# Flake ledger

Tests that have failed nondeterministically, with mechanism notes and hardening
status. Discipline: **any flake gets an entry, not a shrug** — a second
occurrence upgrades the entry from "observed" to "harden it." Rig flakes from
the two-host ladder (docs/TWO-HOST-RUNBOOK.md) land here too.

| # | test | occurrences | mechanism | status |
|---|------|-------------|-----------|--------|
| 1 | `spt-daemon brain_restart_survives_gaplessly` | 1× hosted Windows (2026-06-03, hung) | ConPTY stall under hosted-runner load | job `timeout-minutes` bounds it; not seen self-hosted |
| 2 | `spt-term digest_parses_a_real_pty_stream` | 3× gravity (2026-06-03; 2026-06-04 runs 26957386850, 26966738231) | sprint-collapse assert (`digest.rs`) — PTY input echo and the child's write are **concurrent writers** into the master-read stream; back-to-back `send_line`s let a later line's echo interleave mid-`Write(…)`, breaking the tool regex for that turn | HARDENED (2026-06-04): sends serialized — each line pumped back (adaptive echo-copy count, 2s/line bound) before the next, so no concurrent writer races an earlier line; failure asserts now print the raw transcript |
| 3 | `spt-daemon sync.rs torn_pull` + `concurrent_writes` | 1× (2026-06-03) | `wait_for_stream` deadline too tight under load | HARDENED: `wait_for_stream_except` 2s→10s; no recurrence |
| 4 | `spt-live context::write_context_suppresses_stale_llm` | 1× gravity (2026-06-04 run 26967808321) | test calls `write_context` (reads SPT_HOME node identity + epoch stamp) WITHOUT the `with_home` lock — a parallel `with_home` test's env swap + temp-dir teardown races the stamp's epoch write into a deleted home (`NotFound`) | HARDENED (2026-06-04): test wrapped in `with_home` — serializes on the home lock like every other SPT_HOME-touching test |
| 5 | `spt-daemon attach.rs:600` re-serve (`output gap: got seq 1 want 0`) | 1× kitsubito Linux (2026-06-15 run 27545857429, PR #14 stale-base CI) | re-serve replays the buffered output stream on re-attach; under load the new subscriber observed `seq 1` before `seq 0` — an ordering/timing gap in the re-serve sequence assert, not a content error. Subsystem disjoint from the triggering change (PR #14 = digest-proof CLI key-fill, cannot touch attach sequencing) | OBSERVED 1×: did NOT reproduce on the clean-base rerun (`gh pr update-branch` onto post-#15 main → green both runners). Not hardened; a 2nd occurrence upgrades to harden |
| 6 | `spt-term tests/stream.rs:49 bounded_backpressure_stalls_an_unconsumed_reader` | 1× hfenduleam Windows (2026-06-15 run 27545857429, PR #14 stale-base CI) | asserts an unconsumed bounded stream stalls the writer-side reader; got `16 -> 82` (reader advanced past the bound) — a timing-sensitive backpressure assert racing the bound check under hosted-runner load. Subsystem disjoint from PR #14 (digest-proof CLI) | OBSERVED 1×: did NOT reproduce on the clean-base rerun (green both runners). Not hardened; a 2nd occurrence upgrades to harden |
| 7 | `spt-daemon::attach attach_survives_target_brain_restart_exactly_once` | 1× kitsubito (2026-06-16 run 27595180782 attempt 1, M11-W3) | **TIMEOUT, not an assertion fail** — SLOW>60>120>180>TERMINATING, nextest TIMEOUT at the 240s cap (`attach.rs:600`). A heavy multi-process brain-restart-exactly-once test on the slow shared kitsubito box under concurrent load (n1-gate on the same runner + a parallel `ci.yml` docs-publish run firing simultaneously). W3-INDEPENDENT: Windows green end-to-end; ALL tunnel tests passed fast on Linux too (tunnel_e2e 0.941s, loopback_tunnel_backpressures_without_loss 1.091s) — a logic bug fails both runners deterministically, this timed out on one under load | observed; cleared by `gh run rerun --failed` (builds reused, no re-tag). Harden if it recurs — candidate: raise this test's per-test nextest timeout, or serialize it off the concurrent n1-gate slot |
| 8 | CI build step `Build notify-shell` (kitsubito Linux) | 1× kitsubito (2026-06-16 run 27652755792 attempt 1, v0.8.1 PR #17) | crates.io dep-download blip during the notify-shell build — `download of config.json failed, curl failed` fetching `serde_json`: a transient registry/network fetch failure on the runner, not a code or test fault (a real dep break fails both runners deterministically; this hit one runner once) | observed; cleared by `gh run rerun --failed` (attempt 2 green, builds reused). Harden if it recurs — candidate: a cargo fetch retry / registry cache warm on the runner |