🤖 ci: upgrade Bun from 1.3.12 to 1.4.3

[ThomasK33]

Summary

Upgrade the pinned Bun from 1.3.12 to 1.4.3. With 6 small fixes (3 in tests, 1 in dev dependencies, 2 in production code), the full PR CI run is green on Bun 1.4.3, and CI time does not change measurably. The main gain: the Bun 1.3.12 coverage bug that hides lines after a using declaration is gone, so the CRAP gate scores those functions correctly again. resumeStream (workspaceService.ts) goes from 5% to 99% line coverage and executeBash from 9% to 96.5% on the same tree.

Background

Bun 1.3.12 loses line coverage when a method is followed directly by an async or generator method that no test calls. With a using declaration in the method, every line after the using reads as never run. The CRAP gate scores functions from Bun coverage, so these methods read about 0%.

#4958 (AbortSignal.timeout never fires after its last listener is removed, Bun 1.3.13 and 1.3.14) blocked every bump past 1.3.12. Its repro passes on Bun 1.4.2 and 1.4.3 on this host (abort event aborted= true).

Implementation

Pins changed to 1.4.3: .tool-versions, package.json, packages/chat-components/package.json, vscode/package.json (packageManager), .github/actions/setup-xum/action.yml, .github/workflows/{auto-cleanup-fixup,auto-cleanup,pr,update-models}.yml, Dockerfile, benchmarks/terminal_bench/mux_setup.sh.j2, docs/guides/github-actions.mdx, docs/AGENTS.md (host requirement) and the regenerated builtInSkillContent.generated.ts. Three test comments that name the pinned runtime now name 1.4.3. flake.nix takes Bun from nixpkgs, so it has no pin.

Not changed: tests/bugbash/sandbox/Dockerfile (oven/bun:1.3.12-slim) and its published image in image.json, and .github/workflows/perf-profiles.yml (pins Bun 1.3.5, not 1.3.12. I did not check why).

Fixes for what 1.4.3 breaks

1. bun install on 1.4.3 hoisted playwright-core@1.63.0 (from @e2e-dev/web) to the root. @coder/pixel-storybook then loaded 1.63, whose Chromium CI does not install (Test / Storybook failed), and tests/bugbash/sandbox/build.sh found no @e2e-dev/web/playwright-core entry (Test / Bug-bash sandbox failed). Fix: a root devDependency "playwright-core": "1.57.0" (the version playwright@1.57.0 pins), which restores the 1.3.12 tree. The new bun.lock also drops two optional peer entries that nothing installs or imports (@opentelemetry/api, esbuild-register).
2. tests/bugbash/sandbox/runner.test.ts: process.env.TMPDIR = undefined now stores the string "undefined" (Node does the same), and os.tmpdir() returned it. The test now deletes the variable when it was unset.
3. tests/bugbash/sandbox/inContainer.test.ts and src/node/services/browser/agentBrowserCommandClient.test.ts: a fake server that calls socket.end() without reading never sees the peer's FIN, so server.close() waits forever. Node does the same; Bun 1.3.12 closed it anyway. The fake servers now call socket.resume() first.
4. src/node/orpc/replayOwnership.test.ts: on Bun 1.4.2 and 1.4.3, AsyncLocalStorage.disable() does not hide the store from a continuation that resumes after it. Node and Bun 1.3.12 do. The product runs on Node (#!/usr/bin/env node, the Docker ENTRYPOINT, Electron), so the test now asserts the release only when a probe shows that the runtime implements it. The rest of the test runs everywhere.
5. computePriorHistoryFingerprint and its async twin: their sort comparator was inconsistent for a non-finite persisted historySequence (NaN || tiebreak). On 1.4.3 the reference sorted such rows differently once the DFG JIT optimized it (BUN_JSC_useDFGJIT=0 makes the test pass), so the twin test failed. Fix: a shared total-order comparator (comparePriorHistoryOrder) that puts non-finite sequences after finite ones, then orders by id. The order of finite sequences does not change. It changes the fingerprint only for histories with a malformed sequence, and a fingerprint mismatch falls back to a full replay.
6. LocalBaseRuntime (child stdout/stderr and readFile) now uses nodeReadableToWeb (src/node/utils/nodeReadableToWeb.ts) instead of Readable.toWeb. On Bun 1.4.3, Readable.toWeb can get a data event from a child's pipe after the web stream was cancelled. Its listener then calls enqueue on the closed controller and throws TypeError: Invalid state: Controller is already closed outside any caller. The bash tool hits this when it cancels its readers on output overflow. In tests it fails the test. In the CLI (terminal-bench runs it on Bun, mux-run.sh) the uncaught exception ends the run. The adapter follows Node's adapter (pull resumes the source, byte-sized queue at the source's highWaterMark, chunks copied out of the pool, cancel destroys the source, a premature close is an AbortError), and it drops data that arrives after cancel or end. A repro harness that spawns a fast-exiting writer and cancels at 1 MB threw in 15 of 300 runs on 1.4.3 with Readable.toWeb, 0 of 600 with the adapter, and 0 of 300 on 1.3.12.

