# P3-S25.1D-R — INTERRUPTION / RESUME RECOVERY ```text Document type : RECOVERY REPORT (governance-adjacent, verification-only) Phase : P3-S25.1D-R — Recovery of the failing interruption/resume verification of P3-S25.1D Date : 2026-08-28 Scope : ONLY the isolated interruption/resume test. No real-source ingestion, no CHUNK 11, no ML, no production changes. Authoritative evidence : ml/p3/p3_s251_external_ingest/multichunk_benchmark/ recovery/output/*.json ``` ## 1. Session origin and objective This session recovers the unresolved interruption/resume verification of P3-S25.1D. The previous session ended (~2 h 39 m) after it reached its action limit while investigating the interruption/resume failure; an unresolved verifier result was recorded and a likely verification-driver defect was identified. This session isolates that defect, independently verifies the corrected path, and does NOTHING else. ## 2. Pre-session state audit - Latest handover read: no `SESSION_HANDOVER_*P3_S25_1D*` file exists in the repo (the expected `P3_S25_1D_MULTI_CHUNK_TURN_BENCHMARK.md` / `P3_S25_1D_EXECUTION_STRATEGY.md` were never created). The authoritative phase reports used were `docs/P3_S25_1D_VERIFICATION_DRIVER_HARDENING.md` and `docs/P3_S25_1D_MULTI_CHUNK_INVARIANCE.md`, plus the machine-readable manifest below. - Machine-readable authority for the failure: `multichunk_benchmark/output/multichunk_benchmark_manifest.json` -> `status.interruption = false`, `all_pass = false`. This is the authoritative record of the ORIGINAL failure. - Working tree at session start: `git rev-parse HEAD` = `a52b38eeb4ab74a500f778a028ee8ac7336920c1` == `git ls-remote origin HEAD`; branch `main`; remote = `SniperGold_ML.git`; stash EMPTY. - **Preflight deviation (documented)**: `git status --short` reported untracked P3-S25.1D artifacts left by the interrupted previous session: `docs/P3_S25_1D_MULTI_CHUNK_INVARIANCE.md`, `docs/P3_S25_1D_VERIFICATION_DRIVER_HARDENING.md` and the whole `ml/.../multichunk_benchmark/` directory. No tracked file was modified (`git diff --stat` empty). These exact artifacts are the subject of this recovery and are committed unchanged at close-out; nothing was reset, cleaned, stashed, merged, cherry-picked or re-written. ## 3. Real checkpoint immutability (before any test) ```text path : ml/p3/p3_s251_external_ingest/output/s251_real_checkpoint.json checkpoint_sha_before: 47da8f020426bec67e9f7865519e900a28c286ba1d13a15bee6a8c0f5307afc7 last_completed_chunk : 10 next_chunk_id : 11 (derived: last_completed_chunk + 1) next_byte_offset : 163,578,081 (checkpoint next_byte_start / byte_offset) ``` The checkpoint was NOT modified at any point during this session. ## 4. Original failure (recorded) - `output/multichunk_benchmark_manifest.json` (run ended 2026-08-28 07:31:10Z): - verifier_hardening_8_of_8 : true - mutation_12_of_12 : true - semantic_invariance : true - **interruption : false** <- the failing test - batches_pass 1/2/4/6 : true - all_pass : false - After the manifest was written, the previous session re-ran the interruption test alone at 07:39 and its PASS result overwrote `output/multichunk_interruption.json`; the ORIGINAL failing JSON (reported mismatch `continuous_run_hash = a4293…` vs `resume_output_hash = 7d7…`) is NOT preserved anywhere on disk. The manifest remains the authoritative record that the interruption test FAILED. The original 7d7… value cannot be recovered from any preserved file. ## 5. Isolation (machine-readable) `recovery/output/interruption_failure_isolation.json` records: ```text test_name : MULTI_CHUNK_INTERRUPTION_RESUME failure_type : RESUME_BOUNDARY_MISMATCH continuous_boundary_algorithm: line-safe actual consumed byte_end chaining (pos += len(raw)), identical to production resume_boundary_algorithm : OBSOLETE nominal split_atomic 24 MiB multiples (the original defective resume under isolation) continuous_hash : a4293a8adeef6cbc5ec464c574b1bc3930568e47a76f1f68234d4fd2787893b7 resume_hash : a4293a8adeef6cbc5ec464c574b1bc3930568e47a76f1f68234d4fd2787893b7 