All PATH operands belong to a single scan: every operand seeds the
shared walk worker pool, and each pass (walk, stat, hash, update)
runs exactly once over the whole scan, so pass totals, percentages,
and ETAs are scan-global. The per-operand walk/hash/update cycles and
their stderr operand announcements are gone; duplicate paths from
overlapping operands are deduplicated before stat.
The update pass now commits in batched transactions (10k changes per
batch) instead of one scan-wide transaction: the filesystem is
authoritative and the database is an eventually-consistent reflection
of it, so scan-level atomicity buys nothing, while batches keep the
WAL small and let concurrent reports observe progress.
scan now synchronizes a database that survives between runs
(SFDUPES_DATABASE, default /var/lib/sfdupes/db.sqlite) instead of
emitting a stream: operands are resolved to absolute paths, unchanged
files (same size, mtime not newer than recorded) are never re-read, new
and changed files are hashed, and records under the scanned operands
that were not verified this run are deleted; records outside the
operands are untouched. All changes commit in a single transaction, and
WAL journaling with a busy timeout keeps a report run during a cron
scan safe.
report and trees read the database (no positional arguments); the
NUL-terminated stream format, its parser, and the malformed-record
handling are gone. The driver is modernc.org/sqlite (pure Go), so
builds keep cgo disabled.