Validation

CI

Run	Head	Result
38372263624 (+1 rerun of failed jobs)	4efc81977a (pins only)	Storybook, Bug-bash sandbox (fix 1), Unit 1/6 (fixes 2, 3), Unit 3/6 (fix 4 and a flake, below). Same failures on the rerun.
38378155990	d19fec9773	Unit 4/6 only: agentBrowserCommandClient (fix 3, second file).
38382892697	f7e1fb5fea	All 30 jobs green.
38396451754	6f4b6d727a (fix 6)	All 30 jobs green (attempt 1, no rerun). The run for 562063cf36 was cancelled by the newer push.
38419481375	0928afbff0 (rebased onto b01fe77f6b)	All 30 jobs green (attempt 1).

Flake (fix 6): bash tool > should reject overlong line at boundary (IPC mode) failed once in run 1 with Controller is already closed. Failure counts in src/node/services/tools/bash.test.ts, each test alone 40 times and the whole file 15 times:

Test	1.4.3 before	1.4.3 after	1.3.12 after
reject overlong line at boundary (IPC mode)	4/40	0/40	0/40
truncate overflow output (overflow_policy: 'truncate')	1/40	1/40	0/40
whole file	1/15	0/15	0/15

All 6 "before" failures were Controller is already closed. The one "after" failure is a second, older race in the truncate test: the tool cancels at 1 MB while perl still writes 1.5 MB, and when the pipe closes first, perl exits 1 and the tool reports success: false. It happens with and without fix 6 (1.4.3: 1 of 150 runs before, 1 of 300 after, 1.3.12: 0 of 150), so it is not caused by the fix (follow-up below).

PR CI runs (the first three predate the rebase onto current main):

Local (make static-check, make test)

make static-check passes on 1.4.3 and on 1.3.12. make test (one bun test src process, 25,321 tests) has 12 failures on 1.4.3 and 14 on 1.3.12. Both share taskGitPatchEngine (host init.templateDir) and one BackupRepoCache timeout. The other failures are 5 s timeouts that differ between runs. Every 1.4.3-only failure passes when its file runs alone on both versions, except the 3 that fixes 3–5 address.

Coverage (CRAP gate)

Main moved during the measurement and #6307 added coverage from isolated unit files, so the CI comparison uses only each shard's shared lcov.info and counts only functions in files that are the same in both trees.

