René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"gap CLI: a run under load can end non-zero (an internal error) where it should complete","articleBody":"## Summary\n\nUnder load, the gap CLI sometimes ends a run with a non-zero exit where the run should complete. Twice it was an internal error (\"This is a bug in oracle-gaps\"). The e2e oracle's fixed-seed shard 3 failed in 2 of 8 Linux runs on #55's head. Each failure had a different symptom, and neither one reproduces when the unit runs alone.\n\n## Traces\n\n1. **CI, job [132489470739](https://github.com/TanStack/oracles/actions/runs/43608937018/job/132489470739)** (run 43608937018), commit 16f510c, \"Gap report end-to-end oracle (fixed seed, 3/3)\":\n   - Unit: `fixed seed 20261105: generated`, history `ORACLE_PATH=1` (fault `brokenOwner`).\n   - Error: `a history entered \"refused brokenOwner\", which the property does not declare`.\n   - Meaning: the CLI exited non-zero on a `brokenOwner` history. The history owes exit 0 with blocked mutants (`blocked by brokenOwner`). The log does not show which non-zero exit or its error.log.\n   - Replay: `ORACLE_SEED=20261105 ORACLE_PATH=1 ORACLE_PROPERTY='oracle-gaps.report' ORACLE_UNIT='random seed: generated' vitest run -t '^oracle-gaps\\.report(?: | > )random seed: generated$'`\n2. **Classic Arca VM, tag r55-gen-shard3**, commit edb24ba (16f510c plus a test-only diagnostic), the same shard-3 command:\n   - Unit: `fixed seed 20261105: an edit sequence through the daemon`, step `dieMidCheck`.\n   - Error: `through the daemon at dieMidCheck: the run wrote a line on stderr that is not a line of the stream: This is a bug in oracle-gaps, not in your oracle. Its stack is in \u003cpackage>/out-daemon/error.log.`\n   - The VM was shared with another session's long loops when this ran.\n\nThe shard command, from `packages/oracles`:\n\n```sh\npnpm exec vitest --run --maxWorkers=2 --config oracle-gaps/vitest.config.mjs gap-report-oracle -t \"$(node scripts/pr-shards.mjs pattern oracle-gaps-fixed-seed 3)\"\n```\n\n## Tally\n\n| Commit | Where | Shard-3 runs | Failed |\n| --- | --- | --- | --- |\n| 16f510c (#55 head) | CI, Classic Arca, Arclets | 8 | 2 |\n| 35422e3 (`main`) | Classic Arca, Arclets | 6 | 0 |\n| ed091f3 (#55 before the #58 merge) | Arclets | 4 | 0 |\n\nThe unit `generated` alone passed on 16f510c locally (macOS) and on the VM, and on `main` locally. All 12 runs on the dedicated Arclets passed, with no internal error.\n\n## Next\n\n- Reproduce under load on purpose: shard 3 with a CPU hog on the Arclets, 4 runs on #55's head (with the diagnostics, which print each exit-3 run's error.log) and 4 on `main`. The result decides whether this is #55's or older.\n- #55 (b959d4c) now makes the incremental violation print a cold run's error log when that run exits 3, so the next failure in CI shows its stack.\n- Related: the deterministic-cut follow-up (cut runs by work count, not wall time; \"determinism under load\"), which targets timing-dependent outcomes.\n\nThis issue was written by Isaac.\n","author":{"url":"https://github.com/KyleAMathews","@type":"Person","name":"KyleAMathews"},"datePublished":"2026-11-14T21:35:13Z","url":"https://github.com/TanStack/oracles/issues/83"}