Thanks for the narrowly scoped, read-only importer and privacy tests. The full suite passes here with the zstandard extra (1507 passed, 9 skipped), but checking the external format contract uncovered a current-version/stale-generation blocker at 84d64abf2c3d.

Current upstream DSH (deepseek-ai/deepseek-harness at d347e703908d0406b7a7ef80e3a0e594d86b2215) declares SESSION_FORMAT_VERSION = 2. Its JSONL backend writes session.v2.jsonl[.zstd], retains immutable v0/v1 predecessors during migration, and selects the numerically highest canonical generation:

• Current version constant
• Canonical generation layout and migration/read selection

The importer only discovers session.jsonl / session.jsonl.zstd and accepts header version 0. Therefore fresh current-format sessions are silently missed. More importantly, if migration retained a v0 file next to the authoritative v2 file, this implementation successfully harvests the obsolete v0 snapshot rather than refusing the unsupported current session.

I reproduced the latter offline with the PR's valid v0 fixture plus a neighboring session.v2.jsonl: harvest_dsh() returns the old user/assistant conversation. With an explicitly version-gated reader, the safe result is to refuse that session with a useful diagnostic until its highest generation is supported, not fall back to retained history.

Please select the highest canonical generation first and fail closed on unsupported generations. Then either support the currently released logical format through a validated codec/export boundary, or explicitly pin/document this as a legacy-v0-only source with a producer version and representative fixture. Please cover fresh v2-only sessions and coexisting v0/v1/v2 generations in tests. This is a concrete format-boundary issue; no DSH execution backend or paid-model experiment is needed.

Thanks for review. I addressed this by supporting the current v2 logical format rather than documenting DSH as a legacy-v0-only source.

The importer now discovers canonical session.jsonl / session.vN.jsonl files, including their .zstd variants, groups retained generations by session directory, and selects the numerically highest generation before parsing. It supports v0, v1, and v2. If the selected highest generation is unsupported, it skips that session without falling back to a retained predecessor; --progress and debug logging report the selected file, highest generation, supported versions, and upgrade guidance.

For v2, the reader now validates the published header boundary, including the required isSeeded field and allowed header keys, validates consistency between isSeeded and session/end-seed lineage markers, and replays the ordered surface before deriving visible user and assistant text. It also expands the JSONL storage codec's compressed sourceEventSeqs ranges (for example, [start, end]) before validating and applying replacements. This prevents text from a shadowed pre-compaction assistant message from being exported.

I added coverage for:

• fresh v2-only sessions;
• coexisting retained v0/v1/v2 generations, asserting that v2 is selected;
• an unsupported highest generation, asserting that no older generation is harvested and that a diagnostic is available;
• v2 replacement provenance encoded as compact sequence ranges;
• v2 header and seeded-lineage validation; and
• a sanitized Zstandard v2 fixture generated from a DeepSeek Harness master build at d347e703908d0406b7a7ef80e3a0e594d86b2215.

The reader remains a pure, read-only Python importer: it does not start DSH, require a DSH execution backend, or make provider calls.

Validation run:

python -m ruff check skillopt_sleep/harvest_dsh.py tests/test_harvest_dsh.py
python -m pytest -q tests/test_harvest_dsh.py

70 passed