---
created_at: 2026-11-06T18:56:28.621577+00:00
generated_by:
  harness: codex
  provider: OpenAI
git_ref: 495c0915
scope: code
substantive: true
raw_file: 20261106T185628Z_495c0915_215e9b_prompt_io.raw.md
---

## Prompt

User reported a different-feed overlap failure and asked whether
a fix could be extracted without importing broader history work.
PDB confirmed MNQ March 2027 one-second history timed out and
returned None, producing NoData. After continuing PDB, sibling
history and quote tasks terminated while pikerd remained alive.
User requested continuing with the narrow backport.

## Response summary

Partial backport of the NoData/DataUnavailable catch from
0846cbd4a4197e47415689cf5e9d146ba3174c32 into
maybe_fill_null_segments(). The existing gap fallback remains in use.
A new parametrized regression uses real null detection and verifies
that a sibling in the same nursery survives the failed repair.

Both new cases failed before the catch. The focused history suites
passed after it: 17 passed. This does not qualify live overlap or fix
IB reset churn or the separate Tractor completion-callback assertion.

## Files changed

- `piker/tsp/_history.py`: existing downstream exception catch.
- `tests/test_history_backfill.py`: sibling survival regression.

## Human edits

User supplied live reproduction, PDB locals and cancellation logs,
and explicitly constrained scope to a small history extraction.
The production catch is copied from existing downstream commit
0846cbd4, not newly designed here. New regression is agent-authored;
no direct human source edits observed during this patch. Review and
live qualification remain with the user.