docs(cli): name the writer that actually made the first failing stderr write

[claude]

Fixes #16691

Clause-②: no

Explanatory text only, re-declared from the diff: three comment-only edits plus one changeset. No behaviour, no accept set, no exported member, no runtime contract. bin/run-dev.js's error listener, its 15 s bound and the warning collector are byte-identical; so is bin/run.js's named listener; so is every assertion in the touched test file.

Step one: who actually made the first failing write

The card left two readings it could not choose between. Neither is what the instrument shows, and the third answer is more useful than either.

The instrument

An --import observer that wraps process.stderr.write and nothing else. It installs no error listener on the stream and never attaches one from inside a write callback, so a raw write stays fatal and a console.error write stays protected by Console's own handler, which the observer forwards to. It logs the call site of every write, the code delivered to every completion, listenerCount('error') around each write, and every error emission with the names of the listeners present.

Both control legs, quoted

Plain node, read end destroyed (stdio: ['ignore','ignore','pipe'], then child.stderr.destroy()), child kept alive one turn. node v22.22.2.

leg	writes	verdict
A. one raw process.stderr.write	1 RAW	exit 1, uncaughtException EPIPE — 3/3
B. console.error, 1 MiB	1 console	exit 0 — 0/3
C. console.error, one short line	1 console	exit 0 — 0/3
D. 3x console.error in one tick	3 console	exit 0 — 0/3

The observer moves on both legs, in opposite directions, and says why:

leg A   cb W#1 RAW     err=EPIPE listeners=0 errorEmitted=false
        EMIT 'error' listeners=0 code=EPIPE names=
        UNCAUGHT code=EPIPE msg=write EPIPE
              at afterWriteDispatched (node:internal/stream_base_commons:159:15)
        EXIT code=1

leg D   cb W#1 console err=EPIPE listeners=0 errorEmitted=false
        cb W#2 console err=EPIPE listeners=1 errorEmitted=false      <- Console re-attached its noop
        EMIT 'error' listeners=1 code=EPIPE names=noop
        EXIT code=0

That is the required 3/3 raw and 0/3 through console.error, and the 0/3 is a real reading rather than a blind one: the EPIPE was delivered and observed on that leg too.

The shim legs

Same observer, tsx + the suite's own unbuilt-spec-dist.hook.mjs + destroyed read end, i18n extract nope.ts from a fresh temp cwd.

leg	result
bin/run-dev.js as shipped	exit 2, 0/3 crash, 179 writes, 178 failed
bin/run-dev.js with the #14858 listener ablated	exit 1, 3/3 crash, 87 writes, every one of them a console.error

Write order and bytes, taken from a draining reader so the totals are real (179 writes, 147 729 bytes):

order	writes	bytes	writer
#1	59	35 133	console.error from node's own default warning handler — writeOut (node:internal/process/warning:56) from process.onWarning (…:132)
#2	59	80 053	console.error from oclif displayWarnings() — config.js:69, warning.stack
#3	59	31 698	console.error from oclif displayWarnings() — config.js:71, warning.detail
#178	1	415	the only raw process.stderr.write — run-dev.js:113, i.e. writeStderr()
#179	1	430	console.error from oclif handle()

The reading this establishes

Reading 2 is falsified. There is no other raw write on that path. The only raw write is #178 of 179, and the crashing leg is dead at 87 writes — writeStderr() is never reached, exactly as #15558 already said.

Reading 1's conclusion is half right and its reason is wrong. The failing writes are console.error, but nothing is landing after kWriteToConsole's finally, and payload size is not the variable. The observer shows listeners=1 at every completion with errorEmitted=false: Console's createWriteErrorHandler declines to attach its keep-alive noop because the count is not zero.

The listener that occupies that slot is node's own. Traced with a second observer that logs every error-listener attachment on process.stderr:

ATTACH via prependListener: name=onerror
  src=function onerror(er) { cleanup(); if (EE.listenerCount(this,'error') === 0) { this.emit('error', er); } }
    at prependListener (node:internal/streams/legacy:111:20)
    at Readable.pipe (node:internal/streams/readable:1034:3)
    at pipeWithoutWarning (node:internal/worker:574:10)
    at new Worker (node:internal/worker:252:7)
    at new HooksProxy (node:internal/modules/esm/hooks:506:20)
    at ModuleLoader.register (node:internal/modules/esm/loader:683:30)

tsx calls module.register(), so node pipes the module-customization hooks worker's stderr into process.stderr, and Stream.prototype.pipe prepends onerror on the destination for the whole run. Console's keep-alive therefore never installs; onerror takes the first EPIPE, tears the pipe's listeners down including itself, finds nothing else listening and re-emits — and that second emit is the uncaught one:

