orchestrator/status-line.ts — dynamic worker region

The live status display for interactive runs. Not a TUI: a region redrawn in place with cursor-up + clear-line escapes — no alternate screen, no cursor addressing beyond that.

OutputWriter

createOutputWriter(stream, opts) is the serialization point for all logger stdout. Inert (pure passthrough) on non-TTY streams and when disabled (CI). When active:

• setRegion(lines) / setStatus(line) replace the display; unforced redraws are throttled (minRedrawMs, default 100 ms), task start/finish events force.
• Forced redraws coalesce behind forceFloorMs (default 30 ms, 0 disables): a forced set within the floor marks the content dirty and schedules ONE trailing draw (unref’d; canceled by any draw and by clearStatus) for floor expiry, so the final state always lands. First draw after idle is immediate. Measured: 6,540 forced redraws ≈ 6.7 MB of ANSI on a 3,270-task warm run → ~20 KB.
• write(chunk) — any ordinary content — erases the region first (single line: ESC[2K\r; taller: \r ESC[nA ESC[J), writes the content, then redraws. The region can never interleave with task output. The erase always uses the height of the previous draw; the new draw establishes the new height, so the region may grow and shrink freely (pins arriving).
• A chunk ending mid-line (focused streaming) holds redraws until a newline restores column 0.
• clearStatus() is permanent (run end).

Off a TTY, coalesce: true holds writes and hands them to the stream once per turn of the event loop (setImmediate), in order; settle() hands over what is held and writes straight through from then on. A warm 476-package run wrote each of its 952 task lines as its own syscall; coalesced, the warm run’s wall went 184.0 → 167.8 ms (min of 15, interleaved compiled binaries, item 753). Only run()’s own terminal logger asks for it (a caller reading a stream right after a write still sees it), and it settles in runEnd, before the summary prints below the held lines, and again in run()’s finally for a throw that never reached runEnd: nothing is held when the verb returns and bin.ts lets the loop drain. A TTY is never coalesced; its region redraws already serialise the writes.

formatStatusRegion

A blank separator line, a pinned zone, one row per worker slot, then the live summary section.

The pinned zone (owner: “always pinned until exit”):

• Persistent — a ▸ row (no elapsed, running, the id) for every ready persistent task (its outcome lands at ready while the child keeps running; the orchestrator SIGTERMs persistent children when the graph finishes, so runEnd is the honest end). Pins keep identity-colored ids — status colors only on glyph + outcome.

A failure is not pinned: it is logged the moment it happens as a permanent row in the stream (formatFailureLine: red ◼, the exec time, failed, miss / no-cache, the id — the exit code and the output live in the frame, which replays at runEnd above the summary, failedLabel in its header and footer). The region held a Failures zone once; the permanent row replaced it, and this page kept describing the zone until 2026-09-16.

Slot rules (the point of the design — the display derives from the stable worker set, not the churning task set):

• Sized min(concurrency, 10) at runStart; the footer’s info row states the pool (C workers).
• A task takes the lowest free row and stays there for its whole life; idle rows hold their place dimmed, so the height and the rows never shift.
• More running tasks than rows queue for a freed row and surface as a … +k more running line under the rows.
• A worker row leads with the ticking elapsed time (no glyph), then running and the id. Ids are identity-colored (paintIdParts): project hue hashed stably from the project name, task in fixed pink — never status colors. The id is the last column and is never truncated.

Below the rows, the live summary section: the same section (formatSummarySection) the final footer prints, filling in as the run proceeds, so the live numbers and the final summary can never disagree.

Lifecycle

defaultLogger drives it through the optional runStart / taskStart / taskComplete / runEnd hooks. A 100 ms unref’d ticker advances the elapsed times between events (there is no spinner). Focused flow: the region lives only while dependency nodes run and is killed permanently when a requested node starts streaming.