Ubuntu CI (and other distro builds) ship a sqlite3 shell compiled without
the sqlite_dbpage virtual table that .recover requires, so PATH presence
alone let the lane attempt and fail with 'no such table: sqlite_dbpage'.
find_sqlite3_cli() now probes .recover on a scratch DB once; the test skip
gate uses the same probe, and the no-CLI guidance names the capability
requirement.
Fixes#80205: when one ordered rowid-edge probe failed,
_salvage_rowid_bounds() substituted the whole SQLite rowid domain and
_copy_table_salvage() burned the 10,000-query budget bisecting a
synthetic tail that could not contain rows, silently omitting readable
boundary rows (field case: message 76882 of 76882). Two-part fix:
* _probe_populated_edge(): gallop outward from the surviving edge with
doubling offsets; a clean 'no rows beyond X' probe caps the domain in
O(log range) queries instead of exhausting the budget on it.
* exact-key singleton salvage: a one-row range scan must advance the
cursor past the hit into the damaged sibling page to prove exhaustion,
which discards the already-produced row; 'WHERE rowid = ?' stops at
the hit, recovering the boundary row exactly like sqlite3 .recover.
* the strict-path refusal now points users at --allow-partial.
New last-resort lane for --allow-partial when the sessions/messages
table schemas themselves are unreadable (previously a hard refusal even
though page-level salvage recovers the rows fine). If a sqlite3 CLI is
on PATH, shell out to '.recover --ignore-freelist' into a scratch
lost_and_found DB, then heuristically map rows back into a fresh
SessionDB-schema database (hermes_cli/session_lost_and_found.py):
classification keyed on nfield counts + sentinel columns (session ids
matching ^\d{8}_\d{6}_, roles in user/assistant/tool/system, known
source strings), covering the current 54-col sessions layout, the
52-col historical layout, a 14-col legacy identity-only salvage,
rowid-alias messages rows and 18-col session_model_usage rows. Missing
parent sessions are stubbed (children are never deleted for FK
cleanup), FTS is rebuilt at the end, and output is labeled BEST-EFFORT
everywhere. Without the CLI the error names the sqlite3 requirement
with actionable guidance. Mirrors a successful manual recovery of a
real corrupt state.db (2026-08-12), and this lane was validated against
that preserved file: 32 sessions / 7 messages / 4 usage rows mapped,
integrity_check ok, opens via SessionDB.
Also fixes#72291: the source-fingerprint 'bundle changed while it was
being copied' error now enumerates that the parent interactive CLI
session itself counts as a Hermes process and suggests a fresh shell or
an immutable snapshot.
Tests use real physical page corruption (flipped b-tree/schema header
bytes), skip the CLI-dependent path cleanly when sqlite3 is absent, and
keep the mapper unit tests binary-independent via a synthetic
lost_and_found DB. Sabotage-verified: reverting the fixes makes the
regression tests fail with the exact field failure shape.
Teknium