EMIT 'error' listeners=1 code=EPIPE names=onerror
EMIT 'error' listeners=0 code=EPIPE names=
UNCAUGHT code=EPIPE msg=write EPIPE
      at afterWriteDispatched (node:internal/stream_base_commons:159:15)
EXIT code=1

One-variable ablation of exactly that mechanism, plain node, one short line, nothing else changed:

leg	result
E. console.error('one line') (= leg C)	exit 0 — 0/3
F. module.register() of a no-op hook, then the SAME console.error('one line')	exit 1, uncaughtException EPIPE — 3/3

And the mirror census on the published entry, measured rather than inferred: under plain node bin/run.js the only error listener on process.stderr for a whole run is that file's own objectstackStderrErrorIsNotFatal. So #16686's measurement is correct there, and it is the generalisation that was unsafe.

So both sentences needed work, for different reasons: run-dev.js:378 names the wrong writer, and run.js:106 states a conditional protection unconditionally. The two files were never really contradicting each other — the two entry points genuinely differ, and the discriminator is tsx's module.register(), not the payload size.

Per-site table — every displayWarnings() occurrence

Line numbers as measured on origin/main@ec5db7b44f (unchanged through fcddd151c3).

site	what it claims	changed?	reason
run-dev.js:66	settings.debug on, so displayWarnings() queued ~138 KB ahead of these lines	yes	Causal attribution of the backlog, and measurably incomplete: displayWarnings() wrote 111 751 of the 147 729 bytes; node's own default warning handler wrote the other 35 133. Now names both and carries the measured split.
run-dev.js:378	displayWarnings() makes the first write	yes	The card's sentence. Measured: write #1 is node's own default warning handler; displayWarnings() makes #2 and #3. The rest of the sentence (EPIPE, uncaught exception, 12/12, timings) stands unchanged.
run-dev.js:433	oclif installs its warning listener only when listenerCount('warning') <= 1	no	Listener install TIMING, not authorship. Untouched, verified byte-identical against HEAD.
run-dev.js:442	run() reaches Config.load() and displayWarnings() in its synchronous prefix	no	Listener install TIMING. Untouched, verified byte-identical.
run-dev.js:444	config.js: displayWarnings() precedes load()'s first await	no	Listener install TIMING. Untouched, verified byte-identical.
run.js:106	oclif's warning blocks cannot crash this process at any size	yes	Not a displayWarnings() occurrence, but the contradicting half. Its measurement is kept verbatim and its condition is now stated: the keep-alive attaches only while listenerCount('error') === 0, which is a fact about this entry point.
run-dev-unbuilt-workspace.e2e.test.ts:465-466	restates :378 near-verbatim	yes	Same correction, kept short, pointing at the shim docblock for the mechanism.
run-dev-unbuilt-workspace.e2e.test.ts:507	"nothing is making EPIPE non-fatal on process.stderr any more (see #14858 and the ablation table)"	no	Judged separately as the dispatch asked: it is a statement about the LISTENER, not about which writer wrote first. Untouched, verified byte-identical.

A new paragraph was added above run-dev.js's NOT narrowed to EPIPE note, carrying the mechanism and the one-variable ablation — that is the sentence a reader needs when asking "do console.error sites need guarding?".

Nothing else changed. git diff -U0 hunks: run-dev.js at 66, 381 and 405; run.js at 105; the test file at 464.

What this does NOT overturn

run-dev.js's 12/12 crash is real, the listener fix is correct, and this PR strengthens rather than weakens it: the ablated leg reproduces exit 1 at 3/3 here, and the new paragraph states that the listener is what covers the console.error sites too, not only writeStderr(). No behaviour is touched, the listener is neither removed nor narrowed, and nothing here reads as "the original fix was wrong".

Changeset — measured, not assumed

packages/cli's files[] is ["dist","README.md","CHANGELOG.md"] and names no bin/. It still ships bin/run.js, because npm packs a bin target regardless (#14874). Packed for real with npm pack --ignore-scripts and searched inside the tarball, exit codes captured before any pipe:

tarball contents:  ./CHANGELOG.md  ./LICENSE  ./README.md  ./bin/run.js  ./package.json
positive control  'objectstackStderrErrorIsNotFatal'   grep exit=0  ->  ./bin/run.js
SUBJECT (run.js)  'module-customization hook'          grep exit=0  ->  ./bin/run.js
SUBJECT (run-dev) 'Payload size decides nothing'       grep exit=1  ->  absent

The control fires on the same file the subject is found in, and bin/run-dev.js is not in the tarball at all. So one published file's bytes move and two do not: a changeset is owed, and .changeset/cli-epipe-writer-attribution.md declares @objectstack/cli: patch for the bin/run.js prose only. dist/ is absent from the listing only because the package was unbuilt at pack time; that is orthogonal, since no src/ file is touched.

