  If false, `touch src/jsc/bindings/InternalModuleRegistry.cpp` and rebuild.36- **Prefix every `bun bd` with `PATH="$HOME/.cargo/bin:$PATH"`** — Homebrew's `rust`37  formula shadows the pinned nightly, and `bun bd` dies with `the option 'Z' is only38  accepted on the nightly compiler`. `bun bd` re-runs cargo on every invocation, so39  this is needed for follow-up runs too, not just the first build.40- `node:cluster` changes can't be driven with `-e`: `cluster.fork()` re-execs `argv[1]`, so workers need a real file on disk. Write a scratch script and run `./build/debug/bun-debug <file>`.41- Only one `bun bd` per worktree at a time — a second one blocks on the build lock and looks like a runtime hang. Build once, then drive `./build/debug/bun-debug` directly under `timeout`.42- `BUN_DEBUG_QUIET_LOGS=1` suppresses debug-build log spam.43- Debug builds print `[cachefs]`/`[sys]` lines to stdout; filter them before diffing44  output against `node`.45- MessagePort's `.on/.off` are added by requiring `worker_threads` — plain `new MessageChannel()` ports only have `addEventListener` until then.46- The debug+asan build is 10-100× slower than release; large-allocation stress tests can time out locally while passing in CI.47