Part 2 of the faceted plan, Phase 4 (steps 3-4). Size-only detection
was blind to metadata-sidecar edits; a size-stable book is changed by
EDITING its metadata.opf/metadata.json/cover — previously invisible
until a force rescan.
- Sidecar manifest fingerprints (media_scanner_manifest.go): the
manifest stats exactly the names the extractors consume (metadata.opf,
metadata.json, findSidecarCover patterns incl. <basename>.<ext>), so
manifest and extractors can never disagree. Shape v1:
{v, entries:[{n, s, m (unix nanos — second granularity would hide
edits landing in the backfill scan's own second), h (sha256 — covers
included: the repoint ladder needs a baseline hash for any stat-
drifted sidecar; a hashless cover turns harmless mtime drift into a
re-extraction, the exact flood this design kills)]}.
- Evaluation ladder in cost order: stat pairs identical → skip with
ZERO bytes read; stat drift → hash that sidecar (equal = host repoint
reconciliation, stat pair refreshed, no re-extraction; differing =
changed); NULL stored manifest → backfill only, NO re-extraction
(deploy-day rule: the first scan after release must not look like an
mtime flood).
- Change path: re-read full row, extractMetadata once and pass it
through updateMediaItemWithMetadata (preExtracted — metadata_overrides
stay protected), run syncPlaylistCollectionsAfterCreate (Correction 2:
a reading-order entry added to an EXISTING book now creates its
collection; add-if-missing is idempotent), store a fresh full
manifest. Creates seed their manifest at insert time.
- Multifile folder/zip books intentionally keep Phase 3 behavior: their
change path does not consume sidecar extractors, so gating them would
flip books 'changed' without picking anything up (plan correction —
the plan's §3 multifile note assumed otherwise).
- UpsertMediaScanState + GetMediaScanState queries.
Tests: media_scanner_manifest_test.go (ladder unit tests — fast path,
repoint, same-size drift, appear/vanish, unhashable legacy entries);
TestScanManifestLifecycle (seeding, unchanged-skip stability, repoint
reconciliation with stat-pair refresh assertion, same-size edit
consumed, playlist sync on the change path + idempotency, no-leak
guard). Container runner.
John O'Keefe
6750e9e0dc