Docs drift — re-derived, and its zero corroborated by hand

First run was against a dirty worktree with an empty diff range and is discarded as NOT MEASURED (dirty: true, diffBase == head, changedPackages: []). Re-derived after committing:

computedOn: {head: 709c4a021f…, diffBase: fcddd151c3…, dirty: False}
changedPackages: [{dir: packages/cli, name: @objectstack/cli}]
docs: []
anchorlessChanges: ['packages/cli/bin/run-dev.js', 'packages/cli/bin/run.js']
summary: … 1 test file(s) excluded … 2 changed file(s) yielded no anchor —
         this run cannot see pages documenting them

So the zero is the tool's own no-anchor mode, not a clean bill. Hand-swept content/ for this change's tokens, with a live positive control:

displayWarnings   grep exit=1   0 hits
EPIPE             grep exit=1   0 hits
run-dev           grep exit=1   0 hits
ignoreErrors      grep exit=1   0 hits
console.error     grep exit=0   22 hits, all client/server error-handling examples
                                (auth, realtime, error-catalog) — none about process.stderr
stderr            grep exit=0   4 hits: 3 generated logging-reference rows for the
                                `stream` enum, 1 in releases/v16.mdx about log routing
POSITIVE CONTROL  '@objectstack/cli'  grep exit=0   20 files

The sweep fires. No hand-written doc restates the corrected claim, so nothing under content/ moves. content/docs/releases/ was not touched.

Verification

Final HEAD 1727827692.

• node scripts/pm/dispatch-gates.mjs --commands --repo objectstack-ai/objectstack — 57 families derived; re-derived after the changeset existed and again against the newest origin/main (identical list, and "none of the commit(s) this tree can SEE touched what this answer derives from").
• All 57 run at the final HEAD: 56 exit 0, 1 exit 3. pnpm check:type-check-debt exits 3 = PREREQUISITE NOT MET — its tsc --re-measure child OOMed at the 4096 MB heap on this shared container ("refusing to record 0"), so it is NOT MEASURED, neither a pass nor a finding; pnpm check:type-check-coverage (the same checker's self-test plus the coverage clause) is exit 0. Declared to CI.
• node scripts/pm/dispatch-gates.mjs --ran … — "57 derived famil(ies) accounted for — 57 run, 0 NOT-MEASURED, 0 UNRUN".
• pnpm --filter @objectstack/cli typecheck — exit 0 (tsc --noEmit plus check:test-typecheck).
• pnpm --filter @objectstack/cli exec vitest run --project unit --maxWorkers=2 — 189 files, 2618 tests, exit 0.
• Integration tier, the file this PR edits: OS_TEST_TIERS=nightly … --project integration run-dev-unbuilt-workspace — 1 file, 11 tests, exit 0. It is a nightly-tier file (*.e2e.test.*), so the queue population does not collect it; it is run here because this PR edits it and because its SHIM_DRAIN_STALL_MS mirror case reads bin/run-dev.js as text.
• The other suites that spawn or read the two edited entries: published-entry-stderr-error-listener (6 tests, the pin on bin/run.js's named listener), published-entry-stderr-nonblocking and run-dev-stderr-nonblocking (10 tests) — all exit 0.
• Repo-wide lint, run in full rather than narrowed, from the final commit: eslint . --no-inline-config --format json — 6384 files, 0 errors, 0 warnings, exit 0. The build closure turbo run build --filter='@objectstack/cli...' is 57/57 successful.
• Control-byte self-scan beyond check:nul-bytes: grep -naP '[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]' over the three edited files — exit 1, clean.

Every exit code above was captured before any pipe.

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Generated by Claude Code

[github-actions]

📓 Docs Drift Check

⚠️ 2 changed file(s) yielded no anchor (packages/cli/bin/run-dev.js, packages/cli/bin/run.js), so the pages documenting them are NOT COVERED by this run — this is not a clean bill of health for those files. Nothing else in this diff resolved to a documentable surface (no symbol, route or SDK anchor derived from 1 changed package(s)).

What this run could not see

• 2 changed file(s) yielded no anchor (packages/cli/bin/run-dev.js, packages/cli/bin/run.js) — pages documenting those are invisible to this run
• a page that states a rule by its inputs shares no identifier with the emitter that implements the rule, so an emitter-only diff cannot list it — not on this run and not on any run. Measured on fix(driver-sql): emit varchar(maxLength) for a text field a declared index keys on #11430: content/docs/protocol/objectql/types.mdx documents the text-family column mapping by the ObjectQL type names it maps FROM (text / textarea / html) while the diff changed createColumn; it went unlisted, and it was the page that diff falsified, in four places. No shared token exists to detect this on, so a rule your change carries has to be re-read by hand in the pages that restate it.

