fix: release 3.7.0 polish — WAL reopen, search errors, hash stamp

[igorls]

Summary

Polish before Milla reviews #2129 (develop → main for 3.7.0).

From bot review on #2129

1. sqlite_exact: retire immutable RO cache only when both -wal and -shm exist (Copilot). Partial pairs no longer force a reconnect that raises.
2. palace.get_collection: retry without options when third-party backends raise TypeError on the kwarg (Copilot).
3. convo_miner content_hash: stamp only on chunk_index == 0 so multi-conversation bundle hashes are not O(N²)-duplicated (Copilot + Codex P2).

Windows CI flake

test_hybrid_search_enrichment_isolates_chunks... hit KeyError: 'results' when search returned an error envelope without the key. Search error paths now always include results: [], and the test asserts the full envelope.

Deferred (not blocking 3.7.0)

• Codex P1: re-mine alias ownership when every conversation matches another source — real design work; follow-up issue preferred over last-minute rewrite.

Local validation

uv run ruff check .          # clean on touched files
uv run pytest tests/ --ignore=tests/benchmarks
# 3498 passed, 31 skipped

Test plan

• Full local suite
• New partial-WAL sidecar regression
• Search error envelope includes results: []

[Copilot]

Pull request overview

Polish changes for the 3.7.0 release branch to make read-only SQLiteExact behavior more robust around WAL sidecars, harden search result “error envelope” shape for callers, and reduce unnecessary content_hash duplication during conversation mining.

Changes:

• Adjust SQLiteExactBackend immutable reader reopening to retire the cache only when both -wal and -shm sidecars exist, and add a regression test for partial sidecar state.
• Standardize search error returns to always include results: [], and strengthen tests to assert the full envelope to avoid CI flakes.
• Stamp content_hash only on chunk_index == 0 to avoid O(N²) duplication for bundled conversations.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
mempalace/backends/sqlite_exact.py	Reopen immutable RO cache only when WAL sidecar pair is complete.
tests/test_sqlite_exact_backend.py	Adds regression coverage for partial WAL sidecar state and reopens-on-writer behavior.
mempalace/searcher.py	Introduces _search_error_result() and routes error paths through it to guarantee results: [].
tests/test_searcher.py	Asserts search error envelopes include results: [].
tests/test_closets.py	Improves hybrid-search assertions to surface full search envelopes on failure.
mempalace/palace.py	Adds a retry path for plugin backends that reject the options kwarg.
mempalace/convo_miner.py	Limits content_hash stamping to chunk 0 to avoid per-chunk duplication.

Suppressed comments (1)

mempalace/palace.py:267

• Same issue in the legacy-call fallback: checking only for the substring "options" in the nested TypeError is too broad and can cause an unintended retry without options. Restrict this to the specific unexpected-kwarg message for options.

                collection = backend_obj.get_collection(palace_path, **legacy_kwargs)
            except TypeError as nested:
                if backend_options is None or "options" not in str(nested):
                    raise

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Reject incomplete WAL sets instead of freezing recall

When an incomplete sidecar set is persistent rather than a transient writer startup—for example, a restored palace containing the database and a valid -wal but no -shm—this condition keeps returning the immutable base-database snapshot for as long as the cached reader is used. Committed rows may exist only in the WAL, and _connect_read_only explicitly rejects this same state because it cannot read it safely, so silently reusing the handle can omit memories instead of surfacing the actionable BackendError.

AGENTS.md reference: AGENTS.md:L9-L9

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[chatgpt-codex-connector]

Restrict fallback to unexpected options keyword errors

When read_only=True and a backend accepts options but raises an internal TypeError whose message happens to mention that word, such as TypeError("invalid options value"), this branch misclassifies the real backend failure as signature incompatibility, invokes initialization again, and silently drops the read-only option. This can hide the original error, duplicate side effects, and return a writable collection despite the caller's request; the fallback should match the specific unexpected-keyword signature error rather than any message containing options.

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