The per-chunk timeout fired correctly but reported almost nothing, so every
diagnosis cost a CI round-trip. run-tests.cjs logged chunk START only — no
timestamp, no duration, no end line — then on a kill printed all ~55 basenames
and asked the operator to work out whether output kept flowing (slow) or
stopped early (hang). It could not name the in-flight file because the child is
spawned with stdio inherit, deliberately, per #3597/#1051.
Three additions.
Per-chunk elapsed timing on every path, not just failures, so drift toward the
cap is visible before it becomes a kill. Every timing number in the
investigation behind this had to be reconstructed by hand from GitHub log
timestamps.
A second, machine-readable reporter running ALONGSIDE the human one, writing
NDJSON to its own file. On a kill that file is read back and the files with a
test:start and no matching completion are named, with the staleness of the last
event, so "stopped 480s ago at X" reads differently from "still emitting at
kill". stdio stays inherit and nothing is piped or tee'd — the maxBuffer and
live-output risks that shaped the original design are untouched.
Ranking of the killed chunk's files by known weight, flagging any absent from
tests/test-timings.json, since an unweighted file is an unknown quantity.
Two details that are correct rather than lucky. Passing --test-reporter at all
replaces node's implicit default, so the human reporter is now named explicitly
and reproduces node's own selection (spec on a TTY, tap otherwise) — visible
output is unchanged. And the destination path's chunk index is zero-padded to a
fixed width because FIXED_OVERHEAD is computed ONCE before chunking; a
variable-length path would have silently mis-accounted the Windows 32,767-char
argv ceiling and reintroduced #3597. The reporter flags are added to
FIXED_OVERHEAD exactly as --test-force-exit is.
The multi-reporter pairing and the stream.compose reporter contract were
confirmed against Node's v24 documentation, not recalled — the first draft
carried them as an unverified assumption and said so.
Also corrects a stale comment claiming the 600s cap sits "below the 20m job
cap". The lane is sharded 3x at timeout-minutes: 45; the windows shards were at
19m when chunk 1/5 was killed on b351c83e0 and c3e667df3. The per-chunk cap is
now the binding constraint, and the old silent-cancel model leads to the wrong
conclusion.
Verification runs on the remote runner.
Closes#4012
8497833a15