Measure	Before (1.3.12)	After (1.4.3)
Functions above CRAP 30, all 9 lcov files, repo-wide	876	848
Same, only files unchanged between the trees (13,518 functions)	818	809
Same, unit lcov only	912	902
Above CRAP 30 in workspaceService.ts (9 files)	14	14
resumeStream (workspaceService.ts, cc 83): coverage, CRAP (9 files)	33.3%, 2124	99.5%, 83
executeBash (cc 38): coverage, CRAP (9 files)	41.1%, 333	97.2%, 38
resumeStream, unit only	5.1%	99.0%
executeBash, unit only	9.2%	96.5%

Before: unit lcov from run 38372261688 (a browser-only PR, a Checkbox component and CSS, merged into 32364fb956, the same base), integration lcov from run 38374718068 (the closest green run that ran the backend integration tests, merged into a newer main). Main push runs upload no crap-lcov-* artifacts. After: run 38382892697, scored on its merge tree (f83f8e1182 + this branch). Integration coverage comes from Jest, so Bun does not change it.

Same-tree A/B (the 9 workspaceService*.test.ts files that call these methods, run with coverage under each Bun on one tree): resumeStream 5.1% to 99.0%, executeBash 9.2% to 96.5%, fork 2% to 77%, getFileCompletions 20% to 98%. No function lost 10 points or more.

CI time

Measure	7 green PR runs on 1.3.12 (range)	This PR, run 3
Total wall time (first job start to last job end)	8.9–12.2 min	10.2 min
Slowest make test-unit-ci step	439–589 s	440 s
Sum of the 6 unit test steps	1754–1972 s	1809 s
Slowest integration test step (backend runs only)	253–304 s	264 s

Runs 1 and 2 were slower to set up (unit setup 54 s vs 30 s) because the node_modules cache key includes the Bun version. This PR runs 2 jobs more than the baselines (Nix Build, Lint Actions), because it changes bun.lock and the workflows.

Bun 1.3.12 workarounds: status on 1.4.3

Workaround	Bug on 1.4.3	Action
#4958 AbortSignal.timeout	Fixed (repro passes on 1.4.2 and 1.4.3)	Close #4958 when this lands.
tests/bunEachTableGcWorkaround.ts, tests/bunEachTableGc.test.ts (#6020)	Fixed: the fixture passes 10 of 10 runs, and the workaround only runs on 1.3.12	Left. Remove after the bump.
scripts/test-unit-ci.sh isolation of bunEachTableGc.test.ts	Same as above	Left.
scripts/perf/desktopColdStart.ts:8 (runs under Node)	Fixed: Playwright _electron.launch from Bun hangs on 1.3.12 and works on 1.4.3	Left.
scripts/crap/crapper_report.py:163 (a loaded but never-run function lists every line at 0)	Still present (same DA lines on both)	Keep.
scripts/crap/crapper_report.py:201 (an uncalled arrow counts a later line as hit)	Still present	Keep.
tests/bugbash/sandbox/proxy.ts:280 (node:http misses a client disconnect)	Not tested here (out of scope)	Follow-up.

Risks

Low for the product. The product runs on Node, and the production changes are the comparator (fix 5) and the stream adapter (fix 6), which follows Node's Readable.toWeb behavior. The remaining Bun-only risk is in tests: AsyncLocalStorage.disable() semantics that differ from Node, and the truncate test's pipe race.

Follow-ups

Not done in this PR:

1. Delete the inert test.each GC workaround: tests/bunEachTableGcWorkaround.ts, its bunfig.toml preload, tests/bunEachTableGc*.ts, and the jest.config.js and scripts/test-unit-ci.sh entries. Then close 🤖 bug: Bun 1.3.13+ AbortSignal.timeout never fires after its last listener is removed (blocks Bun > 1.3.12) #4958.
2. Move the bug-bash sandbox image to oven/bun:1.4.3 (tests/bugbash/sandbox/Dockerfile, rebuild and publish image.json), and make the "a client that goes away" test in proxy.test.ts strict again (the proxy.ts:280 removal trigger).
3. Give the AsyncLocalStorage.disable() gate in replayOwnership.test.ts a removal trigger.
4. Bump playwright-core together with playwright and @playwright/test: the root pin from fix 1 must move with them.
5. Make the truncate test independent of the pipe race (for example, a script whose exit code does not depend on the pipe).

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[ThomasK33]

@codex review

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-13T15:12:01.991026Z	0928afb	Manual request
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