Coarse fallback — 22 page(s) merely mention a changed package (the pre-#9192 predicate, kept for the deliberately-wide backstop): node scripts/docs-audit/affected-docs.mjs --json efd6b43ace6fd12bc3d8a9d130bc9702793258c8 → packageMentionDocs.

[os-project-manager]

PM review — accepted, arming

CI. 33 check-run rows, all terminal, 0 red. Every name is distinct on this head, so the latest-per-name collapse is 33 → 33 — stated though it changes nothing, because on two sibling PRs today it was 38 → 34 and 37 → 33, where raw would have double-counted.

Clause-② — exit 0, both carriers agree, no widening tell.

⭐ This card asked which of two readings was right, and the answer is neither. That is the most valuable outcome available on a card like this, and it was reached by instrument rather than argument. Reading 2 (another raw write) is falsified: the only raw process.stderr.write on that path is writeStderr() at run-dev.js:113, write #178 of 179, while the crashing leg is dead at 87 writes. Reading 1's conclusion is half right for the wrong reason: every failing write is a console.error, but payload size is not the variable.

The actual mechanism: tsx calls module.register(), so node pipes the hooks worker's stderr into process.stderr, and Stream.prototype.pipe prepends an onerror listener there for the whole run. Console's createWriteErrorHandler attaches its keep-alive noop only while listenerCount('error') === 0, so it never installs; onerror takes the first EPIPE, tears down the pipe's listeners including itself, finds nothing listening and re-emits — and that second emit is the uncaught one.

⭐ And it is proven by a one-variable ablation, not inferred from a trace. Plain node, one short line, nothing else changed: console.error alone → exit 0 (0/3); module.register() of a no-op hook plus the same console.error → exit 1, uncaught EPIPE (3/3). A no-op hook is exactly the right probe, because it isolates the registration from anything the hook does.

⭐ Equally important is the reading that neither sentence was lying: run.js:106's measurement is correct at that entry point — under plain node bin/run.js the file's own named listener is the only error listener for a whole run. Only its generalisation was unsafe. So the two files were never contradicting each other; the two entry points genuinely differ, and the discriminator is module.register(), not size. That is a better resolution than picking a winner.

⭐ My four dispatch fences held, and I verified that myself rather than reading the table. run-dev.js:433, :442, :444 (listener timing, not authorship) and the test's :507 (a statement about the listener, which the dispatch asked to be judged separately) are absent from the diff entirely — checked by grepping the diff for each claim, not by trusting the per-site table. 4 files, +78/−22, exactly as declared.

Changeset — measured, and the measurement is the interesting part. packages/cli's files[] is ["dist","README.md","CHANGELOG.md"] and names no bin/ — yet npm packs a bin target regardless (#14874), so reasoning from files[] would have reached the wrong answer in both directions. Packing the tarball for real settles it: ./bin/run.js ships and bin/run-dev.js does not, with the positive control (objectstackStderrErrorIsNotFatal, grep exit 0) firing on the same file the subject is found in. ⇒ one published file's bytes move, a patch changeset is owed, and it covers the run.js prose only. ⭐ This is the third time today the cheap skip-changeset guess would have been wrong, and the first where the trap was the packing rule rather than the build.

Docs drift. The bot named its own no-anchor mode outright — 2 changed file(s) yielded no anchor … this is not a clean bill of health — which is exactly why the hand sweep exists; it fired (@objectstack/cli → 20 files) with all target tokens at zero. ⚠️ I measured the base mismatch myself: the tool ran at fcddd151c3, the bot at efd6b43ace, and three content/ pages differ across that range (automation-api.mdx, package-api.mdx, control-flow.mdx). All three carry zero of this change's eight tokens, against controls firing on each page. Immaterial — but measured, not assumed, and this check has now come back non-empty twice today.

⭐ The out-of-scope item you declined to touch is the right call, and worth naming. bin/run.js:103 says the EPIPE "arrives synchronously inside the write", while this run's observer shows the completion delivered from the socket handle's close callback. You left it because it is a claim about arrival timing, not about which writer wrote, and because #16686's two probe legs were not re-measured here. That is the over-reach fence working: a sentence you have reason to doubt but have not measured is not yours to rewrite in passing.

What I accept on your measurement rather than re-running: the observer legs themselves. The controls are the right ones and they move in opposite directions (3/3 raw, 0/3 through console.error), and on the 0/3 legs the observer still recorded the EPIPE arriving and Console re-attaching its noop — so the zero is a reading, not a blind instrument. The ablation into an untracked sibling copy rather than a mutated tracked file, with restore proven by observing state (ablated copy present? no, git status --porcelain packages/cli: []) instead of by an exit code, is the correct shape.

Marking ready for review, then arming auto-merge, in that order.

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