boundary_sequences_identical : false ``` ### Boundary comparison (continuous vs nominal-boundary resume) | chunk | continuous byte_start | resumed byte_start | continuous byte_end | resumed byte_end | |------:|----------------------:|-------------------:|--------------------:|-----------------:| | 0 | 0 | 0 | 25,165,841 | 25,165,841 | | 1 | 25,165,841 | **25,165,824** | 50,331,671 | 50,331,671 | | 2 | 50,331,671 | **50,331,648** | 75,497,504 | 75,497,504 | | 3 | 75,497,504 | **75,497,472** | 100,663,365 | 100,663,320 | | 4 | 100,663,365 | **100,663,296** | 125,829,196 | 125,829,152 | | 5 | 125,829,196 | **125,829,120** | 150,994,944 | 150,994,944 | Earliest divergence: chunk 1 — continuous starts at 25,165,841 (the actual line-safe end of chunk 0) whereas the nominal resume starts at 25,165,824, re-entering the 17-byte straddle tail of the tick record that chunk 0 had already consumed. Per the briefing rule (section 6) differing boundary sequences are sufficient evidence of a verifier/driver defect — recorded. ### Why the original run produced a hash mismatch Under line-safe reads the re-read 17-byte fragment parses as a malformed partial line (`column_count`), so the VALID-row hash is unchanged (`resume_hash == continuous_hash` in this reconstruction). The original failing run's semantic mismatch (7d7…) is consistent with the defect class already recorded in `P3_S25_1D_VERIFICATION_DRIVER_HARDENING.md`: chunking at nominal fixed byte multiples drops each straddling record (the documented `N_BATCH = N_REF - 5`), and with any carry/offset misalignment. Mutation 7 of this recovery demonstrates the same semantic class: a 1-byte resume offset loses one real record (row count 1,689,968 -> 1,689,967, output-hash mismatch). The canonical invariant is byte-contiguity: the next chunk MUST start at the actual consumed end of the previous one. ### Smallest reproduction 2 atomic chunks, interruption after chunk 0, nominal-boundary resume: continuous chunk 1 [25,165,841..50,331,671) vs resumed chunk 1 [25,165,824..50,331,671) -> boundary divergence at the FIRST resumed chunk (full details in the isolation JSON, `smallest_reproduction`). ## 6. Root cause classification **A — VERIFIER DEFECT ISOLATED AND FIX VERIFIED** (see §10). - Root cause is in the DISPOSABLE verification driver (resume boundary reconstruction), NOT in the production parser (`s251_parse.py`), NOT in the production aggregator (`s251_aggregate.py`), NOT in the real checkpoint. No production-equivalent logic defect was found (the byte stream itself is processed identically by both paths once boundaries are correct). ## 7. Smallest reproducible failure progression Per the briefing, the failing case was reduced to the smallest reproduction before any fix verification: ```text 2 atomic chunks -> boundary divergence reproduced at chunk 1 (STOP, minimal) ``` No larger reproduction needed; the defect is a pure boundary-alignment defect present at the first resumed chunk. ## 8. Correction (verifier only) The corrected resume chains every resumed chunk on the ACTUAL line-safe consumed `byte_end` of the previous chunk and seeds the first resumed chunk with the DEEP-COPIED output carry of the last completed (trusted) prefix chunk — exactly the canonical batch-driver algorithm (`multichunk_benchmark.run_batch`). Implemented fresh in `recovery/test_interruption_resume_recovery.py`. No production file was touched. ## 9. Corrected isolated-test result (machine-readable) `recovery/output/interruption_recovery_result.json`: ```text corrected_run1 : all_match true (stops 1 and 3) corrected_run2 : all_match true (stops 1 and 3, fully recomputed) reproducibility: semantic_outputs_equal_run1_run2 = true ``` For every interrupted stop verified: ```text trusted prefix : chunks [0, stop) (in-flight chunk untrusted) prefix boundaries == continuous : true resumed boundary sequence == continuous : true per-chunk equality (id, byte_start, byte_end, byte_len, rows, m15/m30 counts+hashes, input/output state hashes, final state hash) : true for every chunk >= stop carry chain (input/output state hashes) : ok aggregate equality (rows, m15, m30, output hash, first/last ts, final state, output carry) : true ``` Key hashes (all runs, all stops): ```text rows_processed : 3,379,465 m15_count : 17,374 m30_count : 9,315 output_hash : a4293a8adeef6cbc5ec464c574b1bc3930568e47a76f1f68234d4fd2787893b7 m15_hash : 9c3c4b85d3c0a4209602f5797083b1d0fa573ab355c17c13ed3327b01ebe1abc m30_hash : 320caf981f6d597fc5bcaa393fe8753b7a5c19e1f6a0c7d5decbb80a50c22fbb final_state_hash: cb1e7d17d69cfec4e9697f575fc7458e6473da7172b4528e2a62846fb1e30ade first_ts : 1,052,092,863 last_ts : 1,076,518,492 ``` These equal the recorded P3-S25.1D continuous reference hash exactly. ## 10. Decision-gate classification Per the briefing decision rule: - `A — VERIFIER DEFECT ISOLATED AND FIX VERIFIED`: confirmed (boundary divergence reproduced; corrected test passes deterministically twice; 8/8 interruption mutations detected). - `B — INTERRUPTION SEMANTICS VERIFIED`: confirmed for the isolated case (exact output/state equivalence, see §9). - `C — PIPELINE / CHECKPOINT DEFECT`: NOT found. - `D — UNRESOLVED`: no (the exact boundary defect was conclusively isolated; the original 7d7… byte value is unrecoverable because the previous session overwrote its own failing JSON before stopping — this is recorded, not papered over). This does NOT certify multi-chunk execution at large, and does NOT set `SAFE_CHUNKS_PER_TURN`. ## 11. Mutation detection (interruption-specific, 8/8) `recovery/output/interruption_mutations.json` — 3-atomic-chunk disposable range, stop after chunk 0: | # | Mutation | Detected | Evidence | |---|-------------------------------|:--------:|----------| | 1 | wrong resume byte offset | yes | boundary-mismatch + chunk-sig chunk 1 | | 2 | skipped chunk | yes | coverage, row-count, output-hash mismatch | | 3 | duplicated chunk | yes | coverage [1,1], chunk-sig chunk 2 | | 4 | wrong boundary sequence | yes | boundary-mismatch chunk 2 | | 5 | wrong input carry | yes | chunk-sig + output-hash mismatch | | 6 | post-chunk carry used as input| yes | chunk-sig + rowset-count + output-hash | | 7 | mutated checkpoint state | yes | boundary + row-count (1 record lost) + hash | | 8 | dropped prefix output | yes | chunk-count + row-count + hash mismatch | Result: **8/8 DETECTED** (fail-closed; no mutation escaped). ## 12. Real checkpoint after recovery ```text checkpoint_sha_after : 47da8f020426bec67e9f7865519e900a28c286ba1d13a15bee6a8c0f5307afc7 == checkpoint_sha_before : TRUE last_completed_chunk : 10 next_chunk_id : 11 next_byte_offset : 163,578,081 ``` ## 13. CHUNK 11 / new source processing ```text CHUNK 11 = NOT PROCESSED ``` No new real-source byte beyond 163,578,081 was read. All testing used only the already-committed disposable bench range [0, 150,994,944) (6 × 24 MiB atomic chunks within chunks 0–10). No Dukascopy, no ML, no production MQL5, no F1–F4 / Candidate Setup / FEATURE_CONTRACT/label changes. ## 14. P3-S25.1D overall status **UNRESOLVED (unchanged by this recovery).** The isolated interruption/resume path is now verified, but the broader P3-S25.1D multi-chunk turn benchmark, the full interruption matrix and its manifest are NOT re-run here and remain open. `SAFE_CHUNKS_PER_TURN` is NOT set. `docs/CURRENT_PROJECT_STATE.md` is NOT changed by this recovery. ## 15. Required artifacts (this recovery) ```text recovery/interruption_failure_isolation.py recovery/test_interruption_resume_recovery.py recovery/test_interruption_mutations.py recovery/run_interruption_recovery.py recovery/output/interruption_failure_isolation.json recovery/output/interruption_recovery_result.json recovery/output/interruption_mutations.json recovery/output/interruption_recovery_manifest.json docs/P3_S25_1D_R_INTERRUPTION_RECOVERY.md (this report) docs/SESSION_HANDOVER_2026-08-28_P3_S25_1D_R_INTERRUPTION_RECOVERY.md ``` The original failed P3-S25.1D evidence (manifest `interruption: false`) is preserved untouched; nothing historical was overwritten by this session. *End of P3-S25.1D-R interruption recovery report.*